BRITIS! m Bulletin of the British Museum (Natural Histo P^r 9 British Museum (Natural History) London 1985 Dates of publication of the parts Nol No 2 No 3 No 4 No 5 No 6 No 7 . 28 June 1984 . 26 July 1984 .30 August 1984 . 27 September 1984 25 October 1984 . 29 November 1984 20 December 1984 ISSN 0007-1498 Printed in Great Britain by Henry Ling Ltd, at the Dorset Press, Dorchester, Dorset Contents Zoology Volume 47 No 1 Miscellanea Page A revision of the genera Trachelostyla and Gonostomum (Ciliophora, Hypotrichida), including the redescriptions of T. pediculiformis (Cohn, 1866) and T. caudataKahl 1932. ByM. Maeda&P. Carey 1 Notes on Atlantic and other Asteroidea. 4. Families Poraniidae and Aster- opseidae. By Ailsa M. Clark 19 The larval and post-larval development of the Thumb-nail Crab, Thia scutellata (Fabricius), (Decapoda: Brachyura). By R. W. Ingle . . 53 Description of a new species of Sylvisorex (Insectivora: Soricidae) from Tanzania. By P. D. Jenkins 65 A new species of the Hipposideros bicolor group (Chiroptera: Hipposideridae) from Thailand. By J. E. Hill & S. Yenbutra 77 No 2 A review of the Mastacembeloidei, a suborder of synbranchiform teleost fishes Part II: Phylogenetic analysis. By Robert A. Travers .... 83 No 3 A review of the anatomy, taxonomy, phylogeny and biogeography of the African neoboline cyprinid fishes. By Gordon J. Howes . . . .151 No 4 The haplochromine species (Teleostei, Cichlidae) of the Cunene and certain other Angolan rivers. By Peter Humphry Greenwood . . . .187 No 5 Miscellanea Notes on testate amoebae (Protozoa: Rhizopoda) from Lake Vlasina, Yugoslavia. By Colin G. Ogden 241 Description of a neotype for the holothurian Oncus brunneus (Forbes MS in Thompson 1840) from Strangford Lough, Northern Ireland (Holothurioidea: Dendrochirotida). By J. Douglas McKenzie . . . 265 Three new species of Varicorhinus (Pisces, Cyprinidae) from Africa. By K. E. Banister .273 Phyletics and biogeography of the aspinine cyprinid fishes. By Gordon Howes 283 New bats (Mammalia: Chiroptera) and new records of bats from Borneo and Malaya. By J.E. Hill &C. M.Francis ... .305 No 6 Anatomy and evolution of the feeding apparatus in the avian orders Coracii- formes and Piciformes. By P. J. K. Burton 331 No 7 A revision of the spider genus Cyrba (Araneae: Salticidae) with the description of a new presumptive pheromone dispersing organ. By F. R. Wanless . 445 Bulletin of the British Museum (Natural History) Miscellanea Zoology series Vol 47 No 1 28 June 1984 The Bulletin of the British Museum (Natural History), instituted in 1949, is issued in four scientific series, Botany, Entomology, Geology (incorporating Mineralogy) and Zoology, and an Historical series. Papers in the Bulletin are primarily the results of research carried out on the unique and ever-growing collections of the Museum, both by the scientific staff of the Museum and by specialists from elsewhere who make use of the Museum's resources. Many of the papers are works of reference that will remain indispensable for years to come. Parts are published at irregular intervals as they become ready, each is complete in itself, available separately, and individually priced. Volumes contain about 300 pages and several volumes may appear within a calendar year. Subscriptions may be placed for one or more of the series on either an Annual or Per Volume basis. Prices vary according to the contents of the individual parts. Orders and enquiries should be sent to: Publications Sales, British Museum (Natural History), Cromwell Road, London SW7 5BD, England. World List abbreviation: Bull. Br. Mus. nat. Hist. (Zool.) Trustees of the British Museum (Natural History), 1984 The Zoology Series is edited in the Museum's Department of Zoology Keeper of Zoology : Dr J. G. Sheals Editor of Bulletin : Dr C. R. Curds Assistant Editor : Mr C. G. Ogden ISBN 565 05004 4 ISSN 0007-1 498 Zoology series Vol 47 No. 1 pp 1-82 British Museum (Natural History) Cromwell Road London SW7 5BD Issued 28 June 1984 BRITISH MUSEUM (NAi JN1984 GE:," Miscellanea Contents A revision of the genera Trachelostyla and Gonostomum (Ciliophora, Hypotrichida), including the redescriptions of T. pediculiformis (Cohn, 1866) and T. caudata Kahl, 1932. By M. Maeda & P. Carey 1 Notes on Atlantic and other Asteroidea. 4. Families Poraniidae and Asteropseidae. By Ailsa M. Clark 19 The larval and post-larval development of the Thumb-nail Crab, Thia scutellata (Fabricius), (Decapoda: Brachyura). By. R. W. Ingle 53 Description of a new species of Sylvisorex (Insectivora: Soricidae) from Tanzania. By P. D. Jenkins 65 A new species of the Hipposideros bicolor group (Chiroptera: Hipposideridae) from Thailand. By J. E. Hill & S. Yenbutra 77 A revision of the genera Trachelostyla and Gonostomum (Ciliophora, Hypotrichida), including redescriptions of T. pediculiformis (Cohn, 1866) Kahl, 1932 and T. caudata Kahl, 1932 Masachika Maeda Ocean Research Institute, University of Tokyo, Nakano, Tokyo 164, Japan Philip G. Carey Department of Zoology, British Museum (Natural History), Cromwell Road, London SW7 5BD Introduction Hypotrich ciliates are commonly encountered in many and diverse habitats. As Corliss (1979) noted, the taxonomy of this group is still confused, indeed some species, genera and even families are awaiting assignment to their proper taxonomic positions. When one genus of hypotrich, Trachelostyla, was isolated from marine interstitial sediments during a previous study of the ciliate fauna of the southern coast of England (Carey & Maeda, 1985), some difficulty was encountered in understanding the taxonomic position of this organism and also the closely related genus Gonostomum. Recent revisions of these two genera by Borror (1972) and Buitkamp (1977) have not clarified their position, they have merely confused the taxonomy of the family Holostichidae by either synonymizing conspicuously different organisms in a single genus or by assigning many disimilar species to one taxon. Since Trachelostyla and Gonostomum have been isolated frequently from marine and terrestrial environments (Kahl, 1932; Gellert, 1956), a detailed taxonomic investigation of these two genera should provide useful information for future ecological studies. This work is intended to clarify the confusion between Trachelostyla and Gonostomum, and by virtue of a complete revision, provide a key to species of these two genera. Additionally the morphological features of Trachelostyla pediculiformis (Cohn, 1866) Kahl, 1932 and T. caudata Kahl, 1932 are redescribed. Materials and methods The hypotrich ciliates were collected from interstitial sediments at East Head, West Wittering, National Grid reference SZ7799, a short headland at Chichester Harbour where, in a previous study, six sampling stations had been established (Carey and Maeda, 1985). Stations 1 and 2 faced the English Channel and were exposed to rather intensive wave action, whereas calmer water prevailed at Stations 4, 5 and 6 at the northern- most extremity of the headland. On the eastern shoreline around Station 6 an extensive saltmarsh was present. Earlier results of sand analysis had indicated that the mean grain size of sand in this area varied between 170 um and 250 um. The 'detrital material' or content of particles less than 62 um increased continuously from Station 1 to Station 6. This component was measured as approximately 100 times higher at Stations 5 and 5 than that at Stations 1 and 2. In October 1982 Trachelostyla pediculiformis was found at all the Stations except Station 1 whereas Trachelostyla caudata was isolated from fine sands with low content of detrital material, i.e. Stations 1, 2 and 3. Water temperature of the sediment was recorded as 14C. Bull. Br. Mm. nat. Hist. (Zool.) 47(1): 1-17 Issued 28 June 1984 2 M. MAEDA & P. G. CAREY In July 1983, the water temperature was 24C and decaying macroalgae were observed in seawater overlying the sampling area. On this occasion T. pediculiformis was found at all Stations sampled (Stations 1, 2 and 3) while T. caudata was encountered only at Station 1. The ciliates were extracted from sediment cores as soon as possible after sampling, by the seawater-ice method of Uhlig (1968). For the sediment sample collected in July 1983, water at low temperature ( 1 2C) was used for extraction instead of crushed ice as the tempera- ture drop killed too many organisms (Hartwig et al., 1977). Samples from each Station were retained in seawater under constant aeration for further investigation. Some difficulty in handling the organisms was experienced due to their thigmotactic nature and inate fragility. Rapid transfer using a wide bore micropipette from extraction dish to glass slide overcame this problem. The ciliates were observed using Nomarski interference, phase contrast and brightfield illumination, and recorded on video tape for repeated observation. High resolu- tion optics and video recording enabled observations to be made on living cells without recourse to silver staining techniques. Nomenclature Faure-Fremiet (1961) proposed the new family Holostichidae in the suborder Stichotrichina to include those organisms which possess a row of right and left marginal cirri, an elongated body and macronuclei two to many in number, with differentiated frontal and transverse cirri in most cases. These characteristics are certainly found in the genera Gonostomum and Trachelostyla although Corliss (1979) suggested the transfer of these two genera to the family Oxytrichidae in the suborder Sporadotrichina, because some members of these taxa have distinctive marginal cirri and well developed fronto ventral and transverse cirri. The genus Gonostomum was proposed by Sterki (1878) who transferred Oxytricha affinis Stein, 1859 to Gonostomum affine because of the location and shape of the peristome area and the arrangement of frontoventral cirri. He also proposed that Oxytricha strenua Engelmann, 1862 be changed to Gonostomum strenua. Since then, these two species have been placed into several genera. Kent (1881-1882) pointed out that the name of Gonosto- mum closely resembled those of Gonostoma and Gonostomus, names already employed to designate certain genera of fish and molluscs. Consequently he proposed the new genus Plagiotricha, with P. affinis and P. strenua. The first detailed revision of this group was presented by Gourret and Roeser (1888), which is illustrated in Table 1. These authors did Table 1 Revision of the genus Stichochaeta by Gourret & Roeser, 1888 Genus Stichochaeta Clap. & Lachm. Syn. Gonostomum Sterki Plagiotricha Sav. Kent 1 . Stichochaeta pediculiformis Cohn Syn. Gonostomum pediculiforme Maupas 2. Stichochaeta affinis (Stein) Syn. Oxytricha affinis Stein Gonostomum affine Sterki Plagiotricha (Gonostomum) affinis Sav. Kent 3. Stichochaeta strenua (Englemann) Syn.Oxytricha strenua Englemann Plagiotricha strenua Sav. Kent Gonostomum strenua Maupas 4. Stichochaeta Corsica n. sp. Stichochaeta Corsica n. sp. CILIOPHORA 3 not accept the names Gonostomum or Plagiotricha and placed the two species mentioned above into the genus Stichochaeta as S. affinis and S. strenua. In their revision, which already contained Stichochaeta pediculiformis described by Cohn, 1866, they also described a new species Stichochaeta Corsica. Maupas (1883) decided to transfer S. pediculiformis to the genus Gonostomum noting that a typical member of this genus Stichochaeta cornuta possessed quite different features in the peristome area and also cirral arrangements from that of Gonos- tomum. In 1929 Shibuya found and described a new species which he named Gonostomum andoi. Kahl in 1928 described G. pediculiforme, but in 1932, in contrast to the description of Maupas (1883), mentioned that certain details were sufficient to erect a new genus, Trachelostyla. He pointed out that the three filose cirri in the caudal area which Maupas (1883) described as caudal cirri were in fact dorsal cirri which can be seen from the ventral side. The discontinuity of the two marginal cirral rows in the posterior area is a characteristic feature of Kahl's description of Trachelostyla. Kahl (1932) placed two species in this genus, T. pediculiformis and a new marine species T. caudata. After the genus Trachelostyla was proposed, the nomenclature of this group became simplified in that only the genera Gonostomum and Trachelostyla were recognized by subsequent authors. T. dubia was described from marine interstitial sediments by Dragesco (1954). In publications dealing with the ciliated fauna in soils underlying moss and leaves, Gellert (1942, 1956, 1957) described 5 species which were attributed to the genus Gonostomum, G. algicola, G. spirotrichoides, G. bryonicolum, G. ciliophorum and G. geleii. The second major revision of this group was presented by Borror (1972) which unfortunately was given without detailed explanations (Table 2). He transferred the 4 species of Gonostomum described by Gellert (1956, 1957) to the genus Trachelostyla along with a species of Urosoma and a species of the genus Sticho- tricha. T. pediculiformis was retained as Kahl (1932) proposed. A major divergence from the established taxonomy was proposed in the removal of Oxytricha affinis; Gonostomum affine of Sterki, 1878 and its synonyms, to the genus Gastrostyla. Trachelostyla dubia Dragesco (1954) was also transferred by Borror (1972) to the genus Gastrostyla. Gonostomum Table 2 Revision of the genera Gonostomum and Trachelostvla by Borror, 1972 Genus Gonostomum Sterki, 1878 1. G. strenum (Englemann, 1862) Sterki, 1978 Syn. Oxytricha strenuum Englemann, 1862 Oxytricha tricornis Milne, 1886 Genus Trachelostyla Kahl, 1932 1. T. pediculiformis (Cohn, 1866) Kahl, 1932 Syn. Stichochaeta pediculiformis Cohn, 1866 S. Corsica Gourret & Roeser, 1887 Gonostomum pediculiforme Maupas, 1883 2. T. bryonicolum (Gellert, 1956) n. comb. Syn. Gonostomum bryonicolum Gellert, 1956 3. T. caudata Kahl. 1932 4. T. ciliophorum (Gellert, 1956) n. comb. Syn. Gonostomum ciliophorum Gellert, 1956 5. T. geleii (Gellert, 1957) n. comb. Syn. Gonostomum geleii Gellert, 1957 6. T. macrostoma (Gellert, 1957) n. comb. Syn. Urosoma macrostoma Gellert, 1957 7. T. simplex (Kahl, 1932) n. comb. Syn. Stichotricha simplex Kahl, 1932 8. T. spirotrichoides (Gellert, 1956) n. comb. Syn. Gonostomum spirotrichoides Gellert, 1956 M. MAEDA & P. G. CAREY Table 3 Revision of the genus Trachelostyla by Buitkamp, 1977 Genus Trachelostyla \. Trachelostyla pediculiformis (Cohn, 1866) Kahl, 1932 Synonym: Stichochaeta pediculiformis Cohn, 1866 Gonostomum pediculiforme Maupas, 1883 S. Corsica Gourret & Roeser, 1887 2. Trachelostyla caudata, Kahl, 1932 3. Trachelostyla affine (Stein, 1859) n. comb. Synonym: Oxytricha affine Stein, 1859 Gonostomum andoi Shibuya, 1929 G. affine (Stein, 1859) Kahl, 1932 G. bryonicolum Gellert, 1956 G. ciliophorum Gellert, 1956 G. spirotrichoides Gellert, 1956 G. geleii Gellert, 1957 Gastrostyla affine (Stein, 1859) Borror, 1972 Trachelostyla bryonicolum (Gellert, 1956) Borror, 1972 T. ciliophorum (Gellert, 1956) Borror, 1972 T. spirotrichoides (Gellert, 1956) Borror, 1972 T. geleii (Gellert, 1957) Borror, 1972 T. canadensis Buitkamp & Wilbert, 1974 strenua, and its synonyms including Oxytricha tricornis Milne (1886-1887) was the only species of this genus to be retained. A new species of Trachelostyla, T. canadensis was described by Buitkamp & Wilbert (1974) from prairie soil in Canada and three years later the last major revision of this group was undertaken by Buitkamp (1977), see Table 3. In the latter revision which was devoid of detailed explanatory information, both Trachelostyla pediculiformis and T. caudata were retained, but an unusual step was taken in the establish- ment of Trachelostyla affine n. comb, and the inclusion of seven species in T. affine under various synonyms. It should be noted that this new taxon contained a variety of morpho- logical forms which, when carefully investigated, should not have been synonymized. The last species to have been described in the genus Gonostomum was G. franzi (1982) from Austrian soils. As a result of these earlier revisions there are still species which have a dubious position in these genera. These include Stichochaeta mereschkoviskii Andrusov, 1886 which Kahl (1932) put forward as a possible Trachelostyla, and Trachelostyla rostrata of Lepsi (1964) which is poorly described. A species of Gonostomum, G. parvum was found and described by Lepsi according to Stiller (1977). However detailed information is not yet available for this species. The diagram of Gonostomum franzi given by Foissner (1982) clearly shows the presence of ventral cirral rows extending almost the full length of the body, and should not be included in the genus Gonostomum. Gonostomum geleii described by Gellert (1957) pos- sesses certain characters that suggest its inclusion in the genus Gonostomum, however the shape of the body and transverse cirri indicate that this organism should be placed in another genus, probably Urosoma. Similarly Borror's (1972) decision to include Urosoma macro- stoma and Stichotricha simplex was clearly based on a superficial resemblance of these organisms to Trachelostyla. However the decision to transfer T. dubia of Dragesco (1954) to the genus Gastrostyla in our opinion was correct. A detailed study of these organisms indicates that they should all be excluded from the genus Gonostomum. Jankowski (1979) proposed a new scheme of classification for the order Hypotrichida, including the trans- ference of the genus Trachelostyla to the new subfamily Oxytrichinae. But as detailed infor- mation on these revisions were not given, the Jankowskian scheme of classification was not followed in the present work. CILIOPHORA 5 Although 3 major revisions have been undertaken on this group, little information has been given by authors in support of major taxonomic changes. Certainly with the confusion regarding these genera it is clearly essential that a complete and accurate revision should be undertaken. Diagnosis of the Genus TRACHELOSTYLA Kahl, 1932 Gonostomum Maupas, 1883 pro pane Stichochaeta Gourret & Roeser, 1888 pro pane A free swimming genus of hypotrich with a fragile and elastic, but non-contractile body, 130-1 90 um in length. This organism possesses a narrow neck-like constriction in the anterior region. The peristome area is confined to the left lateral border, its posterior part bending abruptly and extending nearly to the centre of the body. Five to 10 frontoventral cirri are present in the anterior region, but frontoventral cirri in the mid- and posterioventral area are absent. Five or six transverse cirri are distinct in the posterior and form an oblique row. There are two marginal cirral rows which are not confluent posteriorly. No caudal cirri are present. Fine dorsal cirri can be observed from the ventral side. These appear to make two rows at the edge of the body and where these terminate at the posterior end some authors in earlier descriptions have clearly misinterpreted these as caudal cirri. Numerous macro- nuclei are dispersed throughout the body. This genus is found in marine habitats, and may be described as truely interstitial. Key to species of Trachelostyla Posterior region rounded, membranelles of AZM thickened and distinctive . . . . pediculiformis Posterior region narrowed, membranelles of AZM fine and of uniform length caudata Trachelostyla pediculiformis (Cohn, 1866) Kahl, 1932 Stichochaeta pediculiformis Cohn, 1866 Gonostomum pediculiforme Maupas, 1883 Stichochaeta Corsica Gourret & Roeser, 1888 MORPHOLOGICAL DESCRIPTION: This species was found in interstitial sediments at East Head, Chichester Harbour, England, during a taxonomic and ecological survey of marine inter- stitial ciliates, in October, 1982 and July, 1983 (Carey & Maeda, 1985). Water temperatures of the sediment were 14C and 24C, respectively. This highly psammophilic species has been commonly encountered in many coastal areas of Europe, Russia, North and South America and the Sea of Japan. The body is characteristically flexible. Its locomotion as well as its body shape is distinct enough to distinguish it from other ciliates, frequently moving forward and backward and repeatedly raising the 'head' region above the substrate, con- stantly searching between the sand grains. The body is elongate, 136-196 um in length (Fig. 1). The anterior region, which comprises one-third of entire body length, is attenuated and produced as a narrower neck-like process. The posterior end is rounded in this species. The peristome area is confined to the left lateral border of the anterior region for most of its length. The posterior quarter of peristome area is bent inwards, and eventually extends to near the centre of the body. The buccal opening is situated at the 'shoulder-like' ridge at the base of the 'neck' region. There are five long membranelles of the AZM at the anterior extremity. A bundle of several long cilia-like mem- branelles are clearly seen in the buccal area which is entirely consistent with Cohn's (1866) published diagram. The very thin, membrane-like dorsal edge of the peristome extends for half the total length of the AZM on the left side. These are transparent and easily overlooked. The anterior area displays three frontal and seven ventral cirri. Maupas (1883), Kahl (1932) and Borror (1972) indicated the number of these cirri as 8, 1 1 and 11, respectively, including M. MAEDA & P. G. CAREY AZM DC TC Fig. 1 Trachelostyla pediculiformis Entire organism, ventral view, (AZM) adoral zone of mem- branelles, (FC) frontal cirri, (VC) ventral cirri, (MC) marginal cirri, (TC) transverse cirri, (DC) dorsal cirri, (BC) buccal cavity, (Ma) macronuclei. Bar represents 10 urn. three distinct frontal cirri. There are no ventral cirri in the middle and posterior of the body as Kahl (1932) described. However in the descriptions of Maupas (1883) and Borror (1972) two ventral cirri just anterior of transverse cirri were present. Five or sometimes six trans- verse cirri make an oblique row from the left hand to the right hand side of the body. The right marginal cirral row starts from the 'shoulder' adjacent to the apical area and left row runs from just below the buccal region. These two marginal rows are not confluent poster- iorly and terminate at the base of the transverse cirri. At both lateral edges rows of very CILIOPHORA 7 fine and long cilia can be observed, they are particularly long in the posterior region. Maupas (1883) designated these long cilia at the posterior end as caudal cirri, however Kahl (1932) found them projecting from the dorsal surface of the body: that is to say these thread-like cilia of the lateral and posterior are bristles originating from the dorsal side. Cohn (1866) found this species and appointed the name Stichochaeta pediculiformis. Maupas (1883) also described this organism and transferred it to the genus Gonostomum as G. pediculiforme because he found it had quite different morphological features in the peristome area, and cirral arrangements from the genus Stichochaeta of Claparede & Lachmann (1858), Kahl redescribed G. pediculiforme in 1928. However, he erected the new genus Trachelostyla in 1932 giving the reason that the organism had a 'neck-forming' narrowed peristome area and its two marginal cirral rows were not confluent at the posterior end of the body. He included two species in this genus, T. pediculiformis and T. caudata. Borror (1972) and Buitkamp (1977) agreed with Kahl (1932) and placed Gonostomum pediculiforme and Stichochaeta pediculiformis as synonyms of T. pediculiformis. In agreement with Kahl (1932), Borror (1972) and Buitkamp (1977), the possession of a narrowed 'head' area, clearly denned transverse cirri, the non-convergent marginal cirral rows posteriorly and the absence of caudal cirri are sufficient reason to retain this species in the genus Trachelostyla. Gourret & Roeser (1 888) described Stichochaeta Corsica as having serried rows of adoral 'cirri', long and fine caudal 'cilia', dorsal 'cilia' and transverse cirri. Careful analysis of their description and diagram reveals the long and fine cilia at the pos- terior extremity of the body are in reality dorsal bristles, not caudal cirri. From a detailed survey of morphological features it is clear that S. Corsica must be considered a synonym of T. pediculiformis. Trachelostyla caudata Kahl, 1932 MORPHOLOGICAL DESCRIPTION: Specimens were found in the fine sediments of East-Head, Chichester Harbour, especially in sands which contained a lower content of detrital material than the chosen biotope of Trachelostyla pediculiformis (Carey & Maeda, 1985). The dates of sampling and the water temperature of the sampling area were the same as that for T. pediculiformis. This psammophilic species was reported to be common in the coastal areas of many European countries and Russia. Locomotion is similar to T. pediculiformis, but the 'head region' is not lifted from the substrate during forward movement. The body, 1 56 urn in length, is fragile and elastic but not contractile (Fig. 2). It is elongated and has a narrowed 'neck-like' anterior and a narrowed 'tail-like' posterior region. The form of peri- stome area is similar to T. pediculiformis which is confined to the left lateral border of the 'head' area, and its posterior bends abruptly, extending backwards to near the centre of the body. Five long membranelles of the AZM are present at the apex of the cell, but the mem- branelles of the lateral portion are rather short and 'brush-like'. The characteristically long membrane which T. pediculiformis possesses in the buccal area is not present in this species. Among the four fronto ventral cirri, 3 make a row, but the fourth cirrus from the apex is slightly separated from the other three. The length of these cirri is approximately the same as that of the marginal cirri. There are no frontoventral cirri in the mid- and posterioventral area. Five thick transverse cirri are present, as Kahl (1932) described, these make a oblique row from the left to the right hand side. The right marginal cirral row starts from the base of the narrowed 'head' and the left marginal row begins just posterior of the end of the peri- stome. The two marginal rows terminate at the base of the transverse cirri. At both the right and left edges of the body, faint dorsal cilia are clearly displayed. These dorsal cilia of the right hand edge run from the top of the apical area, and join the other dorsal row of cilia of the left hand side at the posterior end of the body. Dorsal cilia or cirri are not as long as those of T. pediculiformis and do not extend to any great length in the caudal area. There are 8-10 dorsal cirral rows according to Kahl (1932). A contractile vacuole is situated just posterior of the peristome end. In Kahl's (1932) diagram, 11 macronuclei are shown. M. MAEDA & P. G. CAREY Fig. 2 Trachelostyla caudata Ventral view. Bar represents 10 ^m. This animal was originally found in the sands of Kiel by Kahl (1932). In agreement with both Borror (1972) and Buitkamp (1977) this organism has been retained in the genus Trachelostyla. Diagnosis of the Genus GONOSTOMUM Sterki, 1878 Oxytricha Stein, 1859 pro pane Plagiotricha Kent, 1881-1882 Stichochaeta Gourret & Roeser, 1888 pro pane Gastrostyla Borror, 1972 pro pane Trachelostyla Borror, 1972 pro pane 9 CILIOPHORA 9 A genus of hypotrich with a more or less flexible and elastic, but non-contractile body. The body shape is oval or ellipitical, 60-1 50 um in length. The peristome area is confined to the lateral border and its posterior portion, in most cases, is abruptly bent towards the centre of the body. The AZM in the apical area is composed of long and thick membranelles. There are 3 distinct frontal cirri in the anterior region. Among the 6 to 20 ventral cirri present, one or two cirri are positioned just anterior of the transversals. No ventral cirri are present in the mid-ventral area. Two to four transverse cirri are present, which are not thickened in most species. There are two marginal cirral rows which are confluent posteriorly, or more correctly run posteriorly to meet several elongate caudal cirri. Dorsal cirri are not long enough to be seen from the ventral side of the body. Two oval macronuclei are present and a single micronucleus is situated near each of the macronuclei. A single contractile vacuole is situated just posterior of the end of the peristome area, at the left hand lateral border. The species belonging to this genus are found in salt water, fresh water and terrestrial soils. Key to species of Gonostomum 1 Ventral cirral rows well developed 2 Ventral cirral rows absent 4 2 At least one ventral cirral row extending further than the end of the peristome. strenua Ventral cirral rows terminating at the peristome 3 3 Four transverse cirri present affine Two transverse cirri present algicola 4 Caudal cirri present 5 Caudal cirri absent ciliophorum 5 AZM bent abruptly inwards at the buccal cavity, membranelles large and distinctive . . bryonicolum AZM gently curved inwards at the buccal cavity, membranelles not distinctive. . . . spirotrichoides Gonostomum affine (Stein, 1859) Sterki, 1878 Oxytricha affinis Stein, 1859 Plagiotricha affinis Kent, 1881-1882 Stichochaeta affinis Gourret & Roeser, 1888 Gonostomum andoi Shibuya, 1929 Gastrostyla affine Borror, 1972 Trachelostyla affine Buitkamp, 1977 DIAGNOSIS: This free swimming species has been found in a variety of habitats including salt water, soil under leaf litter, moss and heathland. The length recorded by Kahl (1932) was 95-1 15 um, however those of Wenzel (1953) were measured as 63-125 um. The body is elongate and its anterior and posterior ends are narrowed and slightly pointed (Fig. 3). Kent (1881-1882) described the body form as lanceolate. The peristome area is arcuate and is confined chiefly to the left lateral side, its posterior end bending inwards at the tip, terminating near the centre of the body. There are three frontal cirri in the anterior area and one buccal cirrus above the paroral membrane. According to Buitkamp (1977) there is one distinct frontal cirrus in the apical region, but Foissner (1982) in his detailed investi- gation found 3 frontal cirri as Stein (1859), Kent (1881-1882) and Kahl (1932) described. The ventral cirri number 8 to 13 in Stein's (1859) diagram, some of these making a slightly oblique row on the right side of the peristome. There are only 2 ventral cirri in the mid- ventral area, placed just in front of the transverse cirri. Three to five transverse cirri are present, whose length does not extend beyond the posterior end of the body in the original description. However, Kahl (1932), Wenzel (1953) and Foissner (1982) showed this animal having rather longer transverse cirri than those described by Stein (1859). Two marginal cirral rows are confluent posteriorly or terminate as a row of caudal cirri in some descriptions (Wenzel, 1953; Buitkamp, 1977). Two macronuclei are present. A contractile vacuole is situated just below the peristome. 10 M. MAEDA & P. G. CAREY Fig. 3 Gonostomum affine After Wenzel, 1953; ventral view slightly modified. Bar represents 10 ^m. This animal was described by Stein (1859) and given the name Oxytricha affinis. Sterki (1878) noted the characteristic shape of the peristome area and the lack of mid-ventral cirri. In consequence he erected the new genus Gonostomum and transferred O. affinis to G. affine. Kent (1881-1882) pointed out that the name of Gonostomum closely resembled that of Gonostoma and Gonostomus which were already employed to designate certain genera of fish and molluscs. Consequently Kent appointed the new genus Plagiotricha which included P. affinis. Gourret & Roeser (1888) agreed with the action of Kent, but chose to transfer P. affinis to the genus Stichochaeta. Gonostomum andoi Shibuya, 1 929 possesses a slightly different arrangement of cirri on the ventral surface from that of G. affine: that is, it displays a slightly higher number of frontoventral cirri and no cirri just anterior of transversals. But Kahl (1932) and Buitkamp (1977) showed the variation of form in G. affine especially the absence of ventral cirri just anterior of the transverse. Because other features of this organism resemble those of G. affine, we designate G. andoi as the synonym of G. affine. Kahl (1932) retained this organism as Gonostomum affine and gave Gonostomum andoi as its synonym. Borror (1972) transferred this organism to Gastrostyla affine because it possessed one oblique row of ventral cirri. However it is clear that this ventral cirral row in Gonostomum affine is not sufficiently developed to ensure removal to the genus Gastrostyla. Buitkamp (1977) proposed the new combination Trachelostyla affine, however Foissner (1982) retained this species in the genus Gonostomum. CILIOPHORA 1 1 In agreement with Kahl (1932) and Foissner (1982), the confluence of the 2 marginal cirral rows (Stein, 1859), the possession of caudal cirri (Wenzel, 1953), the presence of two ventral cirri just anterior of the transversals and 2 macronuclei are sufficient to retain this organism in the genus Gonostomum. Gonostomum strenua (Engelmann, 1862)Sterki, 1878 Oxtricha strenua Engelmann, 1862 Plagiotricha strenua Kent, 1881-1882 Stichochaeta strenua Gourret & Roeser, 1888 DIAGNOSIS: This organism has a flexible and contractile form, the body being elongate and elliptical (Fig. 4). It has been described from fresh water. The length recorded by Engelmann was 1 50 jim. Its anterior and posterior ends are evenly rounded. The frontal region is slightly thinner and dorsoventrally thicker than the posterior area. The peristome area is very narrow and confined to the left hand lateral edge, its posterior end being inwards, extending nearly to the centre of the body. The adoral zone of membranelles in the lateral area of the peri- stome is longer than that of Gonostomum affine. There are 23-25 frontoventral cirri, most of which form two slightly oblique rows, one row extending two thirds of the total body length, the other row being only half as long. No frontoventral cirri are present in front of the 4 transverse cirri. We assume that among the transverse cirri, possibly two can be counted Fig. 4 Gonostomum strenua After Englemann, 1862; ventral view. Bar represents 10 ^im. 12 M. MAEDA & P. G. CAREY as frontoventrals. The right and left marginal cirri were confluent posteriorly. At the posterior extremity there were 4 long, fine caudal cirri. Two macronuclei are present in the midventral area and one contractile vacuole is situated just below the peristome. Englemann (1862) first described this organism under the name Oxytricha strenua. Sterki (1862) established the new genus Gonostomum and transferred O. strenua to G. strenua on the same basis that O. affinis was transferred to G. affine (see species description, G. affine). Kent (1881-1882) erected the new genus Plagiotricha and proposed P. strenua, and Gourret and Roeser (1888) transferred this organism to Stichochaeta strenua. Kahl (1932) and Stiller (1974) redescribed it as G. strenuum and G. strenua, respectively. Borror (1972) retained only G. strenua in the genus Gonostomum and adopted Oxytricha tricornis Milne, 1886-1887 as its synonym. After careful study of the original description and diagram of O. tricornis it is clear that it should be excluded from Gonostomum and from Oxytricha because of the unusual form taken by peristome. Gonostomum algicola Gellert, 1 942 Trachelostyla canademis Buitkamp & Wilbert, 1974 Trachelostyla affine Buitkamp, 1977. DIAGNOSIS: This species was found in association with green plants on rocks, feeding on flagellates. The length has been recorded as 60-100 um. The body displays an oval or ellipti- cal shape (Fig. 5). The peristome area is confined to the left lateral border and the AZM Fig. 5 Gonostomum algicola After Gellert, 1942; ventral view. Bar represents 10 u CILIOPHORA 13 extends backwards to nearly half the body length. A quarter of the peristome is bent inwards toward the body. In the frontal area 10 thick cirri are usually observed, including 3 frontal cirri and 1 buccal cirrus. Five ventral cirri make a slightly oblique row in the frontal region. Mid- ventral cirri are absent. Transverse cirri number two and there are two caudal cirri pre- sent. There are 1 5 left marginals and 1 8 right marginals. Two macro- and two micronuclei are present. These features are characteristic of the genus Gonostomum. Buitkamp and Wilbert (1974) isolated Trachelostyla canadensis from prairie soil in Canada. Buitkamp (1977) transferred this species to T. affine in his revision of the genus Trachelostyla. The presence of 3 frontal cirri, 1 buccal cirrus, 2 transverse cirri and 2 macro- nuclei, also the lack of ventral cirri in the mid- ventral area indicate this species has a strong similarity to that of Gonostomum algicola although there are 2 caudal cirri instead 3 in G. algicola. These taxonomic features are clearly sufficient to designate this animal as the synonym of G. algicola. Gonostomum spirotrichoides Gellert, 1956 Trachelostyla spirotrichoides Borror, 1972 Trachelostyla affine Buitkamp, 1977 DIAGNOSIS: This species has been found in soil under moss, feeding on bacteria and detritus. The body length is 1 10 um and its form is elongate and cylindrical (Fig. 6). The peristome Fig. 6 Gonostomum spirotrichoides After Gellert, 1956; ventral view. Bar represents 10 um. 14 M. MAEDA & P. G. CAREY region is confined to the left lateral edge and extends backwards to nearly the centre of the body. The AZM comprises 27 membranelles of which 4 membranelles in the apical area are distinctly longer than others. The buccal opening is situated at the posterior extremity of the AZM, which displays a funnel like appearance. There are 3 distinct frontal cirri at the apex of the cell. Among the five ventral cirri present, three cirri are arranged in one oblique row extending from the right to the left of the body. It is not certain whether one cirrus which is situated below the end of this cirral row, is a buccal cirrus. Two isolated cirri are present at the region just below the majority of the ventrals and there is another pair of ventral cirri just in front of the 4 transversals. The number of right marginal cirri is 19, left marginal cirri number 15. Between the two marginal cirral rows there are four caudal cirri situated at the posterior. On the dorsal surface, three cirral rows of long bristles have been described. Two macronuclei with one micronucleus are present at the fronto- and midventral areas, respectively. A contractile vacuole is situated at the left of the posterior end of the AZM. Because of the possession of caudal cirri, the presence of two ventral cirri just anterior of the transversals and two macronuclei, Borror (1972) was clearly in error in attributing this animal to the genus Trachelostyla, as T. spirotrichoides. Buitkamp's (1977) designation of the new combination Trachelostyla affine is also incorrect. Based on the present study this species has been retained in the genus Gonostomum, as G. spirotrichoides. Fig. 7 Gonostomum bryonicolum After Gellert, 1956; ventral view. Bar represents 10 (im. CILIOPHORA 15 Gonostomum bryonicolum Gellert, 1956 Trachelostyla bryonicolum Borror, 1972 Trachelostyla affine Buitkamp, 1977 DIAGNOSIS: The ciliate was found in the humus layer of soil samples and has been desig- nated a detritus feeder, 60 urn, in length. The body is oval, cylindrical and the peristome region is arcuate and confined chiefly to the left lateral border, consequently its posterior end bends abruptly inwards, terminating near the centre of the body where the buccal appar- atus is situated (Fig. 7). In the anterior region there are 3 distinct frontal cirri and 4 ventral cirri, behind which are a separate pair of ventral cirri. One buccal cirrus is situated just above the anterior- most end of the paroral membrane. There is only one ventral cirrus in the midventral area, placed just in front of the four transverse cirri. Two marginal cirri rows terminate as a group of four caudal cirri at the posterior. Four cirral rows of long bristles on the dorsal side have been described. Two macronuclei are present together with one micronucleus, and one contractile vacuole is situated near the termination of the peristome. Borror (1972) and Buitkamp (1977) transferred this species to the genus Trachelostyla as T. bryonicolum and T. affine, respectively. The existence of caudal cirri and a ventral cirrus just anterior of the transversals, indicate that it should be retained in the genus Gonostomum as G. bryonicolum. Fig. 8 Gonostomum ciliophorum After Gellert, 1956: Ventral view. Bar represents 10 (im. 16 M. MAEDA & P. G. CAREY Gonostomum ciliophorum Gellert, 1956 Trachelostyla ciliophorum Borror, 1972 Trachelostyla affine Buitkamp, 1977 DIAGNOSIS: This species has been described as a bacteria and detritus feeder, and was found in the humus layer of soil. The body, 70 um in length, displays a slender and oval form (Fig. 8). The peristome area is confined chiefly to the left lateral border, its posterior portion bending inwards into the body. The buccal apparatus is located at the posterior end of the AZM. Three distinct frontal, one buccal and seven ventral cirri are present on the right of the peristome. There are two ventral cirri in the posterioventral area placed just anterior of the transverse. There are four transverse cirri, two of which were longer than the others. Two marginal cirral rows are confluent posteriorly where no caudal cirri are situated. Two macronuclei with one micronucleus are present, one at the front and the other in the midventral area. Without detailed comments, Borror (1972) transferred this species to the genus Trachelo- styla as T. ciliophorum and Buitkamp (1977) proposed the new combination Trachelostyla affine, again with scant information. Here it has been retained in the genus Gonostomum, as G. ciliophorum despite the revision of Borror (1972) and Buitkamp (1977) who clearly did not take into account the presence of confluent marginals and other diagnostic features. References Andrusov, V. J. 1886. Infusoria of the Bay of Kertch. Trudy Imperatorskago Sankt-Peterburgskago Obschchestva Estestvoispytatelei. S.-Peterburg. (Leningrad) 17: 236-259. Borror, A. C. 1963. Morphology and ecology of the benthic ciliated protozoa of Alligator Harbor, Florida. Achivfur Protistenkunde 106: 465-534. 1972. Revision of the order Hypotrichida (Ciliophora, Protozoa). Journal of Protozoology 19: 1-23. Buitkamp, U. 1977. Uber die Ciliatenfauna zweier mitteleuropaischer Bodenstandorte (Protozoa; Ciliata). Decheniana (Bonn) 130: 1 14-126. & Wilbert, N. 1974. Morphologic und Taxonomie einiger Ciliaten eines kanadischen Prariebo- dens. Acta Protozoologica 13: 201-210. Carey, P. G. & Maeda, M. 1985. Horizontal distribution of psammophilic ciliates in fine sediments of the Chichester Harbour area. Journal of Natural History (in press). Claparede, E. & Lachmann, J. 1857. Etudes sur les infusoires et les rhizopodes. Memoires de I'lnstitut National Genevois 5: 1-260. Cohn, F. 1866. Neue Infusorien im Seeaquarium. Zeitschrift fur wissenschaftliche Zoologie 16: 253-302. Corliss, J. O. 1979. The Ciliated Protozoa: Characterisation, Classification and Guide to the Litera- ture. 2nd ed. Oxford: Pergamon, 455 pp. Dragesco, J. 1954. Diagnoses preliminaires de quelques cilies nouveaux des sables. Bulletin de la Societe Zoologique de France. Paris 79: 62-70. Engelmann, T. W. 1862. Zur Naturgeschichte der Infusionthiere: Beitrage zur Entwicklungsgeschichte der Infusorien. Zeitschrift fur Wissenschaftliche Zoologie. Leipzig 11: 347-393. Faure-Fremiet, E. 1961 . Remarques sur la morphologic comparee et la systematique des Ciliata Hypo- trichida. Comptes Rendus Hebdomadaires des Seances de I 'Academic des Sciences. Paris 252: 3515-3519. Foissner, W. 1982. Okologie und Taxonomie der Hypotrichida (Protozoa: Ciliophora) einiger osterrei- chischer Boden. Archivjur Protistenkunde 126: 19-143. Gellert, J. 1942. Eletegyuttes a fakereg zaldporos bevonataban. Acta Scientiarum Mathematicarum et Naturalium, Universitas Francisco- Josephina Kolozsvdr 8: 1-36. 1956. Ciliaten des sich unter dem Moosrasen auf felsen gebildeten Humus. Acta Biologica, Academiae Scientiarum Hungaricae 6: 337-359. 1957. Ciliatenfauna im Humus einiger ungarischen Laub- und Nadelholzwalder. Annales Instituti Biologici (Tihany) Hungaricae Academiae Scientiarum 24: 1 1-34. CILIOPHORA 1 7 Gourret, P. & Roeser, P. 1888. Contribution a 1'etude des Protozoaires de la corse. Archives de Biolo- gie. Paris 8: 1 39-204. Hartwig, E., Gluth, G. & Weiser, W. 1977. Investigations on the ecophysiology of Geleia nigriceps (Ciliophora, Gymnostomata) inhabiting a sandy beach in Bermuda. Oecologia (Berlin) 31: 1 59-1 75. Jankowski, A. W. 1 979. Systematics and phylogeny of the order of Hypotrichida Stein, 1 859 (Protozoa, Ciliophora). Trudy Zoologicheskogo Instituta, Akademiya Nauk SSSR, Leningrad 86: 48-85. Kahl, A. 1928. Die Infusorien (Ciliata) der Oldesloer Salzwasserstellen. Archiv fur Hydrobiologie 19: 189-246. 1932. Urtiere oder Protozoa I. Wimpertiere oder Ciliata (Infusoria) III. Spirotricha. In Dahl, F. (Ed.) Die Tierwelt Deutschlands und der angrenzenden Meeresteile 25: 399-650. Gustav Fisher, Jena. Kent, W. S. 1881-1882. A Manual of the Infusoria, 2. David Bogue, London, 473-913. pp. Lepsi, I. 1962. Uber einige insbesondere psammobionte Ciliaten vom rumanischen Schwarzmeer-Ufer. Zoologischer Anzeiger. Leipzig 168: 460-465. Maupas, E. 1883. Contribution a 1'etude morphologique et anatomique des infusoires cilies. Archives de Zoologie Experimental et Generate (serie 2) 1: 427-664. Milne, W. 1886-1887. On a new tentaculiferous protozoon and other infusoria, with notes on repro- duction and the function of the contractile vesicle. Proceedings of the Philosophical Society of Glasgow 18: 48-56. Stein, F. 1859. Der Organismus der Infusionsthiere nach eigenen Forschungen In Systematischer Reihenfolge Bearbeitet I. Leipzig, 206 pp. Sterki, V. 1878. Beitrage zur Morphologic der Oxytrichinen. Zeitschrift fur Wissenschaftliche Zoolo- gie. Leipzig (ser. 3) 31: 29-58. Shibuya, M. 1929. Notes on two Hypotrichous ciliates from the soil. Proceedings of the Imperial Academy of Japan, Tokyo 5: 155-156. Stiller, J. 1974. Jarolabacskas csillosok-Hypotrichida. Magyarorszdg Allatvildga Fauna Hungariae 115: 1-189. Uhlig, G. 1964. Eine einfache Methode zur Extraktion der vagilen, mesopsammalen Mikrofauna. Helgoldnder Wissenschafterliche Meeresuntersuchungen. Helgoland 111: 178-185. Wenzel, F. 1953. Die Ciliaten der Moosrasen trockner Standorte. Archiv fur Protistenkunde 99: 70-141. Manuscript accepted for publication 23 September 1983. Notes on Atlantic and other Asteroidea. 4. Families Poraniidae and Asteropseidae Ailsa M. Clark Department of Zoology, British Museum (Natural History), Cromwell Road, London SW7 5BD Introduction The skeletal structure of the poraniid starfishes, upon which the classification relies, is hidden or at least obscured by the more or less thickened body wall and opaque skin. X-radiographs of some North Atlantic specimens have thrown new light on the limits of several taxa. The study has been helped by additional material, from various museums and oceanographic institutes, notably from recent collections of the Discovery, RSS Challenger, Walter Herwig and Alvin, as well as many type specimens. Two inter- family transfers of genera are also made: the Southern Ocean genus Poraniopsis Perrier hitherto placed in the Echinasteridae despite its name is now included in the Poraniidae while conversely Poraniella Verrill is transferred from the Poraniidae to the Asteropseidae. In view of previous confusion between these two families, the paper is prefaced by full diagnoses of both. A tabular key for characters of the genera of Poraniidae is appended. Systematic Account Family ASTEROPSEIDAE Hotchkiss & Clark Asteropsidae Perrier, 1884: 154. Gymnasteriidae (pt) Sladen, 1889: 355-356; Perrier, 1894: 327. Asteropidae Fisher, 1908: 90; 1911 (pt): 247-248; Verrill, 1915: 86. Poraniidae (pt) Spencer & Wright, 1966: U69. Asteropseidae Hotchkiss & A. M. Clark, 1976: 266; Blake, 1980: 179; 1981: 381, 391. A family of the order Valvatida with body form stellate, but the young nearly pentagonal, interradial arcs rounded or sometimes with a blunt angle; arms normally five, flat below, convex or carinate above, there being a distinct ventrolateral angle, entirely covered by more or less thickened skin, opaque and tending to obscure the skeleton in larger specimens, R>20mm; abactinal skeleton with primary calycinal plates usually distinguishable, small specimens with compact, flat, initially rounded or hexagonal somewhat imbricating plates (as in the Atlantic genus Poraniella which is only known at R<20 mm) arranged in longi- tudinal series but becoming an open reticulum with linking secondary plates, armed with single carinal spines only (Asteropsis), spaced fine spines (Poraniella), numerous spines (Valvaster) or completely spineless (other genera); abactinal papulae single in small speci- mens but becoming grouped in the skeletal meshes in larger ones; marginal plates well developed, inferomarginals thick wedge shaped, usually projecting to form a ventrolateral angle, variously armed to match the abactinal armament (Poraniella with a horizontal fringe of divergent spines along the edge and a few smaller ones above), superomarginals usually bare and more or less inset but with a few small spines in Poraniella or with multiple spines and often a conspicuous pedicellaria in Valvaster; actinal plates in longitudinal series parallel to the ambulacra, the largest plates and longest series adradial, naked or armed with a few spaced spines; adambulacral plates with two series of spines sheathed in thick skin: pedi- cellariae present in some species, granuliform or (in Petricia and Valvaster) large bivalved Bull. Br. Mm. nat. Hist. (Zool.) 47(1): 19-51 Issued 28 June 1984 19 20 A. M. CLARK (Valvaster also having some elongated tong shaped ones): internally interbrachial septa pre- sent and reinforced by a proximal vertical calcined column in each interradius, joined to the side wall of the disc by a membrane (in Asteropsis at least; septum present but undescribed by Fisher, 1911 in Dermasterias and in Valvaster by Blake, 1980). DISCUSSION: In distinguishing between the Asteropseidae and Poraniidae in 1976, Hotchkiss & Clark (p. 266) failed to realize that Poraniella Verrill, 1914 (then unrepresented in the British Museum collections) shares the arrangement of the series of actinal plates parallel to the furrow characteristic of the Asteropseidae, to which this west indian genus is now referred from the Poraniidae as the only Atlantic representative of an otherwise Indo-Pacific family. All the known specimens of Poraniella are small, whereas the other asteropseids may exceed 70 mm or even 100 mm R. In comparison of a Poraniella echinulata (Perrier) (from the Pillsbury collections in the Lesser Antilles) with a small Asteropsis carinifera (Lamarck) (from the Indian Ocean), both R c. 10 mm, the abactinal plates are similarly arranged in longitudinal rows and hexagonal in shape, though with slightly better developed and more imbricating lobes in Poraniella where there is a well developed armament of fine spaced spinelets or spines on the abactinal, marginal and actinal plates missing in the Asteropsis. Both have the five primary radial plates distinctly enlarged at the head of the midradial series of plates which form a keel in the Poraniella whereas, surprisingly, the rays are quite flat in the small Asteropsis though keeled in larger ones. Also the superomarginals of the small Asteropsis completely overlie the inferomarginals, rather than being inset as in Poraniella, and each bears a relatively stout tubercular spine and some smaller tubercles, though in large Asteropsis these plates are inset and usually naked. The skin investment is thicker throughout in the Asteropsis but the wet preservation (the Poraniella is dry) may account for the difference. Because of the general resemblance of the plating at some stage of the ontogeny, I do not think that the difference in armament and apparently thinner skin in the Poraniella merit more than a generic difference, justifying its inclusion in the Asteropseidae. Indeed, Poraniella is intermediate in armament and skin between Asteropsis and Valvaster, support- ing Blake's inclusion of Valvaster in the family in 1980. Family PORANIIDAE Perrier Poraniidae Perrier, 1893: 849; 1894: 163-164; Verrill, 1914: 17; 1915: 68; Mortensen, 1927: 89-90; Fisher, 1940: 154; Spencer & Wright, 1966 (pt): U69; Hotchkiss & Clark, 1976: 263-266; Blake, 1981:380-381. Gymnasteriidae: Bell, 1893: 21, 78; Farran, 1913: 16. Asteropidae (pt) Fisher, 1911: 247-248. Asteropidae: Koehler, 1921: 40-41; Mortensen, 1933: 249: Fisher, 1940: 136. A family of normally five-rayed Valvatida with body form short-rayed stellate or almost pen- tagonal, interradial arcs rounded, or sometimes angular (in Poraniopsis and some Poranio- morpha); upper side arched, under side flat or, if the body is cushion shaped, slightly convex, a ventrolateral angle more or less distinct; dorsal body wall thickened and skin opaque in all but the smallest specimens; abactinal plates obscured or concealed, when well developed either similar and forming an irregular fairly compact reticulum (Poraniomorpha) or with the ten primary calycinal plates on the disc enlarged and making a pentaradiate pattern from which run irregular carinal (midradial) series of plates linked to the superomarginals by transverse chains of dorsolateral plates sometimes interconnected to form an open reticulum with larger nodal plates (Porania and Poraniopsis), but in some taxa the plates progressively resorbed internally, even completely lost in large specimens, R> 50 mm, and the body wall more or less thickened to give compensatory support, gross armament usually lacking or sparse, only Poraniopsis and occasional Porania with coarse spaced spines on some of the larger plates, sometimes the skin of the upper side with more or less numerous spiniform, papilliform or almost granuliform spinules, forming a continuous coating, rarely even finer ASTEROIDEA 2 1 spicules, this superficial armament not necessarily penetrating the soft tissue to contact the underlying plates; papulae either spaced or clustered, often present intermarginally as well as abactinally; marginal plates either well developed together with the abactinal skeleton (though often becoming hollow) or sharing in general decalcification, when well developed the two series tending to alternate and often flattened in planes at right angles, the infero- marginals then horizontal and alone supporting the venterolateral angle, the superomarginals vertical (e.g. in Poranid) or both series more compact, blocklike, sharing in forming the ambitus, the angle less well marked (Poraniomorpha], or the plates relatively undistinguished except for their longitudinal arrangement, the inferomarginals ventrally aligned and without a distinct angle (Poraniopsis), inferomarginals armed with a horizontal series, sometimes enclosed within the body wall or more or less aborted (Porania and Chondraster), or with multiple spinules usually enlarged into spinelets along the maximum convexity (Poranio- morpha), or with a few coarse spines not forming a horizontal series (Poraniopsis); actinal areas large, the plating obscured by thick skin usually with spaced grooves which sometimes fork or anastomose running from furrow to margin, or pustular, the underlying plates pri- marily arranged in arcs parallel to the margin, the longest series admarginal (abradial), the shortest adoral, spanning the interradius, also forming series corresponding to the grooves, if the skeleton is generally reduced then the actinals are progressively resorbed from within, appearing as rings on the inner face of the body wall of dissected specimens, the last traces of them close to the adambulacrals, actinal surface either naked or armed with a few spaced spines arising from the underlying plates tending to form series parallel to the margin, or with spinelets enlarged from spinules, spinules alone or unarmed; adambulacrals armed with a few sheathed furrow and subambulacral spines, aligned either transversely (e.g. Porania) or longitudinally (Chondraster and Poraniomorpha); pedicellariae unknown; internally interbrachial septa developed, reinforced by vertical plating unless the entire skeleton is reduced. DISCUSSION: Hotchkiss (in Hotchkiss & Clark, 1976: 265-266) was largely responsible for emphasizing the importance of the different arrangement of the actinal plates with the pri- mary series either parallel to the margin as in the Poraniidae, or parallel to the furrow as in the Asteropseidae. The two families are also probably distinguishable by thermal differ- ences since the Asteropseidae are found in shallow water in tropical or warm-temperate seas while the Poraniidae are mainly from cold temperate and boreal seas, only occurring in lower latitudes at greater depths and with a stunted form. This accords with the removal now from the Poraniidae to the Asteropseidae of the west indian Poraniella Verrill, 1914, because of the actinal plating, which is known from a minimum depth of only 20 m compared with c. 175 m for Marginaster pectinatus Perrier, the only poraniid from the same area. Observation of this same character, agreeing conversely with the Poraniidae, in the genus Poraniopsis by Blake (pers. comm.) prompted him to suggest that it be removed from the Echinasteridae to this family. Perrier (1891: K106-107) failed to describe the arrangement of the actinal plates but Madsen (1956: 29) noted that their spines run parallel to the margin. Perrier thought Poraniopsis intermediate between Echinaster and Porania, emphasizing this by using echinaster as a specific name for the type species. Although he cited more characters in which Poraniopsis resembles Porania, more weight must have been given to those such as arm shape shared by Echinaster. Fisher (1911: 261) thought that resemblances to Porania are 'mostly superficial', holding to this view still in 1940 (pp. 154-155) when faced with an unusually well-armed Falkland Is specimen of Porania antarctica (Fig. IB). However, I find there are also important internal characters in which Poraniopsis agrees better with Porania than with Echinaster, comparing specimens from the vicinity of southern South America, as summarized in Table 1 . The abactinal plating is very similar, with the primary calycinal plates forming a pentaradiate pattern on the disc in both and irregular midradial (carinal) series forming part of an open reticulum; some nodal plates bear large spines and there are often superficial spinules in the skin. The latter are better developed in the truly antarctic subspecies P. antarctica glabra though minute ones c. 0-25 mm long are present Fig. 1 A. Poramopsis echinaster Perrier, BM reg. no. 1975.11.12.9, Chinquihue, S Chile, R 36mm; dry, partly denuded, showing spinules between the spines, x 2. B, Porania (Poranid) antarctica magellanica Studer, 1948.3.16.448. Discovery Investigations st. 80, Falkland Is, R 60 mm; wet, showing papulae between the spines, the spinules microscopic, x U. Fig. 2 A, Poraniopsis echinaster (as in 1A), partly denuded. x2. B, Porania (Poranid) pulvillus (O. F. Miiller), 1922.4.10.1, Lousy Bank, SW of Faeroe Is, R c. 36 mm; wet but contracted, the contours of the plates showing their limits, x 1J. C, Poraniella echinulata (Perrier), Pillsbury st. 853, Windward Is, R 10 mm; dry, partly denuded. x3. 24 A. M. CLARK Table 1 Comparison of Poraniopsis with Porania (especially P. antartica) and Echinaster. Agreement with Porania in capitals. Porania Poraniopsis Echinaster 1 r a a 2 C C I 3 s S N 4 d u u 5 a r r 6 M M L 7 D D S 4. Interradial arcs: a angular r rounded Primary calycinal plates: C conspicuous when denuded, linked to form a pentaradiate pattern I inconspicuous Skin: S usually containing a fine superficial secondary armament of small scattered spinules indepen- dent of the underlying plates N nude, armament limited to spines mounted on the plates Superomarginal plates: u relatively unspecialized, similar to the abactinal plates though corresponding in number to the inferomarginals; usually armed with one or more spines d distinct from the abactinals; spineless 5. Profile of ambitus (widest part of body): r rounded, curving into the upper and lower sides; inferomarginals inset somewhat on the ventral side, their spines not forming a continuous fringe a angular, the prominent ventrolateral angle emphasized by a prominent fringe of spines 6. Alignment of actinal plate series and any coarse armament: M in arcs across the interradii parallel to the mar- gin, the admarginal series the longest L in longitudinal lines along each ray parallel to the furrow, the adradial series the longest 7. Adambulacral plate joint faces: D with a deep restricted interadambulacral muscle depression towards the furrow face S with a shallow extensive muscle depression. Characters 6 and 7 carry the greatest weight in my opinion. in the Falklands specimen. There is also frequent alternation of the plates of the two marginal series of both Poraniopsis and Porania and the adambulacral spines are very few, thickly sheathed in skin and aligned at right angles to the furrow, besides the most obvious resem- blances of the thick opaque skin and the actinal plate arrangement. Sectioning of an arm shows that the proximal face of the adambulacral plates in Poraniopsis has a similarly deep interadambulacral muscle depression towards the furrow side to that found in the poraniids examined, quite different from the much wider and more shallow depression in Echinaster (see Blake, 1981, fig. 2, Chondraster and Echinaster, also Figs 7, 8 here). The main differ- ences in Poraniopsis consist of the better-defined rays with an angular rather than curved- interradial arc, the resemblance in shape and armament of the superomarginal plates to the primary (nodal) abactinals and the absence of a distinct ventrolateral angle, the infero- marginals having no horizontal abradial prolongation being instead slightly inset ventrally with the spines of consecutive plates quite discrete, not forming a continuous horizontal fringe. Although the diagnosis of the Poraniidae needs to be somewhat modified to accom- modate it, the balance of evidence, I believe strongly supports the inclusion of Poraniopsis. Madsen (pers. comm.) tells me that Mortensen placed Poraniopsis in the Asteropidae (then including Poraniidae) in the MS catalogue of asteroids in the Zoological Museum, Copenhagen, giving a clue to this disposition by placing Poraniopsis after Chondraster elattosis, well separated from the Echinasteridae in his table of south african echinoderms (1933: 225). Leipoldt (1895) also concluded that Poraniopsis belongs in the Poraniidae but this has generally been overlooked. ASTEROIDEA 25 Ten other nominal genera of poraniids are known from Atlantic waters. With the currently accepted name of the type species, these are: Porania Gray, 1840. P. pulvillus (O. F. Miiller, 1776) (as Asterias) Poraniomorpha Danielssen & Koren, 1881. P. hispida (M. Sars, 1872) (as Asterind) Tylaster Danielssen & Koren, 1881. T. willei Danielssen & Koren, 1881 Marginaster Perrier, 1881. M. pectinatus Perrier, 1881 Chondraster Verrill, 1895. C. grandis (Verrill, 1878) (as Porania) Culcitopsis Verrill, 1914. C borealis (Siissbach & Breckner, 191 1) (as Culcita) Poranisca Verrill, 1914. P. lepidus Verrill, 1914 Pseudoporania Dons, 1936. P. stormi Dons, 1936 Sphaeriaster Dons, 1939. S. berthae (Dons, 1938) (as Sphaeraster) Spoladaster Fisher, 1940. S. brachyactis (H. L. Clark, 1923) (as Cryaster). Two of these, Marginaster and Poranisca, are only known from small specimens, R<20 mm. Verrill (1914: 19) suggests that M. pectinatus is probably 'simply the young of Porania or some similar genus', while his own Poranisca was proposed 'as a matter of con- venience for another group of small young forms belonging to this family, until they can be connected with adults'. However, Downey (1973: 81) found some of the small Margin- asters from the West Indies to be sexually mature. It is not clear from Verrill's account just how he thought Poranisca lepidus differs from Marginaster. His photograph of the largest (syn) type (1914, pi. 1 , fig. 3a) is remarkably similar to the specimen of M pectinatus figured by Downey (1973, pi. 37, fig. A). Both have fairly numerous coarse abactinal spines. Verrill wrote: 'the type is from off the eastern coast of the United States, in 77 fathoms, no, 18,485, Nat. Mus.' A specimen with this catalogue number sent to me as a 'Type' of Marginaster austerus Verrill, 1899, was originally so identified by Verrill but subsequently he wrote 'For. lepidus V. Type' on the back of the earlier label. This label also bears in pencil an illegible Albatross station number beginning with 2 over which has been written 'near sta. 2265' the full station data for which are: 3707 '40 ' 'N, 7435 '40 ' 'W (off Chesapeake Bay) 70 fathoms. Since in 1899 (p. 222) Marginaster austerus was cited as from Blake and Albatross stations in the West Indies [my italics], in which area many hauls numbered at around 2350 were made, I think it very likely that the substituted number and hence the more northern type locality given for P. lepidus were misleading. It is significant that Verrill included no less than eight figures of Poranisca lepidus in his 'Starfishes of the West Indies' (1915) without having any mention of the species in his text, while the 'east of the U.S.' locality should have made it completely inappropriate. His plate, 4, fig. 3 shows this specimen, although it was not among the four illustrated in 1914 (pi. 1, fig. 3a-d) some of which have relatively broader inferomarginal plates, leaving little doubt that lepidus is a synonym of Marginaster pectinatus. Poranisca therefore becomes a synonym of Marginaster. A second Albatross specimen in the U.S.N.M. collection labelled as a 'type' of Marginaster austerus (cat. no. 10179 from st. 2333, 'off Havana, Cuba, 169 fathoms') proved to be a Poraniella echinulata (Perrier, 1881), the actinal plates being aligned parallel to the furrow and the five primary radial plates being conspicuously enlarged and convex. Little, if any- thing of Verrill's 1899 description of austerus could have been based on this specimen. The only other extant 'type' of M austerus is in the Peabody Museum, Yale (no. 9858) labelled by Verrill 'sta. unknown. West Indies, coll. A.E.V. Two enlarged photos; also draw- ings'. This has R/r 16-17/10 mm (17/1 1 according to Verrill, 1915: 78) and is almost cer- tainly the specimen with an abbreviated arm shown in his pi. 3, fig. 1 , la, captioned as 'type'. Most of his 1899 description (p. 221) could have been based on it except for descriptions of the primary calycinal plates as distinctly enlarged and the proximal actinal plates as bear- ing rows of spinules both contradicted in his 1914 and 1915 remarks, the latter specifically referring to the type. Accordingly, this specimen is the most appropriate one for selection as lectotype. Superficially it looks rather different from Marginaster pectinatus (compare Figs Fig. 3 A, B, Marginaster pectinatus Perrier, Pillsbury st. 876, Windward Is, R 1 5 mm; dry, partly denuded. C, Poraniella echinulata (as in 2C), dorsal view. D, E, Marginaster austerus Verrill, P. M. Yale no. 9858, lectotype, 'West Indies', R 16-17 mm; dry. AIIx3. ASTEROIDEA 27 2C, 3C and 3A, B) notably in the more evenly convex upper side after drying all the dried pectinatus seen being almost flat level with the tops of the superomarginal plates; also the number of marginals is greater, 8-10 rather than 7 or 8 in pectinatus of similar size and the inferomarginals project less, forming only an inconspicuous border in ventral view; lastly, the superomarginals in austerus are armed with spaced spines for their full height, not just at the upper end, whereas pectinatus usually has a bare belt above the inferomarginals, only occasionally a few longer superomarginal spines. The first of these differences may be attributable to an artefact of preservation but the others together could provide a significant difference. However, in general the remaining armament is similar and I suspect that austerus will prove to be a synonym of pectinatus when more material is available. It should be noted that Verrill's pi. 11, fig. 6a (1915) misrepresents the adradial actinal plates as being in line with the furrow; they are parallel to the margin as usual in poraniids. There is a further possibility that Marginaster itself could be a synonym of Porania, to which genus Verrill provisionally referred austerus in 1914 (p. 20). In 1895 (pp. 138-139) he wrote of P. insignis from east of the U.S.A. 'Young specimens- -have more or less numer- ous small, scattered simple spines, both on the dorsal and ventral plates; these plates are distinctly visible, beneath the cuticle, when dried, and the upper marginal plates are rela- tively larger than in the adult. The papulae are few and scattered. In this stage, it agrees in all respects with the genus Marginaster Perrier and Lasiaster Sladen, both of which are probably the young of Porania or Poraniomorpha '. Possibly Lasiaster was added here as an afterthought, since he used the singular 'genus'; it has since been synonymized with Poraniomorpha. A proper comparison of M. pectinatus with small Poranias from off the USA may shed more light on the relationship and the status of the name Marginaster. As for the even smaller (R max. c. 10 mm) geographically 'fringe' species (latitudinally). Marginaster capreensis (Gasco, 1876: 38) from the Mediterranean in 50-c. 600 metres this is very similar in abactinal and marginal armament to M. pectinatus but has more numerous actinal and adambulacral spines. In comparison, the N. european Porania pulvillus loses the few actinal spines found in juveniles more quickly than the american P. insignis. A fourth atlantic Marginaster is M. fimbriatus Sladen, 1889: 365-366, known only from the holotype, R 6 mm, from the Rockall Trough, W of Scotland, in 2487 metres. The name fimbriatus was synonymized with Marginaster capreensis by Ludwig (1897: 190), prompting Mortensen's inclusion of the latter in the british fauna (1927: 92). However, recent collecting in the Rockall Trough has produced several specimens from down to 2070-22 10m which are much more likely to be the same species although the smallest, R 22 mm, is much larger than Sladen's type. I believe that these are referable to the genus Chondraster and conspecific with Chondraster grandis (Verrill, 1878: 371-372), known for off Cape Cod to Cape May, U.S.A. in c. 400-1645 m. One of Farran's three specimens (from Helga st. SR 483) named by him Culcita borealis Sussbach & Breckner (1913: 15-16) also proved to be grandis besides several others from various sources extending to the Bay of Biscay at c. 44N, 04-5W. (Biogas VI st. CP 29). Arm sections and X-rays of some of them show a single horizontal row of slender tapering inferomarginal spines, as in Porania, numbering up to 4 on a plate, but these are completely enveloped by the very thick body wall, not individually sheathed; only by excessive shrinkage in preservation does their presence become evident externally. The proximal superomarginals are deeply inset, aligned vertical but somewhat obliquely, tall and flattened, exaggerated in form from those of Porania, while the inferomarginals are flattened horizontally and markedly elongated at right angles to the edge of the body, the spines usually present borne along their abradial ends (see Fig. 7D). The actinal plates are very elongated and overlap to form series linking the inferomarginals with the adambulacrals. A section of a large specimen, R c. 73 mm, shows only a few small, hollow, isolated abactinal plates. X-ray show the density of the other skeletal plates is also low. The adambulacral plates bear usually 2 individually-sheathed furrow spines and 2, sometimes 3, subambulacral spines within a single elongate sheath aligned almost parallel to the furrow, contrasting with the single transverse row in Porania. The smallest specimen, R 22 mm, from the southern Bay of Biscay, is dried, which helps to show a better developed skeleton approximating to that Fig. 4 A, B. Chondrasler grandis (Verrill), 1981.7.20.1, Rockall Trough, R 73mm; partial dorsal and ventral views, x 14. Fig. 6 X-rays of Chondraster grandis (Verrill): A, No details, off Cape Cod, specimen probably dried and shrunken, R c. 15 mm. B, (as in 4). x 1$. ASTEROIDEA 31 Fig. 7 Partial cross section near base of ray viewed from proximal side of: a, Poraniopsis echin- aster Perrier, 79.8.19.6, Magellan Strait, R c. 37mm; b, Porania (Porania) pulvillus (O. F. Miiller), 1950.1 1.3.1, Porcupine Bank, W of Ireland, R 55 mm, the cross-hatched area of the second superomarginal hypothetical, the plate cut in sectioning; c, P. pulvillus, 90.5.7.511, Porcupine st. 8, W of Ireland, R 14 mm; d, Chondraster grandis (Verrill), 1981.7.20.1, Cirolana st. 22, E side of Rockall Trough, R c. 73 mm; e, Porania (Pseudoporanid) stormi (Dons), 1 920. 1 2.28.3 1 , Lousy Bank, SW of Faeroe Is, R 40 mm, the median part of an adjacent complete inferomarginal plate shown by discontinuous lines. i = inferomarginal, s = superomarginal. The scale measures 5 mm. 32 A. M. CLARK Fig. 8 Partial cross sections near base of ray viewed from proximal side of: a, Poraniomorpha (Culcitopsis) borealis (Siissbach & Breckner), IOS st. 50702, Porcupine Seabight, R 19 mm; b, P. (Poraniomorpha) hispida (M. Sars), 98.5.3.223, Trondheim fjord, R 26-5 mm (inferomarginal armament dubbed from another specimen); c, P. hispida rosea Danielssen & Keren, SMBA st. AT 230, Rockall Trough, R 33 mm. Plates well out of the plane of the section are shown by discontinuous lines; i = inferomarginal, s = superomarginal. The scale measures 5 mm. of Porania pulvillus with the primary radial and interradial abactinal plates distinct on the disc and irregular carinal series linked to some of the superomarginals by transverse chains of dorsolateral plates; however, the proximal marginals are of more exaggerated form than in Porania. There are 2-4 inferomarginal spines on each plate and 1, sometimes 2, spines on many plates of the adjacent actinal series, as in some adults of the american Porania insignis and the arctic Tylaster willei. The larger Chondrasters all lack actinal spines and show varying degrees of skeletal reduction. The extent of the papulae is also very variable, from the two narrow bands along each ray shown in Verrill's figure (1885, fig. 44a), to a wide coverage of the upper side except for small midradial and interradial bands; some papulae may even occur between successive superomarginals. Although these specimens are clearly conspecific with Chondraster grandis from the NW Atlantic, they might be subspecifically distinct. An X-ray of an american specimen, R c. 75 mm (Fig. 6A), shows discontinuous series of inferomarginal spines, with 1 or 2 on most interradial and some distal plates, not in between. The inferomarginals appear hollow almost to the abradial extremity in contrast to those of the NE Atlantic specimens but vestiges of actinal and possibly some abactinal plates are similarly distinguishable. Another specimen, from Lydonia Canyon, SE of Cape Cod, R c. 55 mm, shows up to 3 spines on most infero- marginals but no trace of any abactinal or actinal plates; the marginals themselves are ill- defined, whereas a larger similarly dried NE Atlantic individual (from Lousy Bank, SW of the Faeroes), as well as the large wet Rockall Trough specimen, show quite distinct outlines of many actinal plates at least, indicating that the dried and contracted condition is not responsible for the skeletal loss in the american specimen. One of Verrill's two syntypes of C. grandis has been examined, the second is not to be found in the Peabody Museum, Yale. It is considerably shrunken and flattened with all the rays curled upwards and the distal part of one broken off. Although now in alcohol it may have dried up at some time judging from the extreme flattening and shrinkage of the body wall. Mean R is estimated at c. 95 mm; in life it was probably 100+ mm; r is c. 50mm. Superficial spicules all over the upper side give a 'furlike' appearance; on the lower side they are more spaced out, especially proximally. The broken edge of the detached ray shows no sign of any abactinal plates, even in this distal area where resorption is likely to be mini- mized. However, the actinal plates are still fairly well developed, though hollow, and there are 1-3 spines on the abradial ends of four inferomarginal plates from which the tissue has been pared. Indeed, contours corresponding to actinal plates are evident all over the ventral ASTEROIDEA 33 interradii, though it does not follow that the plates remain well developed since similar con- tours may show in poorly preserved specimens of other skeletally deficient poraniids even though X-rays show only vestiges of actinal plates. The papulae are restricted to two narrow bands along each ray, as in Verrill's fig. 44a, 1 885, and the same is true of four other american specimens, three of them from Lydonia Canyon, which is on the south side of George's Bank not far WSW from the type locality. R is c. 55-105 mm, probably at least 60-120 mm in life since they are dried and very shrunken so that the cluster of spinelets around the anus stands out. The number of subambulacral spines ranges from 2 or 3 in the smallest to usually 4 in the largest and the number of oral furrow spines is 6-8 with a single suboral, except in the smallest specimen which has none. Verrill initially (1895: 138) treated Chondraster as a subgenus of Porania but in 1914 (p. 21) evidently accorded it generic rank, being followed in this by H. L. Clark (1923: 274-275) when describing a new species from South Africa. However, in 1959 (p. 160) Madsen thought subgeneric rank to be more appropriate when he described another poraniid, from E Greenland, as Porania (Chondraster) hermanni. Since then (pers. comm.) he has come to believe that hermanni is a Porania sensu stricto and Chondraster generically distinct mainly on account of the longitudinal arrangement of the adambulacral armament in C. grandis, whereas Porania has these spines in a transverse row. A final atlantic nominal species of Marginaster should be mentioned, namely M. pentago- nus Perrier, 1882: 51) (also 1894: 165-167, pi. 11, fig. 4), the holotype and only recorded specimen of which had R 3 mm, the body form retaining post-larval flattened shape with the inferomarginal plates (numbering 6 on each side in this specimen) alone forming the periphery, the superomarginals being inset on the upper surface and resembling the some- what imbricating polygonal abactinal plates, all bearing a scattering of spinelets. The infero- marginals each bear a comb of 6-8 spinelets along the free edge but apparently inclined downwards. On the under side most actinal plates have one or a few small spinelets and the adambulacrals bear a furrow spine and two or three subambulacral spines in a transverse series. Mortensen (1927: 94) and Tortonese (1965: 167) suggest that pentagonus could be conspecific with the mediterranean M. capreensis but that species has fewer and coarser abactinal spinelets and inferomarginal spines, judging from Ludwig's illustrations (1897, pi. 7, figs 2 1-23). The type locality of M. pentagonus is NW of Finisterre, Spain (c. 44N, 10-5W) in 400 metres. The closest geographical record for a poraniid is that of Gallo (1937: 1664) for three specimens from Santander, N Spain, also in 400 m, resembling Culcitopsis borealis (Siissbach & Breckner, 1911: 217-218) although he named them Poraniomorpha hispida (M. Sars, 1872: 26), following Mortensen's synonymy of borealis with hispida in 1912 (p. 258) and 1927 (p. 93). The small and relatively numerous inferomarginal spinelets support inclusion of pentagonus in Poraniomorpha despite the single furrow spines which are probably corre- lated with the small size. However, the status of Culcitopsis needs reassessing since Farran (1913: 15),Koehler(1924: 160-1 61) and Cherbonnier & Sibuet(1973: 1348) have recorded as C. borealis specimens from the Porcupine Seabight (SW of Ireland) and from the NE Bay of Biscay. Mortensen, and also Grieg (1927: 131) had discounted the swollen form and thickened body wall with reduced skeleton of C. borealis as insufficient to warrant more than an infra- specific difference from Poraniomorpha hispida, designating such specimens as forma borealis. Madsen too (pers. comm.) strongly supports such a low rank, believing that borealis is an ecophenotypic form. Certainly most poraniids show some progressive resorption of the skeleton during growth so that even in apparently well-calcified large specimens of Porania and Poraniomorpha the marginals and other plates may be hollow, as evidenced by sectioning or by X-rays a useful technique for study of this family of thick-skinned asteroids. In addition to the above mentioned authors, others have also commented on the consider- able variation in several directions of Poraniomorpha hispida, notably Djakonov (1946: 163-169, at length, in russian), who compared it with the exclusively arctic P. tumida 34 A. M. CLARK (Stuxberg, 1878: 31), finding intermediate specimens where the ranges of the two overlap (presumably in N Norway and the Barents Sea), mentioning this briefly in his book on russian asteroids (1950: 59, translation 1968: 50). Unfortunately it is not possible to ascertain the adult form of Sars' material since his holotype (from the Lofoten Is, N Norway, 365-550 m) has R only 6 mm. Although it does have a near pentagonal form, R/r 1-2/1 (see Sars, 1877, pi. 8, figs 24-26), this could be true of a more stellate adult when young. However, Grieg (1927: 129-133) makes several references to the 'typical' form, which by implication is a shorter-rayed one since he also refers separately to forma rosea, Danielssen & Keren's holo- type of which had R/r 1 -67/1 and appears relatively stellate in their figures. Djakonov (1950) also described P. hispida as having a massive body, broad disc and broad, very short, rays. In the absence of any evidence to the contrary, this is the form which can be attributed to 'typical' hispida. All nine norwegian specimens in the British Museum collections with well developed skeletons (from Hardanger and Trondheim fjords, from SW of Bergen and off the North Cape) consistently have a pentagonal form, R/r 1-3-1-5/1 (R 7-45 mm). Ostergren (1904: 615) recognized rosea as a distinct variety of hispida, followed by Grieg (1907: 42) who noted that specimens from Bergen and Trondheim fjords as well as from Bohuslan in the vicinity of Oslo fjord (i.e. close to shore) are short-rayed whereas those from the deep area of the Skagerrak (500-600 metres) have relatively long rays. The latter form with R/r c. 2/1 and triangular rays forming angular interradial arcs was illustrated by Mortensen (1927, fig. 53, taken from his earlier 'Danmarks fauna') but does not appear to be found on the continental shelf in british waters, only from the bathyal at 900-1400 metres to the NW and W of the British Isles, from which c. 20 specimens are consistently stellate. These include two small syntypes ofLasiaster villosus Sladen, 1889: 372 (synonymized with Pora- niomorpha hispida by Grieg and others), the specimen from Helga st. SR 506 (Fig. 1 1 B, C) named P. villosa by Farran (1913: 17) and others more recently collected in the Rockall Trough and Porcupine Seabight. The only exception is the holotype of Rhegaster murrayi Sladen, 1889: 368-371 (Fig. 11 D, E) (another synonym of P. hispida) from the Wyville Thomson Ridge in 5 10-790 metres, which has a near pentagonal form, R/r 1 -3/1 but R only c. 14mm. The type locality of Poraniomorpha rosea Danielssen & Koren, 1881: 189-192; also 1884: 67-70, the oldest species-group name for stellate european specimens, is NW of Bergen (6141'N, 03 19 'E) in 402 metres, that is in the southern arm of the Norwegian Sea which leads to the Skagerrak. On the basis of this evidence, it is possible that short and long rayed specimens are isolated in different water masses. However, Madsen (pers. comm.) finds considerable overlap in norwegian waters. Nevertheless I believe that rosea can be accorded at least subspecific rank. It should be noted that rosea is antedated by two other names long synonymized with P. hispida, namely Asterina borealis Verrill, 1878: 213-214 and Porania spinulosa Verrill, 1880a: 202-203 (Fig. 11F), based on moderately long-armed type material from american waters N and E of Cape Cod. R/r of the respective types is 12/7 = 1-7/1 (implying a higher value when fully-grown) and 40/23 = 1-75/1. Paucity of american material for comparison prevents a proper assessment of the affinites of specimens from east and west and I can only note that the american ones appear to have the interradial arcs more curved and the tips of the rays blunter than is usual in european ones. In 1895 (p. 139) Verrill noted that spinulosa was taken 'mostly in the warm area' and borealis in the 'cold area' but in 1880 (b: 401) he had recorded both from USFC stations 869 and 879 and in 1914 (p. 18) he remarked that his 1895 notes (p. 139) on a relatively large specimen (R/r 35/23 mm) from the Fishing Banks (c. 45-5N, 57W, in 170 fathoms) refer not to borealis but to spinulosa. With such confusion and overlap it is impossible to assess if two infraspecific taxa exist in american waters until more material is available. With regard to the decalcified adult specimens such as have been referred to Culcitopsis borealis (Sussbach & Breckner), the range of these appears to parallel to a great extent that of P. hispida rosea. Twelve samples range from the Porcupine Seabight W of southern Ireland N and E to the Faeroe Channel, Shetlands and N Norway (Lofoten Is) in depths down to c. 1000 metres though with a minimum of only 1 10 metres. These show a near- Fig. 9 A, B, Poraniomorpha (Poraniomorphd) hispida (M. Sars), 9 1 .4. 1 5. 1 , Trondheim fjord, R 32 mm, dorsal and side views, partly denuded. C-F, P. (Culcitopsis) borealis (Siissbach & Breckner): C, (as in 8a); D, 1956.5.25.5, E of Shetlands, R 25 mm, both dorsal views; E, F, 1974.1.4.2, E of Wyville Thompson Ridge, R c. 44mm, side views, E wet, external; F dry, internal. Others all wet, x 1^. Fig. 10 A, Poraniomorpha (Poraniomorphd) hispida (M. Sars) (as in 9A, B), ventral view. B-F, P. (Culcitopsis) borealis (Siissbach & Breckner): B, C, (as in 8a) ventral and side views; D, E, (as in 9D) ventral and side views. All wet, x 1^. Fig. 11 A, Poraniomorpha (Culcitopsis) borealis (Siissbach & Breckner), National Museum of Ireland no. 102.1913, Helga st. SR 223, R c. 40mm, ventral view. B,C, P. (Poraniomorphd) hispida rosea Danielssen & Koren, Nat. Mus. Ireland 403.1913, Helga st. SR 506, R 28 mm, ventral and dorsal views. D-F, P. hispida hispida (?): D, E, holotype of Rhegaster murrayi Sladen, 90.5.7.545, Triton st. 5, Wyville Thomson Ridge, R c. 14 mm, dorsal and ventral views; F, presumed holotype of Porania spinulosa Verrill, Peabody Museum, Yale no. 9867, off Cape Cod Light, R 40 mm. A, wet; others dry; D, Ex 2; others x 1^. Fig. 12 X-rays of Poraniomorpha (Culcitopsis) borealis (Siissbach & Breckner): A (as in 8a); B (as in 9D); C, IOS st. 50601, Porcupine Seabight, R 35 mm; D, 1965.5.24.4, Lofoten Is, R. c 72mm.xli. Fig. 13 X-rays of Poraniomorpha (Culcitopsis) borealis (Siissbach & Breckner): A, IOS st. 9752, Porcupine Seabight, R 40mm; B, 1966.1.13.45, SE of Wyville Thomson Ridge, R. c. 47 mm.x U. 40 A. M. CLARK pentagonal outline, R/r < 1-5/1, are more or less high and cushionlike with the body wall thickened and agree with Siissbach & Breckner's holotype of C. borealis, taken NE of the Shetlands in 1 34-2 1 5 metres. The papulae are in close clusters, the upper surface otherwise appearing fairly smooth superficially but studded with numerous embedded fine spinules visible under magnification, the ventral surface somewhat pustular and the adambulacral spines heavily sheathed. Most of these characters are at variance with 'typical' Poraniomor- pha hispida where the body is flattened though thick and the superficial armament is distinct and almost continuous, covered over with only thin skin. X-rays of six of the borealis-\ike specimens ranging in size from R 19-72 mm are shown in Figs 12 and 13. As would be expected, the maximum calcification of the skeleton appears in the smallest where the interbrachial septa are partly calcified. However, even here many of the marginals and actinals (or abactinals) showing in the interradii have a fairly large cen- tral cavity and the body shape (Fig. IOC) is markedly inflated, much as in Greig's specimen of similar size (1927: 132-133, figs 3-5) from Michael Sars st. 32 (W of Kristiansund, Norway, 400 metres, upon which (rather than his larger ones) I suspect Grieg based his obser- vation that 'the skeleton of the disc is well developed and agrees completely with that of Poraniomorpha hispida ' though he notes that the surface armament is hidden in the thick skin. Although the rate of calcite resorption varies to some extent as shown in the X-rays (compare Figs 12C & 13 A, B), at R>40 mm only vestigial outlines of most plates are evi- dent, at best. This compares with a flattened Trondheim specimen of P. hispida (Figs 9A, B, 10A, 14) with R c. 32 mm in which the abactinal and actinal plates and interbrachial septa appear well calcified and the marginals solid and blocklike. Even in a specimen of hispida with R > 50 mm, from the Skagerrak in 660 metres, X-ray kindly sent by Dr Madsen, the skeletal development still appears much the same except that the interradial plates of one of the marginal series are reduced and hollowed to a similar extent as the corresponding plates of the borealis with R only 19 mm (Fig. 12 A). Clearly there should be considerable similarity in the skeletons of juvenile borealis and hispida, the main skeletal differences Fig. 14 X-ray of Poraniomorpha (Poraniomorpha) hispida (M. Sars) (as in 9A, B). x \{. ASTEROIDEA 41 being in the timing and extent of resorption. However, the resultant morphological difference in well-grown specimens is so marked (compare also the side views shown in Fig. 9B, E) that I find it impossible to believe there is insufficient genetic difference to justify a specific distinction for borealis, as well as a subgeneric one for Culcitopsis within the genus Poranio- morpha. My conclusion that borealis is more than just a form of hispida is supported by a notable enlargement and distal inclination of a single pair of suboral spines on each jaw of most specimens of borealis (see Fig. 11 A), suggesting a modification in feeding habits (perhaps approaching that ofOdontaster which has similar projecting but hyaline- tipped oral spines used for rasping on sponges). A similar modification, but of the apical pair of oral spines, is shared by Poraniomorpha bidens Mortensen, 1932: 9-12 from Greenland (recently taken also in the cold area of the Faeroe Channel NE of the Wyville Thomson Ridge). P. bidens has a furlike coating of very fine superficial spinules of papillae clearly visible through the thin skin, as in P. hispida, but a general body form with tapering pointed rays, as in the other arctic species, P. tumida (Stuxberg) where the superficial armament is much coarser, almost granuliform. Additionally, the colour in life of borealis appears to be generally much paler than that of hispida, the darkest cited being pale orange above; it is more often yellow or pale yellow, white below, whereas hispida is said to be: rose red above, orange below; dark violet-red above with white papulae, reddish-white below, or pale reddish-yellow all over. As mentioned previously (p. 34), intermediates exist in northern Norway between the polymorphic hispida and tumida where the two taxa overlap. Clearly the taxonomy of the entire genus Poraniomorpha needs to be reviewed, not just the Atlantic members within the scope of the present study. It should be noted that in addition to the natural differences correlated with the skeletal development, decalcified specimens can be drastically modified in appearance by changes in preservation. For instance, the large specimen, R 72 mm (Fig. 12D) from the Lofoten Is in the British Museum collection, thought to be P. (C.) borealis is badly flattened with the upper side crinkled and the whole body wall excessively contracted so that the superficial spinules are brought together in an almost continuous coating, as is usual in Poraniomorpha hispida, the identification it had prior to being X-rayed. The extent of shrinkage possible in these poraniids is shown by the holotype of Sphaeriaster berthae (Dons, 1938: 163-164), from N of the Lofoten Is, which had R 90-1 15 mm in life but was only 77-80 mm after preservation in spirit. Change in body shape may also be drastic, as shown by Spoladaster veneris (Perrier), from St. Paul's I, southern Indian Ocean where live specimens may be markedly stellate but preserved ones become pentagonal see A.M.C., 1976, pi. 6 and pi. 3, fig. 2. Madsen and I have no doubt that S. berthae is synonymous with borealis so that Sphaeriaster itself is a synonym of Poraniomorpha. Dons's second nominal species, S. bjoerlykkei, (1938: 165-168) type locality N of the Shetlands in 300-350 metres, R/r 87/47 = 1-7/1 so fairly stellate, shows a high density of superficial spinules as in our Lofoten Is specimen just mentioned. A new X-ray sent by Madsen shows very faint outlines of plates, much as in large borealis, but he thinks that it is more likely to be decalcified P. tumida', Dons described multiple furrow and subambulacral spines, more than usual in borealis. Another taxon with a very reduced skeleton in larger specimens is Spoladaster Fisher. In 1976 (in Clark & Courtman-Stock: 73) I suggested that Tylaster meridionalis Mortensen, 1933: 249-250, from the same area W of South Africa, based on a specimen with R only 28 mm, is probably a synonym of S. brachyactis (H. L. Clark, 1923: 293-294), of which R is 40-80 mm in the few specimens recorded. Studies now on the growth changes and vari- ation of P. (C.) borealis confirm me in this view. It is noteworthy that no better-calcified Poraniomorphas have been collected in south african waters. S. brachyactis shows some deve- lopment of macroscopic inferomarginal and actinal spines, such as are found in greater numbers in Tylaster willei Danielssen & Koren, 1881: 186, from the northern Norwegian Sea (see Danielssen & Koren, 1884: 64-67). This species too has the underlying skeleton very reduced. These taxa illustrate the ability of poraniids to utilize coarse armament even though this is, at best, articulated only to rudiments of skeletal plates in the thickened body 42 A. M. CLARK wall. Tylaster and the other arctic taxa mentioned come within the range of the series 'Marine Invertebrates of Scandinavia', the asteroid part of which is in preparation by Madsen. Hopefully he will be able to clarify the relationships of these if more material is available. There is yet one more conspicuous example of skeletal reduction in poraniids, exemplified by Pseudoporania Dons. Again I am indebted to Madsen for an X-ray, of the holotype of P. stormi Dons, 1936: 1 7-20, from Trondheim fjord in 300 metres, R 83-96 mm. This shows that the actinal and marginal plates have contracted down into very small, widely separated rods or partially hollow nodules of calcite, the more interradial inferomarginals being appar- ently reduced to a rudiment of their abradial, possibly also adradial ends. This is just the progression I would expect from the condition found in six much smaller specimens, R 19^40 mm, one from the Porcupine Seabight, the others from around the Wyville Thomson Ridge, S of the Faeroes, in depths of 360 (?183)-770 (7927) metres. These too have a smooth surface above and below, apart from well-marked actinal grooving. Sectioning shows the lateral body wall to be extremely thick (Fig. 5B) and X-rays show no signs of inferomarginal spines, even on the distal plates in the smallest (Fig. 1 6A, B), the ambitus being rounded. The body form is flattened and pentagonal whereas Don's specimen has short tapering rays. The papulae are relatively sparse and scattered. The adambulacral plates are armed with single furrow and subambulacral spines (the sheath of the latter continuous with the thick- ened ventral body wall), which appeared to provide a distinction from stormi but Madsen informs me that it too has single spines, Dons' description of 2 + 2 being incorrect. The smallest specimen has the marginals blocklike except for the interradial inferomarginals which project abradially. The sections and X-rays show progressive attenuation of the plates with division of the interradial inferomarginals into two small end pieces, ad- and abradial, by loss of the middle part. This is very different from the resorption shown by Poranio- morpha (C.) borealis, which is almost entirely from the inside, the plates being reduced to hollow, usually rectangular or ovate, shells. The complete absence of any superficial spinules and the small number of adambulacral spines, with only single furrow spines, agrees more closely with Porania than any other genus of the family, though the great thickening of the body wall and the absence of a distinct ventrolateral angle emphasized by a horizontal fringe of individually sheathed inferomarginal spines results in a very different appearance. In 1983 (in Gage et al.: 281) I noted that a specimen of Porania pulvillus (O. F. Miiller, 1776: 234) from the Rockall Bank in 148 metres with R 55 mm has the inferomarginal spines drastically reduced from the usual 3-5 on each plate to only 1 or 2 on some of the more interradial plates and none on the distal plates. Nevertheless, the remaining spines are indi- vidually sheathed and projecting from the ambitus and the usual ventrolateral angle is still distinct, the body wall not being markedly thickened. An X-ray of this specimen (Fig. 18B) shows that a few of the interradial inferomarginal plates are slightly compressed, recalling those of the smallest specimen of stormi (Fig. 16A), though the modification is much less. Madsen (pers. comm.) has found occasional specimens of P. pulvillus from Norway with the inferomarginal spines more or less reduced but the skeleton otherwise well developed. Addi- tionally he has sent X-rays of two other specimens, R probably 25-30 mm, with the inter- radial marginals much reduced, some divided into two parts and the body wall obviously much thickened. Although he finds these akin to Pseudoporania stormi, he considers this to be a synonym of Porania pulvillus. One (from S of Iceland, Thor st. 166) appears to have nearly all the marginals narrowed down and completely lacking spines, much as in the Porcupine Seabight specimen (Fig. 16B) but the other (Troms0 Museum, probably from N Norway) has about 3 inferomarginal plates each side of the very reduced interradial plates in each interbrachial arc with a rhombic abradial part bearing 1, rarely 2, large spatulate spines. In face of such intermediate specimens, there can be little doubt that Pseudoporania should be referred to the synonymy of Porania, in a comparable way to Culcitopsis and Poraniomorpha. However, the general form of adults of the several Porania species, with a distinct ventrolateral angle and the body wall no more than moderately thickened is so Fig. 15 Porania (Pseudoporanid) stormi (Dons): A, B, (as in 5B), dorsal and ventral views; C D. Royal Scottish Museum, Walter Herwig st. 848, S of Faeroe Is, R 19 mm, dorsal and ventral views; E, IOS st. 50601, Porcupine Seabight, R 35 mm. All wet,x 1^. 44 A. M. CLARK Fig. 16 X-rays of Porania (Pseudoporanid) stormi (Dons): A (as in 1 5B, C); B (as in 1 5E). x 1^. consistent that here again I believe a subgeneric distinction is justified, in spite of Madsen's opinion to the contrary. It seems likely that P. stormi is zoogeographically isolated from pulvillus. The present records indicate that pulvillus alone is found on the shelf around the British Isles and in southern Norway N to about Trondheim fjord, to a minimum depth of Fig. 17 Porania (Porania) pulvillus (O. F. Muller): A (as in 5C); B, C, 1950.1 1.3. 1, Porcupine Bank, R 55 mm, dorsal and part ventral views. Both wet,x \\. Fig. 18 X-rays of Porania (Porania) pulvillus (O. F. Miiller): A (as in 5C); B, 1981.3.24.28, Rockall Bank, R 55 mm (the inferomarginal spines only show in one interradius though in fact present in the others; a section of one arm removed), x 1^. ASTEROIDEA 47 5 metres (a new record from Lunna, Shetland Is where it was collected by a diver) and a maximum of c. 250 metres, whereas P. stormi is an upper bathyal species limited to more remote areas, from S of Iceland to the continental slope W of the British Isles and possibly from N Norway. However, there is a much closer morphological resemblance between Porania pulvillus and the american P. insignis Verrill, 1895: 138-139. The former is consistently relatively thin-walled with a well-marked ventrolateral angle. Although the available material suggests that the abactinal skeleton may be more open in the american taxon, the main difference is that some adults retain a few actinal spines whereas these are almost invariably lost at an early stage in P. pulvillus. Madsen (pers. comm.) has independently reached the same conclusion. To provide a summary of the main diagnostic characters used in identification of poraniids, a tabular key to the genera and subgenera now accepted is given here (Table 2). Table 2 Tabular key to the genera of Poraniidae. Alternate columns in lower case. Poraniopsis W s(i) C-O r SD q-j- T Porania (Porania) W(R) n,s(i) O a SC q + / T Porania (Pseudoporanid) R n o r L q- T Tylaster R i 7 r S*(D) q+ T Spoladaster R i 0(C) r SD q,p( + ) T Chondraster R n o a(r) H q-[+] M Poraniomorpha (Culcitopsis) R i c r L[M] P- M(T) Poraniomorpha (Poraniomorpha) W f C(S) r M s + /- M(T) Marginaster [W] [s] [S] [a] [SC] [q-] U] Note: Square brackets indicate occurrence in small specimens, as throughout in Marginaster; round brackets show the condition in occasional specimens or a modified form. *In Tylaster willei the inferomarginal spines are evidently in triangular groups of three, not a horizontal line. 1 . Abactinal skeleton: H-hidden in live or well-preserved specimens, the W-well developed few large spines wholly within the much thick- R-more or less reduced by resorption, especially in ened body wall large specimens, R > 50 mm L-lacking altogether 2. Superficial dorsal body wall: M-of multiple spinelets clustered along the ventro- f-with very fine continuous or clustered spinules, lateral convexity tubercles or papillae, not necessarily articulated S-of up to 5 large spines in a horizontal row, at to the underlying plates least their tips projecting, forming either a con- i-with fine isolated spinules, not articulated to the tinuous fringe (C) or a discontinuous grouped plates series (D) n-naked and smooth, sometimes with surface spic- 6. Appearance of actinal areas (apart from the ciliated ules so dense as to show a pale colour when dried grooves between the furrows and margins): s-with spaced relatively large spines mounted on p-pustular the larger plates or vestiges of plates q-quite smooth (apart from any macroscopic 3. Papulae: armament) C-clustered s-with fine superficial spinules, usually slightly O-in open groups, short arcs or evenly spaced over spaced wide areas +/ with or without enlarged spinelets or spines S-single in series parallel to the inferomarginals 4. Shape of margin: 7. Adambulacral armament: a-more or less distinctly angular ventrolaterally, T-arranged normally in one series transverse to the corresponding to the horizontally projecting furrow, usually 2 or 3 spines inferomarginals M-with multiple furrow spines on most plates, r-rounded, the inferomarginals hardly, if at all, subambulacral spines variously arranged, paired, projecting or else both series of plates reduced in an oblique but nearly longitudinal series with- 5. Inferomarginal armament: in a common sheath, or transversely 48 A. M. CLARK Nomenclature The classification of the Poraniidae has been complicated not only by the thick skin obscuring the usual diagnostic characters afforded by the skeleton but also by failure to allow for ontogenetic changes and an unwise propensity of certain early workers to give new names to juvenile or small specimens. Consequently, the names of certain species-group taxa are threatened by the possibility that they will be proved to be synonymous or homonymous with prior nominal species, as follows: Poraniomorpha (Culcitopsis) borealis (Siissbach & Breckner, 191 1) is threatened by two possibilities, firstly: Asterina borealis Verrill, 1878 (holotype extant in the Peabody Museum, Yale, R 12mm), long synonymized with P. hispida, may prove to be consubspecific with P. (Poraniomorpha) hispida rosea Danielssen & Koren, 1881, which it antedates. In this eventuality and if the subspecies now proposed is accepted, then borealis Verrill would be a senior species-group homonym within the genus Poraniomorpha. Secondly: Marginaster pentagonus Perrier, 1882 (holotype extant in the Paris Museum, R only 3 mm) may prove to be a senior synonym. The name pentagonus has only been mentioned as a possible synonym since Perrier, 1 894. Porania pulvillus insignis Verrill, 1895 is threatened by: Asterina pygmaea Verrill, 1878 (holotype extant in the Peabody Museum, R only 5 mm), which may prove to be a senior synonym. The name pygmaea has been unused since referred to Poranisca by Verrill, 1914. Porania antarctica Smith, 1876 is threatened by: Astrogonium fonki Philippi, 1858, which Madsen (1956) has little doubt was based on specimens con- specific with P. antarctica magellanica Studer, 1876 but which he assumed are no longer extant in any Chilean collection since they were not mentioned in Meissner's note on Philippi's asteroids of 1898. The name fonki has been unused since 1858 but P. antarctica is widely utilized. Summary of taxonomic confirmations or changes Poraniella Verrill, 1914, referred to the family Asteropseidae from Poraniidae. Poraniopsis Perrier, 1891, referred to the family Poraniidae from Echinasteridae. Poranisca Verrill, 1914, with type species P. lepidus Verrill, 1914, synonyms of Marginaster Perrier, 1881 and M. pectinatus Perrier, 1881. Chondraster Verrill, 1895, confirmed as of generic rank, distinct from Porania Gray, 1840. Poraniomorpha rosea Danielssen & Koren, 188 1 , treated as a subspecies rather than a form or variety of P. hispida (M. Sars, 1872). Culcitopsis Verrill, 1914, type species Culcita borealis Siissbach & Breckner, 191 1, treated as subgenus of Poraniomorpha Danielssen & Koren, 1881. Culcitopsis borealis (Siissbach & Breckner), treated as a separate species rather than a form of Poranio- morpha hispida (M. Sars). Sphaeriaster Dons, 1939, type species Sphaeraster berthae Dons, 1938, synonyms of Poraniomorpha (Culcitopsis) Verrill and P. (C.) borealis (Siissbach & Breckner). Tylaster meridionalis Mortensen, 1933, confirmed as a synonym of Spoladaster brachyactis (H. L. Clark, 1923). Pseudoporania Dons, 1936, type species P. stormi Dons, 1936, a subgenus of Porania Gray. Porania insignis Verrill, 1895, reduced to a subspecies of P. pulvillus (O. F. Miiller). Taxa the affinities of which need further investigation: Asterina borealis Verrill, 1878 and Porania spinulosa Verrill, 1880, as infraspecific taxa within, rather than pure synonyms of, Poraniomorpha hispida (M. Sars). Marginaster austerus Verrill, 1899, in relation to M. pectinatus Perrier. Marginaster fimbriatus Sladen, 1889, in relation to Chondraster grandis (Verrill, 1878). Marginaster pentagonus Perrier, 1882, in relation to Poraniomorpha hispida borealis (Siissbach & Breckner). ASTEROIDEA 49 Sphaeriaster bjoerlykkei (Dons, 1938), in relation to Poraniomorpha hispida borealis (Siissbach & Breckner) and P. tumida (Stuxberg, 1878). Tylaster Danielssen & Keren, 1881, with type species T. willei Danielssen & Keren, 1881, in relation to Chondraster Verrill, 1895 and Porania Gray. Spoladaster Fisher, 1940, with type species Cryaster brachyactis H. L. Clark, 1923, in relation to Poraniomorpha Danielssen & Koren. Acknowledgements A particular debt is owed to Dr F. Jensenius Madsen, Universitetets Zoologisk Museum, Copenhagen, for extended consultation, examination of type material and provision of X-rays for comparison, though our conclusions as to taxonomic weighting of certain characters did not always coincide. Other X-rays were made in the British Museum by Mr G. Howes and Miss B. Brewster, Fish Section. I am also indebted to the following for provision of material for study: Mr D. Billett, Benthic Group, Institute of Oceanographic Sciences, Wormley; Miss S. Chambers, Royal Scottish Museum, Edinburgh; Miss M. E. Downey, United States National Museum, Smithsonian Institution, Washington, D.C.; Dr J. D. Gage, Scottish Marine Biological Association, Oban; Dr. Willard'D. Hartman, Peabody Museum, Yale, New Haven, Conn.; Dr B. Hecker, Lament- Doherty Geological Observatory, Palisades, New York; Mr M. Holmes, National Museum of Ireland, Dublin; Dr M. Sibuet, Centre Oceanologique de Bretagne, Brest; Dr G. Smaldon (formerly of) Royal Scottish Museum and Mr A. C. Wheeler, Fish Section, BM (NH). References Bell, F. J. 1893. Catalogue of the british echinoderms in the British Museum (Natural History). xvii + 202 pp. London: Trustees of the British Museum. Blake, D. B. 1980. On the affinities of three small sea-star families. Journal of Natural History. 14: 163-182. 1981. A re-assessment of the sea-star orders Valvatida and Spinulosida. Journal of Natural History. 15: 375-394. Cherbonnier, G. & Sibuet, M. 1973. Resultats scientifiques de la campagne Noratlante: Asteroides et Ophiurides. Bulletin du Museum National d'Histoire Naturelle, Paris. (Zoologie) No. 76 [1972]: 1333-1394. Clark, A. M. 1976. Asterozoa from Amsterdam and St Paul Islands, southern Indian Ocean. 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Memoire sur les etoiles de mer recueillies dans la Mer des Antilles et la Golfe de Mexique. Nouvelle Archives du Museum d'Histoire Naturelle, Paris (2)6: 127-276. 1 89 1 . Echinodermes. 1 . Stellerides. Mission Scientifique du Cap Horn. 1882-1883. 6: Zoologie. (3) 198 pp. Paris. 1893. Traite de Zoologie. 1 & 2. 864 pp. Paris: Librairie F. Savy. 1 894. Stellerides. Expeditions scientifiques du Travailleur et du Talisman. 43 1 . pp. Paris. Philippi, R. A. 1858. Beschreibung einiger neuer Seesterne aus dem Meere von Chiloe. Archiv Jur Naturgeschichte. 24: 264. Sars, M. 1872. Tillaeg. In: Sars, G. O. Nye Echinodermer fra den Norske Kyst. Forhandlinger i Videnskabsselskabet i Kristiania. 1871: 27-31. 1877. New echinoderms. In: Keren & Danielssen [Eds] Fauna littoralis Norvegiae. 3: 49-75. Bergen. Sladen, W. P. 1889. Asteroidea. Report of the scientific results of the voyage of H. M.S. Challenger, 1873-76. Zoology, 30: 1-935. Spencer, W. K. & Wright, C. W. 1966. Asterozoans. In: Moore, R. C. [Ed.] Treatise on Invertebrate Paleontology. U. Echinodermata 3(1): 4-107. Geological Society of America Inc.: University of Kansas Press. ASTEROIDEA 5 1 Stuxberg, A. 1878. Echinodermer fran Novaja Zemljashaf samlade under Nordenskioldska Expeditio- nerna, 1875 och 1876. Ofversigt af Kongl, Vetenskaps-Akademiens Forhandlingar. Stockholm. 1878(3): 27^0. Sussbach, S. & Breckner, A. 191 1. Die Seeigel, Seesterne und Schlangensterne der Nord- und Ostsee. Wissenschaftliche Meeresuntersuchungen der Kommission zur Wissenschaften Untersuchung der Deutschen Meere. Abteilung Kiel. N.S. 12: 167-300. Tortonese, E. 1965. Echinodermata. Fauna d'ltalia. 6: xv + 422. Bologna: Edizioni Calderini. Verrill, A. E. 1878. Notice of recent additions to the marine fauna of the eastern coast of North America. 1, 2. American Journal of Science. (3) 16: 207-215; 371-378. 1880a. Notice of recent additions to the marine Invertebrata of the northeastern coast of America. 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The larval and post- larval development of the Thumb-nail Crab, Thia scutellata (Fabricius), (Decapoda: Brachyura) R. W. Ingle Department of Zoology, British Museum (Natural History), Cromwell Road, London SW7 5BD Introduction The Thumb-nail crab, Thia scutellata (Fabricius) has been reported from the west coast of Sweden, off German, Belgium and Netherlands coasts, in the southern North Sea, from western sea areas of the British and Irish coasts, and southwards to the Mediterranean and west coast of Africa (see Christiansen, 1969; Ingle, 1980; Manning & Holthuis, 1981). The larval and early crab stages have been figured by Claus (1876), Cano (1892), Lebour (1928) and Williamson (1915). Except for Claus, these authors also gave very brief descriptions of stages, Williamson's being based on Claus' and Cano's figures; the accounts relate chiefly to plankton caught material and are somewhat superficial. In 1975 Mr T. Farrall, a Deputy Head of Langdon Park School, London, obtained two ovigerous crabs of T. scutellata from the Channel Islands while studying the relationships of this species with the Purple Heart Urchin, Spatangus purpureus O. F. Muller. The live crabs were donated to the British Museum (Natural History) and the eggs of one hatched on 18th September 1975. Sufficient material was reared through to fifth crab stage to enable a complete account to be given of the larval and early post- larval development of this species in the laboratory. Materials and methods The female, from which the larvae and post-larvae were reared, was collected near Vermerette Rock, Herm, Channel Islands in September 1975. The larvae were reared using methods described by Rice & Ingle (1975) and Ingle & Clark (1977). All material was fixed and stored in the preservative formulated by Steedman (1976: 148) and later transferred to 70% alcohol. Drawings and measurements were made with the aid of a camera lucida. Measurements are as follows: T. T. = total lengths of zoeae, measured between tips of dorsal and rostral spines; C. L. = carapace lengths, measured from between eyes to posterio- lateral carapace margin for zoeae, from rostral tip (for megalopa) and from frontal margin (for crab stage), to median posterior margin of carapace. The female and reared material are deposited in the Collections of the Zoology Department, British Museum (Natural History), registration number: 1983:312. Descriptions Thia scutellata (Fabricius, 1793) Thia polita: Claus, 1876: 56, Tav. X, figs 1-7 (1st zoea); Cano, 1892: 7, Tav. II, figs 16-26 (A-E) (lst-3rd zoeae, megal. 1st crab); Thia residuus: Williamson, 1915: 548-50, figs 470-479 (1st and later zoeae, megal. after Claus & Cano); Thia polita: Lebour, 1928: 528-9 (lst-4th zoeae, megal. 1st crab described), fig. 5 (17), PI. I, fig. 1 1 (2nd zoea, coloured), PI. VIII, figs 7-8 (3rd zoeae, megal. 1st, 2nd crab); Bourdillon-Casanova, 1960: 167. Bull. Br. Mus. nat. Hist. (Zool.) 47(1): 53-64 Issued 28 June 1984 53 54 R. W. INGLE FIRST ZOEA Dimensions: T. T. 2-70 mm, C. L. 0-70 mm. Carapace (Fig. la): Dorsal spine long and straight, stout proximally and narrowing distally; rostral spine thinner than dorsal and shorter; lateral spines about \ carapace length; dorso- median elevation present; carapace dorsal margin slightly elevated, a pair of prominent posterio- median setules present. Eyes: Partly fused to carapace. Antennule (Fig. 2b): Unsegmented, with 3 terminal aesthetascs and 2 setae. Antenna (Fig. 2f): Spinous process about 2^ x length of exopod, distal \ spinulate; exopod with 1 long and 1 short seta. Mandible (Fig. 2i): Incisor not differentiated from molar process. Maxillule (Fig. 21): endopod 2-segmented, with 1,6 setae; basal endite with 5 and coxal with 7 setae/spines. Maxilla (Fig. 3c): endopod with broad outer and narrower inner lobe with 5 + 3 setae; basal endite with outer lobe slightly broader than inner, with 4 + 5 setae; coxal endite with outer lobe slightly broader than inner, with 4 + 3 setae; scaphognathite with 4 plumose setae and a very stout posterior plumose projection. First maxilliped (Fig. 4a): Basis with 10 setae arranged 2,2,3,3; endopod 5 -segmented with 2,2,1,2,4+ 1 setae; exopod incipiently segmented with 4 terminal plumose setae. Second maxilliped (Fig. 4c): Basis with 4 setae; endopod 3-segmented with 1,1, 3 + 1 setae; exopod with 4 terminal plumose setae. Third maxilliped: Not developed. Pereiopods: Not developed. Abdomen (Figs le, 2a): 5 segmented + telson; 2nd segment with a pair of dorso- lateral pro- cesses; posterio- lateral margin of 1st truncate, of 2nd-5th rounded to sub-acute and minutely spinulate. A pair of small setae near posterio-dorsal margin of segments 2-5. Telson forks long and thin, each with thin long lateral and dorsal spine; inner medio-lateral margin of telson with 6 setae all similarly plumed; median margin of telson strongly concave. SECOND ZOEA Dimensions: T. T. 3-1 mm, C. L. 0-75 mm. Carapace (Fig. Ib): Posterior margin with 3-4 long setules; two pairs of dorso- median setae now present. Eyes: Now stalked. Antennule (Fig. 2c): Now with 6 acesthetascs and 1 seta. Antenna: Unchanged. Mandible: Unchanged. Maxillule (Fig. 2m): Endopod setation unchanged; outer margin of basal endite with a promi- nent plumose seta, dorso-inner margin with 9 setae/spines; coxal setation unchanged. Maxilla (Fig. 3d): endopod setation unchanged; basal endite with 5 + 5 setae and additional seta in some specimens (some distance from margin); coxal setation unchanged; scaphognathite with 1 1 plumose marginal setae. First maxilliped: Basal and endopod setation unchanged; exopod with 6 terminal plumose setae. Second maxilliped (Fig. 4d): Basal setation unchanged; endopod with 1,1,4+1 setae; exopod with 6 terminal plumose setae. Third maxilliped: Not developed. Pereiopods: Not developed. Abdomen (Fig. If): Sixth segment incipient; 1st segment with dorso- median setule; dorsal- lateral processes on 2nd segment less acute and not curved. Inner medio-lateral margin of telson with additional pair of small setules; lateral spine on telson reduced to a very minute setule. BRACHYURA 55 THIRD ZOEA Dimensions: T. T. 3-8 mm, C.L. 1, 30 mm. Carapace (Fig. Ic): Posterior margin with 5 long setules; three pairs of dorso-median setae now present. Eyes: Unchanged. Antennule. (Fig. 2d): two or 3 of the 6 aesthetascs now sub-distal. Antenna (Fig. 2g): Spinous process slightly less than 3 x length of exopod; endopod now developed as a conspicuous bud. Mandible (Fig. 2j): Incisor and molar processes now differentiated. Maxillule (Fig. 3a): Endopod setation unchanged; basal endite with 11 and coxal with 10 setae/spines. Maxilla (Fig. 3e): Endopod, basal and coxal endite setation unchanged; scaphognathite with 18 setae. First maxilliped (Fig. 4b): Basal setation unchanged; endopod terminal segment now with 5 + 1 setae; exopod with 8 terminal plumose setae. Second maxilliped: Basal and endopod setation unchanged; exopod with 8 terminal plumose setae. Third maxilliped: Represented as a small bud. Pereiopods: now represented as small buds. Abdomen (Fig. Ig): Sixth segment now fully differentiated; first segment with 3 conspicuous dorso-median setules; innermost pair of medio- lateral setules on telson much longer than in previous stage; pleopods represented as conspicuous buds on segments 2-5. FOURTH ZOEA Dimensions: T.T. 4-6 mm, C.L. 1-60 mm. Carapace (Fig. Id): Dorsal and rostral spines stouter than in previous stage and lateral spines smaller; posterior margin of carapace with 11-12 setules. Eyes: Unchanged. Antennule (Fig. 2e): Incipiently 2-3 segmented, ultimate segment with 2 aesthetascs and 1 seta, penultimate with 7 distal and 2 sub-distal aesthetascs; endopod bud developed. Antenna (Fig. 2h): Spinous process about 2^x length of exopod; innermost terminal seta of exopod very long; endopod bud very long. Mandible (Fig. 2k): Now with incipient palp. Maxillule (Fig. 3b): Endopod setation unchanged; basal endite now with 16 setae/spines; coxal setation unchanged. Maxilla (Fig. 3f): Endopod setation unchanged; basal endite with 6 + 6-7 setae; coxal setation unchanged. First maxilliped: Basal and endopod setation unchanged; exopod with 10 distal plumose setae. Second maxilliped: Basal and endopod setation unchanged; exopod with 10 distal plumose setae. Third maxilliped: now bilobed. Pereiopods: longer than previous stage and cheliped dactylus differentiated. Abdomen (Fig. 1 h): Dorsal surface of telson with a pair of small setules; pleopod buds well developed, longer than in previous stage. MEGALOPA Dimensions: C.L. 2-2 mm. Carapace (Fig. 4e,f): Longer than broad; frontal region broad, margins almost parallel; a small median furrow near rostral base; rostrum slightly deflected ventrally; cardiac region with suggestion of a broad tubercle; posterior margin with numerous setae. Eyes: Large. Antennule (Fig. 5a): Peduncle 3-segmented, setose as shown exopod incipiently 3-segmented, with 4,4,4,-5 aesthetascs and 0,1,2 setae respectively; endopod incipiently 2-segmented with 5 terminal setae. 56 R. W. INGLE Antenna Fig. 5b): Peduncle 3 -segmented, with 0,2,1 setae respectively; flagellum 8-segmented with 4,0,2,0,4,0,3,4 setae respectively. Mandible (Fig. 5c,d): Molar and incisor processes not differentiated; mandibular palp (d) 3-segmented, terminal segment long and slightly curved, with 8 setules. Maxillule (Fig. 5e): Endopod long and unsegmented, with 2 sub-terminal and 2 terminal setae all reduced; basal endite with 23-24 setae/spines; coxal endite still with 10 setae/spines. Maxilla (Fig. 50: Endopod now reduced to a sub-acute lobe with 1-2 setae; basal endite with 7 + 7 setae, coxal still with 4 + 3 setae; scaphognathite with 4 1-42 plumose setae, shorter than in last zoeal stage. First maxilliped (Fig. 5g): Coxal and basal segments slightly differentiated coxal with 1 1-12 setae on or near inner margin; basis with 28-29 setae; endopod unsegmented and with 3 distal setae; exopod 2-segmented, distal segment with 3 terminal setae; epipod (not shown) with 3-4 setae. Second maxilliped (Fig. 5h): Coxal and basal segments undifferentiated; endopod with only propodus and dactylus demarcated, propodus with 6 setae, dactylus with 5 spines + 1 seta; exopod 2-segmented, distal segment with 3 setae; epipod (not shown) short, with 2-3 setae. Third maxilliped (Fig. 5i): Inner margin of coxa with 1 and basis with 4 setae; inner margin of ischium with 3-4 small denticles and with 10-11 setae, carpus-dactylus with 7,5,6,4-5 setae respectively; epipod (not shown) long and with 10-11 setae. Pereiopods (Fig. 6a-f): Cheliped stout, setose as shown, propodal palm inflated, inner pro- podal and dactylar margins cut into irregular teeth (b); cheliped without coxal or ischial spines. Pereiopods 2-5 (c-f) short and stout, setose as shown, dactyls terminally very acute and those of 5th with 2 long terminal simple setae in addition to 3 prominent, slightly shorter ones on lower margin. Abdomen (Fig. 4g,h, 6g): With 6 segments + telson and setose as shown, posterio- lateral mar- gins broadly truncate. Telson (Fig. 6g) truncate, about as broad as long, dorsal surface with 2 pairs of median setules. Five pairs of pleopods, exopods with long plumose marginal setae, 1st (Fig. 6h) with 13, 2nd 15, 3rd 14, 4th (Fig. 6i) 11, 5th (uropod, Fig. 6g) with 8 setae respectively; endopods of pleopods 1-4 each with 3 distally placed coupling hooks on internal margins. FIRST CRAB Dimensions: C.L. 2-54 mm. Carapace (Fig. 6j): Longer than broad, frontal region projecting; four pairs of anterio- lateral teeth, lst-3rd acute, 4th small and obtuse. Dorsal surface of carapace smooth and anteriorly with minute setules; margins with well developed plumose setae. Remarks The present laboratory reared material of Thia scutellata agrees in most aspects with pre- vious accounts of the larval and post-larval descriptions of this species (see p. 53), except in the following features. (1) The maxillule of the 1st zoea figured by Claus (1876) shows 1 + 5 setae on the endopod and 4 on the coxa and the setal formula for the maxilla is given as 5 + 2, 3+4, 2 + 3 for endopod, basis and coxa respectively; Claus also figured an incipient 3rd maxilliped in this 1st stage zoea. (2) Lebour (1928) depicts 2 dorsal setules on the 1st abdominal segment of the 3rd zoea whereas all the present specimens have 3 setules. (3) Lebour did not examine 1st stage zoeae and assumed that only one spine was present on each telson fork in this stage although Claus clearly shows two spines in his figure of the 1st zoea. In the present material the lateral spine is minute from the 2nd zoeal stage onward. However, Cano (1892) depicted two prominent spines on the telson forks of the zoea that he attributed to the 3rd stage of T. scutellata. (4) In all previously published figures of the 1st crab stage the carapace anterio-lateral margins are shown as more prominent than observed in the present material and Lebour figured these margins as somewhat irregular in outline. BRACHYURA 57 The zoea of Thia scutellata can be distinguished from those of other brachyrhynchs (except perhaps Atelecydus, see below) described from NE. Atlantic waters on the following com- bined features. (1) Lateral spines on carapace. (2) Dorso- lateral processes confined to 2nd abdominal segment. (3) Two setae on basal segment of 1st maxilliped endopod. (4) Lateral spine on telson forks reduced to a very minute setule in 2nd-4th stages. The megalopa of T. scutellata is less easy to recognize because this stage is inadequately described for many species of NE. Atlantic brachyrhynchs. T. scutellata megalopa has the following combined features. (1) Absence of coxal or ischial spines on the pereiopods. (2) Sternites without spines. (3) Absence of tubercles or spines on carapace. (4) Uropod with 8 setae. (5) The two long terminal setae on the dactylus of the fifth pereiopod have simple apices. Lebour (1928: 528) proposed the family name Thiidae for Thia polita, stating that this species is 'different in many ways, and its larval stages does not fit into any family, although apparently near the Cancridae and the Corystidae'. The family name is now accredited to Dana 1852. Rice (1980: 333), basing his remarks on Lebour's account, suggested that Thia is possibly more closely allied to Corystes than to cancrids or portunids but was unable to comment further because of the absence of adequately described material. The zoeae of T. scutellata have two setae on the basal segment of the first maxilliped endopod, six setae on the distal segment of the maxillule, ten setae on the basis of the first maxilliped, lateral spines on the carapace, 5 + 3 setae on maxilla endopod and the dorso-lateral processes confined to the second segment of the abdomen. These features place them near to the Portunidae and in this respect they key satisfactorily to that part of the key to the brachyuran families as constructed by Rice (1980: 360). Differences separating zoeae of Thia from Atelecydus must await a critical re-examination of zoeae of A. rotundatus since the character listed by Lebour (1928: 487) for separating zoeae of these two genera, i.e. the presence of only one spine on the telson forks in Thia, is no longer valid. Addendum Mr Jose Paula, Faculdade de Ciencias, Lisbon, has recently informed me that a minute third spine is present on the outer telson fork of T. scutellata zoeae collected in Portuguese waters. A re-examination of the present reared material has revealed that this third lateral spinule is just discernible in some specimens. Acknowledgements I wish to express my sincere thanks to Mr T. Farrall for kindly providing the ovigerous specimens of T. scutellata and to Dr A. L. Rice for reading the manuscript. References Bourdillon- Casanova, L. 1960. Le meroplancton du Golfe de Marseille; les larves de crustaces decapodes. Recueil des Travaux de la Station Marine d'Endoume. 30: 1-286. Marseille. Cano, G. 1982. Sviluppo postembrionale dei Dorippidea, Leucosiadi, Corystoidei e Grapsidi. Memoire della Societa Italiana della Scienze delta dei XL. 8(3) 4: 1-14 Roma. Christiansen, M. E. 1969. Marine invertebrates of Scandinavia. No. 2, Crustacea, Decapoda, Brachyura. Universitetsforlaget 143 pp. Oslo. Claus, C. 1876. Untersuchungen zur Erforschung der Genealogischen Grundlage des Crustaceen- Systems. i-viii + 1 14 pp. Wien. Ingle, R. W. 1980. British Crabs. Oxford University Press & British Museum (Natural History) 222 pp. Oxford & London. & Clark, P. F. 1977. A laboratory module for rearing crab larvae. Crustaceana. International Journal of Crustacean Research. 32: 220-222 Leiden. Lebour, M. V. 1928. The larval stages of the Plymouth Brachyura. Proceedings of the Zoological Society of London. 2: 473-560. London. 58 R. W. INGLE Manning, R. B. & Holthuis, L. B. 1981. West African Brachyuran Crabs (Crustacea: Decapodd). Smithsonian Contributions to Zoology i-xii + 379 pp. Washington, D.C. Rice, A. L. 1980. Crab zoeal morphology and its bearing on the classification of the Brachyura. Transactions of the Zoological Society of London 35: 271-424 London. & Ingle, R. W. 1975. The larval development of Carcinus maenas (L.) and C. mediterraneus Czerniavsky (Crustacea, Brachyura, Portunidae) reared in the laboratory. Bulletin of the British Museum (Natural History) (Zoology) 28: 101-119 London. Steedman, H. F. (ed.) 1976. Zooplankton fixation and preservation. In: Monographs on oceanographic methodology. 350 pp. Paris. Williamson, H. C. 1915. VI. Crustacea Decapoda Larven. Nordisches Plankton 18: 315-558. Kiel. Manuscript accepted for publication 18 October 1983 Fig. 1 (p. 59) Thia scutellata (Fabricius): a-d, right lateral aspecies of lst-4th zoeae; e-h, abdomens from dorsal aspects of lst-4th zoeae. Scale (e-h) = 0-1 mm. Fig. 2 (p. 60) Thia scutellata (Fabricius): a, lateral margins of abdominal segments 1-5 of 1st zoea; b-e, antennules of lst-4th zoeae; f-h, antennae of 1st, 3rd & 4th zoeae; i-k, mandibles from dorsal aspects of 1st, 3rd and 4th zoeae; 1, m, maxillules of 1st & 2nd zoeae. Scales = 0-1 mm, a, 1, m to lower; i-k to middle; b-h to upper scale. Fig. 3 (p. 61) Thia scutellata (Fabricius): a, b, maxillules of 3rd & 4th zoeae; c-f, maxillae of lst-4th zoeae. Scale = 0-1 mm. Fig. 4 (p. 62) Thia scutellata (Fabricius): a, 1 st maxilliped of 1 st zoeae; b, 1 st maxilliped, terminal segments of 3rd zoeae; c, d, 2nd maxillipeds of 1st & 2nd zoea; e, dorsal aspect of megalopa; f, carapace of megalopa from right lateral aspect; g,h, abdomen from dorsal and right lateral aspects. Scales =0-1 mm, g,h to upper; a, c, d, to middle; b to lower. Fig. 5 (p. 63) Thia scutellata (Fabricius): megalopa: a, antennule; b, antenna c, ventral aspect of mandible; d, dorsal aspect of mandibular palp; e, maxillule; f, maxilla; g-i, lst-3rd maxil- lipeds. Scales = 0- 1 mm, g-i to uppermost; b to second; a to third; c, e, f to fourth; d to lowermost scale. Fig. 6 (p. 64) Thia scutellata (Fabricius): a-i, megalopa; a-f, lst-5th pereiopods; g, telson and uropods from dorsal aspects; h, i, 1st, 4th pleopods; j, carapace of 1st crab. Scales = 0-1 mm, a, c-f to upper; b, to middle; h, i to lower scale. Fie. 1 Fie. 2 Fi Fig. 4 Fie. 5 Description of a new species of Sylvisorex (Insectivora: Soricidae) from Tanzania Paulina D. Jenkins Department of Zoology, British Museum (Natural History), Cromwell Road, London SW7 5BD Introduction Two species of Sylvisorex are known from Tanzania, S. granti Thomas, 1907 which has been reported from Mount Kilimanjaro and S. megalura (Jentink, 1888) of which specimens from three separate localities have been recorded recently by Howell & Jenkins (in press). In the course of organised collecting in Tanzania, Dr K. M. Howell of the University of Dar-es- Salaam obtained a number of shrews which were submitted to the British Museum (Natural History) for identification. These include a single example of Sylvisorex which on examin- ation proves to differ substantially from all the known species of the genus in size and dental morphology, which is described here as new. The specimen differs externally from other members of the genus in the presence of bristle- hairs on the tail. The absence of such bristle- hairs has been used to distinguish Sylvisorex from Suncus but this distinction must now depend on the cranial differences elaborated by Heim de Balsac & Lamotte (1957) plus the dental characters used by Repenning (1967) and Butler & Greenwood (1979). The most readily applied of these latter characters is the presence of denticulations on the cutting surface of the first lower incisor in Sylvisorex, which are lacking in Suncus; also in Sylvisorex the talon of the upper premolar is more highly developed, the interorbital region broader and the braincase broader and higher relative to skull size. Additionally the hindfeet in Sylvisorex are larger relative to body size with slightly elongated, staggered, separated, metatarsal pads, while Suncus has smaller hindfeet with more oval, more or less adpressed pads. All measurements are in millimetres: the dental nomenclature follows that of Swindler (1976), Butler & Greenwood (1979) and is illustrated in Figure 1. Systematic Section Sylvisorex howelli sp. nov. HOLOTYPE. BM(NH) 82.874 adult of undetermined sex (viscera and external genitalia removed) in alcohol, skull removed; collected 27 April 1982 on Bondwa Peak, Uluguru North Forest Reserve, Uluguru Mountains, Morogoro District, Tanzania, c. 0654'S 3740'E, c. 1050m on road through forest by M. K. S. Maige and donated by Dr K. M. Howell. DIAGNOSIS. Small, size intermediate between S. johnstoni (Dobson, 1888) and S. granti; tail with bristle-hairs; braincase shallow and long, relative to skull length; lingual edge of second upper unicuspid projecting beyond that of first, level with lingual edge of third unicuspid; crown area of fourth upper unicuspid smaller than crown area of second upper unicuspid; parastyle of upper premolar low and slender; posterolingual ridge on first lower incisor very prominent, forming a small cusp; talonid of third lower molar reduced. (See Figs 2-8). Bull. Br. Mm. nat. Hist. (Zool.) 47(1): 65-76 Issued 28 June 1984 65 66 P. D. JENKINS (a) buccal cingulum lingual cingulum parastyle protocone paracone distostyle parastyle hypocone metastyle (b) posterior ridge protostylid on posterior ridge metaconid on posterolingual ridge posterolingual ridge posterolingual cingulum anterolingual ridge (c) protoconid paraconid metaconid hypoconid talonid basin entoconid ridge entoconid Fig. 1 Diagrams to show cusp nomenclature: (a) crown view of left upper third and fourth unicuspids, premolar and first molar; (b) lingual view of right lower first and second incisors and premolar; (c) lingual view of right lower third molar. DESCRIPTION. Size small (head and body length 48, tail length 44-5, hindfoot length without claws 11-5, ear length 6-8); dorsally dark brown, the hairs basally grey but brown medially and terminally; ventral pelage paler brown, the hairs with light grey bases and light brown tips; a gradual transition along flanks between colour of dorsum and venter; ears, limbs and dorsal surface of tail dark brown, their ventral surfaces paler, lacking any sharp lateral demarcation; the tail with a cover of short hairs along its entire length, interspersed with longer bristle hairs on the basal two-thirds. INSECTIVORA 67 Fig. 2 Dorsal view of skulls of Sylvisorex. Top row from left to right: S. johnstoni, S. howelli, S. granti and S. megalura; lower row from left to right: S. morio, S. lunaris and S. ollula. Scale in mms. Skull small (see Table 1), mostly lacking any exceptional features, but cranial profile sloping gradually upwards from tip of rostrum to posterior part of inter-orbital region then sloping more steeply to a rounded braincase which is long, not especially broadened and shallower relative to skull length than in other members of the genus (Figs 2-4); mandible with short, broad ascending ramus (Fig. 5). Posterior portion of upper incisor (I 1 ) only slightly wider than remainder of tooth, the dis- tance between posterior part of incisors just greater than the width of one incisor. First upper unicuspid (Un 1 ) sub-oval, with straight-edged lingual cingulum, tapering anteriorly and lacking any posterior cingular ridge; second upper unicuspid (Un 2 ) with broad lingual cingulum, approximately twice as broad as buccal cingulum, its lingual edge projecting beyond that of Un 1 and level with that of third upper unicuspid (Un 3 ); Un 3 with broad lingual cingulum, the tooth tapering anteriorly and rounded in crown view; fourth upper unicuspid (Un 4 ) with broad lingual cingulum, the tooth almost round in crown aspect and smaller than Un 2 . Parastyle of upper premolar (P 4 ) low and slender; talon posteriorly and lingually expanded, its posterior edge level with distostyle; least internal distance between premolars (P 4 -P 4 ) approximately three-quarters of the width of one premolar. Talon of first and second 68 P. D. JENKINS Fig. 3 Ventral view of skulls of Sylvisorex. Top row from left to right: 5. johnstoni, S. howelli, S. granti and S. megalura; lower row from left to right: S. morio, S. lunaris and S. ollula. Scale in mms. upper molars (M 1 and M 2 ) only slightly expanded lingually, its lingual edge straight but expanded posteriorly, so that its posterior edge is level with metastyle. Third upper molar (M 3 ) with a long ridge between parastyle and paracone, the ridge between paracone and protocone and that between metacone and mesostyle short, angle between protocone, meta- cone and midline of palate shallow; talon well-developed. Lower incisor (I,) long, slightly curved and approximately the same vertical diameter (in lateral aspect) for most of its length, tapering gradually to its tip; two rounded elevations on posterior ridge, anterior elevation long and low; posterolingual ridge prominent, forming a small cusp, higher than posterior ridge; lingual enamel extension reaching level of protoconid of second lower incisor (I 2 ); lingual groove extending along length of tooth and terminating just anteriorly to notch at base of lateral enamel extension; anterolingual ridge present but poorly developed, not extending onto lateral enamel extension; no posterolingual cingulum. I 2 anteroposteriorly slightly lengthened; posterolingual ridge well-developed; no protostylid. Posterior ridge of fourth lower premolar (P 4 ) lacking protostylid; metaconid on posterolingual ridge barely marked. Anterior ridge of entoconid of first and second molars (M, and M 2 ) poorly developed, not divergent from lingual side of tooth, the entoconid conical; postentoconid INSECTIVORA 69 e I a: E 11 o.S "*. co - c g o ^ 3 f -^-t *^** Ji 05 S.2 o s I ^- **- DC - 70 P. D. JENKINS Fig. 5 Lateral view of mandibles of Sylvisorex. Top two rows, above lingual view of right man- dibular ramus, below labial view of left mandibular ramus, from left to right: S. johnstoni, S. howelli, S. granti and S. megalura; lower two rows, above lingual view of right mandibular ramus, below labial view of left mandibular ramus, from left to right: S. morio, S. lunaris and S. ollula (left mandibular ramus absent). Scale in mms. ledge present, adjacent to base of entoconid; lingual cingulum of M, weakly developed anter- iorly, absent from M 2 ; the buccal cingulum continuing round hypoconid and merging with posterolingual rib on M, but on M 2 narrow and merging with posterior part of hypoconid. Talonid of third lower molar (M 3 ) reduced, the talonid basin reduced, the entoconid and the posterolingual rib absent but an entoconid ridge present. ETYMOLOGY. The name of the new species is derived from that of Dr K. M. Howell of the University of Dar-es-Salaam, who kindly donated this specimen. Comparison with other species Key to the species of Sylvisorex 1. Large, condylobasal length (CBL)>23, upper toothrow length (UTL)> 10 S. ollula Smaller, CBL <23, UTL< 10 2. Larger, CBL > 18, UTL>8 Smaller, CBL< 18, UTL< 8 3. Larger, CBL > 20, UTL>9, talonid of third lower molar (M 3 ) more reduced than that of second lower molar (M 2 ), third upper molar (M 3 ) anteroposteriorly compressed, < 7-5% ofUTL S. lunaris Smaller, CBL < 20, UTL<9, talonid of M 3 similar to that of M 2 , M 3 not anteroposteriorly compressed, > 9% of UTL S. morio 4. Tail longer than head and body, braincase narrow, braincase breadth (BB) <48% of CBL .V. megalura Tail equal to or shorter than head and body, braincase broader, BB>48% of CBL INSECTIVORA 71 Fig. 6 (a-d) Crown view of left upper unicuspids: (a) S. johnstoni; (b) 5". howelli; (c) S. granti; (d) S. megalura. (e-f) Labial view of left upper second, third and fourth unicuspids and pre- molar: (e) S. granti; (f) S. howelli. Scales 1 mm. 5. Small, CBL< 15, UTL up to 6-5, M 3 anteroposteriorly compressed, <8% ofUTL, talonid of M 3 reduced to a single cusp S. johnstoni Larger, CBL> 15, UTL>6-5, M 3 not anteroposteriorly compressed, >8% of UTL, talonid of M 3 less reduced 6. Tail lacking bristle-hairs, braincase deep, braincase height (BH) 4-5-5-0, >27% of CBL, talonid of M 3 similar to that of M 2 S. granti Tail with bristle-hairs, braincase shallow, BH 4-1, <27% of CBL, talonid of M 3 reduced but talonid basin and entoconid ridge present. 5. howelli S. howelli is intermediate in size between the smaller S. johnstoni and the slightly larger S. granti but smaller than all other members of the genus (Table 1 & Figs 2-5). S. morio (Gray, 1862) S. lunaris Thomas, 1906 and S. ollula Thomas, 1913 are readily distinguished from S. howelli by their much greater size and require no further detailed comments; their measurements are included in table 1 for comparative purposes. 72 P. D. JENKINS Fig. 7 (a-d) Lingual view of right lower first and second incisors, (e-h) Lingual view of right lower premolar and first and second molars, (a & e) S. johnstoni; (b & S". howelli; (c & g) S. granti; (d & h) S. megalura. Scales 1 mm. The skull of S. howelli has a moderately broad, shallow, long braincase relative to skull length, in comparison with other members of the genus (Table 2 & Figs 2-4). S. johnstoni has a broad, moderately deep and long braincase; S. granti has a broad, deep, moderately long braincase and S. megalura a narrow, moderately deep and long braincase. INSECTIVORA 73 Fig. 8 Lingual view of right lower third molar: (a) S. johnstoni; (b) S. howelli; (c) S. granti; (d) S. megalura. Scales 1 mm. The ascending ramus of the mandible is rather short and broad in S. howelli (Fig. 5). The ramus in S. johnstoni is high and narrow. Height of the ascending ramus at the coronoid process is less in S. howelli than in S. granti or S. megalura (Table 1). The dentition of S. howelli is distinctive (see description). The main differences between the four species are illustrated in figures 6-8 and discussed below. The degree of development of the lingual cingulum on the upper unicuspids varies from broad in S. johnstoni and S. granti to very broad in S. megalura and S. howelli (Fig. 6). In S. howelli the lingual edge of the second upper unicuspid projects beyond that of the first and is level with that of the third, while in the other three species the lingual edge of the second upper unicuspid does not project as far as that of the first and third unicuspid. The parastyle of the upper premolar is low and slender in S. howelli but medium in height and well developed in the other three species. S. granti is illustrated as an example of the condition in all three species in comparison with S. howelli (Fig. 6). The third upper molar is a large tooth in S. granti and S. megalura, it is somewhat smaller in S. howelli but is anteroposteriorly compressed in S. johntoni (Table 1). The posterolingual ridge of the first lower incisor (Ij) is higher than the posterior ridge and forms a small cusp in S. howelli, unlike the condition in the other three species (Fig. 7). The anterolingual ridge of I, does not extend onto the lateral enamel extension and a posterolingual cingulum is absent in S. johnstoni and S. howelli. In S. granti and S. megalura there is a well developed anterolingual ridge, extending onto the lateral enamel extension to form a posterolingual cingulum. 74 P. D. JENKINS T '_' OX r*l iA s; .3 CO o ooS * CO CO -s: co o rn o R -s: ^ CO 1 *o m^ >nrn 2^ lo*^ ONr-~ C IX C IX C |X C |X C IX C IX C a xi _o TJ o U op OJ | D 1 1 1 o - o- tli X INSECTIVORA 75 Table 2 S. johnstoni S. howelli S. granti S. megalura Braincase breadth 7-0-7-5 7-7 8-0-8-6 7-6-8-1 X 7-30 8-28 7-84 n 7 1 11 9 Braincase height 3-8-4-0 4-1 4-5-5-0 4-4-4-7 X 3-87 4-75 4-55 n 7 1 11 9 Braincase length 5-6-5-8 6-8 6-6-7-1 6-8-7-4 X 5-73 6-85 7-11 n 7 1 11 9 Braincase breadth as 49-0-54-0 48-4 49-1-51-9 43-7-47-6 a % of condylobasal X 51-38 50-48 46-01 length n 7 1 11 9 Braincase height as 26-6-28-1 25-8 27-5-30-9 25-9-28-3 a % of condylobasal X 27-24 28-92 26-69 length n 7 1 11 9 Braincase length as 39-6-41-1 42-8 40-7-42-6 40-8-42-0 a % of condylobasal X 40-31 41-72 41-70 length n 7 1 11 9 x^mean; n = sample size. A posterolingual ridge is present on the second lower incisor of S. howelli, it is weakly developed in S. granti and S. megalura but absent from S. johnstoni (Fig. 7). There is no protostylid and a metaconid is barely indicated on the lower premolar of S. howelli; both protostylid and metaconid are lacking in S. johnstoni; both protostylid and metaconid are present in S. granti, while a metaconid only is present in S. megalura (Fig. 7). In all three species except S. howelli, a small cusplet is present in the posterior part of the valley between the posterior ridge and the posterolingual ridge. The talonid of the third lower molar is reduced to a single cusp, the hypoconid, in S. johnstoni (Fig. 8). It is reduced to a small talonid basin and an entoconid ridge in S. howelli. In S. granti and S. megalura less reduction has occurred and the talonid resembles that of the second lower molar. Acknowledgements I should like to thank Dr K. M. Howell of the University of Dar-es-Salaam who has donated a number of shrews to this museum, including the specimen of the new species. I am also grateful to Mr J. E. Hill and Mr I. R. Bishop O.B.E. of the Mammal Section, British Museum (Natural History) for their helpful criticism of the manuscript. References Butler, P. M. & Greenwood, M. 1979. Soricidae (Mammalia) from the early Pleistocene of Olduvai Gorge, Tanzania. Zoological Journal of the Linnaean Society 67: 329-379, 18 figs. Dobson, G. E. 1888. On the genus Myosorex, with descriptions of a new species from the Rio del Rey (Cameroons) District. Proceedings of the Zoological Society of London (1887) (4): 575-578. Gray, J. E. 1862. List of mammalia from the Camaroon (Sic.) Mountains, collected by Capt. Burton, H. M. Consul, Fernando Po. Proceedings of the Zoological Society of London (2): 180-181, pi. 24. Jentink, F. A. 1888. Note 1. Zoological researches in Liberia, a list of mammals, collected by J. Biittik- ofer, C. F. Sala and F. X. Stampfli. Notes from the Leyden Museum 10: 1-58, pis. 1-4. 76 P. D- JENKINS Heim de Balsac, H. & Lamotte, M. 1957. Evolution et phylogenie des soricides Africains 2. La lignee Sylvisorex-Suncus-Crocidura. Mammalia 21(1): 15-49. Howell, K. M. & Jenkins, P. D. (in press). Records of shrews (Insectivora, Soricidae) from Tanzania. African Journal of Ecology. Repenning, C. A. 1967. Subfamilies and genera of the Soricidae. Professional Papers of the United States Geological Survey (565): 1-74. Swindler, D. R. 1976. Dentition of living primates. London, New York, San Francisco. Thomas, M. R. O. 1906. Descriptions of new mammals from Mount Ruwenzori. Annals and Maga- zine of Natural History (7) 18: 136-147. 1907. On further new mammals obtained by the Ruwenzori Expedition. Annals and Magazine of Natural History (7) 19: 1 18-123. 1913. On African bats and shrews. Annals and Magazine of Natural History (8) 11: 314-321. Manuscript accepted for publication 21 October 1983 A new species of the Hipposideros bicolor group (Chiroptera: Hipposideridae) from Thailand J. E. Hill Department of Zoology, British Museum (Natural History), Cromwell Road, London SW7 5BD, United Kingdom Songsakdi Yenbutra Thailand Institute of Scientific and Technological Research, Bangkhen, Bangkok 9, Thailand While Curator of Terrestrial Vertebrates at the Thai National Reference Collection (now a part of the Thailand Institute of Scientific and Technological Research) the late Kitti Thonglongya undertook a survey of the bats of Thailand and their associated parasites, col- lecting extensively throughout the country. For the most part the bats that he collected were reported on the basis of a broad sample by Hill (1975). Those sent to London for examination included an example of Hipposideros from Rat Buri (TNRC 54-2080, now BM(NH) 78.2344) initially referred to H. ater Templeton, 1 848 but which proved to diifer quite clearly either from this species or from H. cineraceus Blyth, 1853 which in some superficial respects it resembled. No further study was undertaken at the time, Hill (1975) listing it as Hipposideros sp. but noting that it could not be referred to ater or to cineraceus from which it differed in certain features of the noseleaf and skull, or in size. Further similar specimens have now been found in the Thai National Reference Collection and more detailed study has established that all represent an undescribed species: additionally, another example in London (BM(NH) 78.2346, formerly TNRC 54-1961) proves also to represent the new species, rather than H. cineraceus as was thought originally. Hipposideros halophyllus sp. nov Hipposideros sp.: Hill, 1975: 27, Rat Buri, Thailand. Hipposideros cineraceus: Hill, 1975: 29 (in part), Phet Buri, Thailand; Lekagul & McNeely, 1977: 165 (in part), fig. 6 1 . HOLOTYPE. rf TNRC 54-3694. Khao Sa Moa Khon, Tha Woong, Lop Buri, Thailand. Collected by Kitti Thonglongya. In alcohol, skull extracted, rear of cranium slightly damaged. OTHER MATERIAL EXAMINED IN LONDON, rfd 1 , 9 TNRC 54-3696, 54-3697, 54-3705. All from the type locality. In alcohol, skulls extracted. rf BM(NH) 78.2344. Tham Khao Bin, Rat Buri, Thailand. Originally TNRC 54-2080. In alcohol, skull extracted. d 1 BM(NH) 78.2346. Tham Khao Yoi, Phet Buri, Thailand. Originally TNRC 54-1961. Skin and skull. OTHER MATERIAL EXAMINED IN BANGKOK. 33 TNRC 54-3695, 54-3706, 99 TNRC 54-3704, 54-3710. All from the type locality. In alcohol, skulls of TNRC 54-3695, 54-3710 extracted. DIAGNOSIS. A member of the bicolor group (Hill, 1963) of Hipposideros, characterized exter- nally by large rounded ears lacking any sharply defined point or any definite fold or thicken- ing at the antitragal lobe; by the absence of lateral supplementary leaflets beneath the an tero- lateral margin of the anterior leaf, which has a shallow median emargination, and by the expansion of the internarial septum to form a small, disc-like structure just anterior Bull. Br. Mus. nat. Hist. (Zool.) 47(1): 77-82 Issued 28 June 1984 77 78 J. E. HILL & S. YENBUTRA to the nostrils. The skull is elongate and narrow, the zygomatic width less than the mastoid width, the braincase moderately inflated anteriorly, with a low, narrow rostrum, broad basis- phenoid depression and wide basioccipital, the tympanic bullae long and narrow and the inflated part of the cochleae elongate rather than subcircular. The new species is similar in size and ear structure to Hipposideros cineraceus or to H. ater but may be distinguished by its internarial structure and elongate tympanic bullae. Among other Asian species it has some resemblance to H. ridleyi in the disc-like expansion of the internarial septum but ridleyi is much larger (length of forearm c. 48 mm) and its internarial disc is relatively much larger, thinner and more saucer-like. DESCRIPTION. Small (length of forearm 35-1-38-2 mm). Ears large, broad and rounded with broad, poorly defined tip, the anterior margin strongly convex, lacking any basal lobe, the posterior margin of the ear slightly convex for much of its length, deflected sharply to a wide, anteriorly rectangular antitragal lobe; a very slight thickening of the integument of the ear at the rear of the antitragal lobe but no definite fold or obvious antitragal modification. Outer (medial) surface of conch haired for about one half or a little more the length of the ear, the hairs proximally rather dense and long, more distally sparser and shorter; a sparse scattering of short hairs along the anterior border of the inner surface of the conch. Muzzle low, not especially broadened, with small, narrow noseleaf lacking lateral sup- plementary leaflets; anterior leaf narrow, rather elongate, its total width about two thirds of the width of the muzzle, widest at a point level with the nostrils, narrowed anteriorly with a small, rounded median emargination. Central part of internarial septum expanded into a small, rounded, lobular and thickened disc-like structure lying in the narial depression slightly anteriorly to the nostrils: laterally this disc is slightly swollen, with a shallow median trough separating its lateral lobes; anteriorly the margins of the expansion curve sharply inwards to join the anterior leaf by a short, constricted and unthickened internarial segment, posteriorly merging similarly but less abruptly with the base of the intermediate leaf. Narial lappets small but evident, the nostrils very slightly pocketed. Intermediate leaf sometimes with four small glands, not sharply demarcated from anterior leaf and not especially elevated or inflated. Posterior leaf high, slightly semicircular, its lower half or a little more divided by three broad, ill-defined septa into four shallow pockets, its upper part smooth; no serrated structure on its posterior face. A prominent frontal sac with horizontal aperture lies immediately behind the posterior leaf in male examples, represented in a female specimen by a small tuft of hair. All but one of the specimens available in London are in alcohol and have been so for some years: the sole dry example also appears to have been preserved in this way, possibly for a considerable period. The dorsal surface is now mid-brown, the hairs pale cream at the base and generously tipped with the brown terminal colour, which doubtless has been bleached to some extent by fluid preservation; the ventral surface is paler, largely lacking any brown, and has a greyish or greyish buff tinge. Skull very small (condylocanine length 12-7-13-1 mm) with inflated, elongate and rather narrow braincase, its length from occiput to narrowest part of postorbital constriction one fifth greater than its greatest width across the mastoids. Postorbital region strongly con- stricted, the rostrum narrow and uninflated, its greatest supraorbital width about two fifths of the mastoid width; anterior and lateral rostral compartments not much inflated, the anterior part of the rostrum in profile a little below rather than level with the junction of the sagittal and supraorbital crests, the upper profile of the rostrum sloping slightly down- ward anteriorly rather than horizontal, and curving smoothly rather than abruptly to the maxillae. Zygomata robust, with a low jugal eminence; anteorbital foramen elongate, closed by a narrow bar of bone. Premaxillae making a broadly V-shaped junction with the maxillae; palate long, narrow, the toothrows strongly convergent anteriorly; palation rounded, level anteriorly with a line joining the anterior faces of m 3 ~ 3 . Mesopterygoid fossa wide, the pterygoids slightly flared; sphenoidal bridge moderate, flanked by elongate apertures; basi- sphenoidal depression wide and shallow, subcircular in outline; basioccipital wide, the CHIROPTERA 79 cochleae widely separated. Tympanic bullae long, narrow, almost platelet-like, anteriorly approaching the rear of the glenoid fossa, in length considerably exceeding the antero- posterior diameter of the exposed part of the associated cochleae, while in width the tympanic bullae are equal to rather less than one half the diameter of the exposed part of the associated cochleae along the other axis; cochleae small, not much inflated, their greatest exposed width about one and three quarter times their distance apart, the exposed part more elliptical rather than subcircular in outline. Dentition with no unusual features; upper incisors weak, their tips convergent, the outer lobe obsolescent; anterior upper premolar (pm 2 ) small, compressed between the canine and the second upper premolar (pm 4 ) or very slightly extruded but nonetheless separating these teeth; posterior ridge of last upper molar one half of the length of its anterior ridge; outer lower incisors rather larger in crown area than inner lower incisors; anterior lower premolar (pm 2 ) about equal in length to second lower premolar (pm 4 ) and one half to three quarters its height. Measurements of the holotype, followed by minima and maxima of the series of six (except where indicated in parentheses) measured in London: length of forearm 37- 1 , 35- 1-38-2; con- dylocanine length 12-7, 12-7-13-1 (5); least interorbital width 2-0, 2-0-2-1; rostral width 3-6, 3-6-3-7; width across anteorbital foramina, 3-6, 3-5-3-7; zygomatic width 7-4, 7-2-7-4; width of braincase 6-9, 6-5-6-9 (5); mastoid width 7-8, 7-6-7-9, d-c 1 (alveoli) 3-1,3-0-3-3; m 3 -m 3 4-8, 4-8-4-9; width sphenoidal depression 2-7, 2-6-2-8 (5); width basioccipital 2-68, 2-62-2-77; c-m 3 4-8, 4-7^-8; length complete mandible from condyles 8-5, 8-2-8-6 (5); length right ramus from condyle 8-9, 8-9-9-2 (4); c-m 3 5-1, 5-0-5-2; length tympanic bulla 2-57, 2-49-2-72, width tympanic bulla 1-08, 0-98-1-13; antero-posterior diameter of cochlea 2-01, 1-80-2-03; transverse diameter of exposed part of cochlea 2-23, 2-21-2-33. ETYMOLOGY. The name of the new species is drawn from ataos, a disc, and 0uXA,ov, a leaf. REMARKS. The noseleaf of this new species is described (p. 165) and illustrated (fig. 61) by Lekagul & McNeely (1977) as Hipposideros cineraceus. The illustration of the skull (p. 166) of H. cineraceus provided by these authors is in fact of that species, having in contrast to the skull of H. halophyllus an inflated, higher rostrum, broad, short tympanic bullae and rounded rather than elongate cochleae. The material of//, halophyllus examined in London has come from the Thai National Reference Collection: all but one of these specimens was identified initially as H. cineraceus in Thailand, the exception being referred formerly to H. ater. Evidently Lekagul & McNeely employed a specimen labelled H. cineraceus from this collection as the basis of their description and illustration of the noseleaf. The new species is similar in size to Hipposideros cineraceus and a little smaller than //. ater, with either of which it can at first inspection be confused. Its ears are similar in size and shape to those of cineraceus but in this species there is a distinct fold or thickening at the antitragal lobe. There is also a slight thickening with a small antitragal fold in the ear of H. ater. The anterior leaf in H. halophyllus is shallowly but distinctly emarginated just above the centre of the upper lip: neither cineraceus nor ater display any such emargination and although in both of these the internarial septum is inflated and sometimes bulbous there is no evidence of the development of any disc-like structure between and slightly in advance of the nostrils, the septum remaining more or less parallel-sided although swollen. Cranially, halophyllus may be distinguished from cineraceus and ater by its less inflated anterior narial compartments and lower anterior rostrum which slopes more gently to the canines, by its narrower, longer tympanic bullae, its more elongate rather than subcircular cochleae, and by its broader basioccipital. DISCUSSION. Modification of the internarial septum into a circular or subcircular disc in Hipposideros occurs in the three African species H. curtus Allen, 1921, H.jonesi Hayman, 1947 and H. marisae Aellen, 1954, and also in one other Asian species, H. ridleyi Robinson & Kloss, 1911 from Malaya and Borneo. All belong to the bicolor group of Hipposideros and except for curtus are allocated by Hill (1963) to the bicolor subgroup, characterized by 80 J. E. HILL & S. YENBUTRA Fig. 1 . Hipposideros halophyllus. 9 TNRC 54-3704. Head x 5 Fig. 2 Hipposideros halophyllus. "' T 'This research was carried out in the Department of Zoology, British Museum (Natural History) and was submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy in the Faculty of Science, University of London. The author's present address: Department of Anatomy & Cell Biology, St Mary's Hospital Medical School, Norfolk Place, London W2 1PG. Bull. Br. Mus. not. Hist. (Zool.) 47(2): 83-150 Issued 26 July 1984 83 84 R. A. TRAVERS Vertebral column . 125 Dorsal and anal fin spines . . . . . . . . . 127 Caudal fin . .127 Squamation . 129 Myology .... 129 Cephalic muscles . ........ 129 Adductor mandibulae 129 Adductor arcus palatini 1 30 Other features . . . ... 130 Anterior nostril 1 30 II. Intrarelationships in the Mastacembeloidei 131 Proposed changes in classification 1 39 Diagnoses for the Synbranchiformes . 141 Synbranchiformes 141 Synbranchoidei 141 Mastacembeloidei 141 Chaudhuriidae 142 Mastacembelidae 143 Acknowledgements . 146 References 146 Synopsis The Mastacembeloidei or spiny eels (comprising the families Mastacembelidae, Chaudhuriidae and Pillaiidae) is a distinctive group of about 70 freshwater species with a tropical and subtropical Oriental and Ethiopian distribution, currently recognised as a suborder of the perciform fishes. The majority of its 70 species have been placed in a single genus, Mastacembelus, without regard to their genealogical relationships, and the suborder as a whole has never been the subject of a detailed taxonomic or anatomical review. A revision of the genera and families within the suborder, and a reconsideration of its interrelationships within the Percomorpha, are the overall objectives of this study. It is based on numerous anatomical characters drawn from the descriptions in Travers (1984) and involves a comparison of their condition with that of their homologues in other teleostean lineages. This analysis indicates that the mastacembeloids, long associated with the Perciformes, should be reallocated to the Synbranchiformes. A phylogenetic hypothesis of their intrarelationships is also proposed, viz., the Mastacembeloidei can be resolved into two lineages: the Chaudhuriidae (expanded to incorporate two genera) and the Mastacembelidae (divided into two subfamilies representing the Asian and African species). This hypothesis results in the elevation of the sole endemic Chinese species, Mastacembelus sinensis, to a monotypic genus within the Chaudhuriidae, and the generic synonymy ofPillaia (and Garo) with Chaudhuria (but the retention of both the latter taxa as subgenera ofChaud- hurid). The Asian mastacembelid subfamily, Mastacembelinae, retains the genera Mastacembelus and Macrognathus although the former is restricted to six species only, and the latter expanded to include eight species previously included in Mastacembelus. The African species are shown to be phyletically distinct and to warrant the creation of a new subfamily and new genera for two major African sub lineages. Introduction The Mastacembeloidei, or spiny-eels, are a group of freshwater teleost fishes occurring in the Oriental and Ethiopian zoogeographical regions. The Oriental species are widely distrib- uted in SE. Asia and extend from the eastern China seaboard, through the continental islands of Indonesia to the Middle East (Fig. 1). This pattern, together with their recent dis- covery in southern Iran (Coad, 1979), gives these fishes a continuous distribution throughout their Oriental range. The absence of mastacembeloids from the Arabian Peninsula, North Africa and the Horn of Africa, however, has resulted in the geographical isolation of the Oriental fauna from the Ethiopian species. These are restricted to tropical and subtropical MASTACEMBELOIDEI III PHYLOGENETIC 85 waters of Central Africa; embracing the Nilo-Sudan, Upper and Lower Guinea, Zaire, East Coast and Zambezi ichthyofaunal provinces of Roberts (1975). Mastacembeloids occur in a variety of freshwater habitats at high and low altitudes, and are common in riverine and lacustrine environments, streams and ponds (Job, 1941; Sufi, 1956; Matthes, 1962; Poll & Matthes, 1962; Skeleton, 1976). At least four African species are cavernicoles (Poll, 1953, 1958, 1959 & 1973 and Roberts & Stewart, 1976) and show considerable atrophy of the eye tissues, an associated hypertrophy of the superficial parts of the adductor mandibulae musculature and even lack of pigment (Poll, 1973). A group of Asian mastacembeloid taxa exhibit an elaborate burrow- ing mechanism (Job, 1941; Sufi, 1956); however, this habit is not found in all species (Schofield, 1962). Most mastacembeloids appear to be carnivores with a wide range of feeding strategies. Food organisms range from small zooplankton (Job, 1941; Sufi, 1956) through aquatic insect larvae and oligochaetes (Roberts, 1980) to other fishes (pers. obs.) including both eggs and fry (Hamid Khan, 1934) and even mastacembeloid species with a relatively small adult size (Staeck, 1976). To a large extent the prey species are related to the size and developmental stage of the predators. Reproduction in the mastacembeloids is poorly known. There are brief descriptions of the spawning activity in a single species in captivity (Schoenebeck, 1955; Polder, 1963; Franke, 1965), artificially induced spawning (Kochetov, 1982) and the periodic occurrence of vast numbers of juveniles in Lake Tanganyika (Brichard, 1978), but reproductive behaviour in nature has never been observed. Many mastacembeloids are thought to have some form of aerial respiration (Dobson, 1874; Day, 1877; Ghosh, 1933; Hora, 1935), although reports are contradictory and the presence of suprapharyngeal or swimbladder adaptations has never been shown. Whether survival in oxygen deficient waters is by some form of cutaneous respiration (Mittal & Datta Munshi, 1971), or by inanition with respiration at a standstill (Job, 1941), requires further research before an accurate assessment can be made. Fig. 1 Present-day distribution of mastacembeloid Oriental and Ethiopian species. 86 R. A. TRAVERS A pseudobranch, once thought to be absent in mastacembeloids (Day, 1889; Boulenger, 1915: 12) has recently been described in some Asian species (Bhargava, 1953). A spherical sac- like pseudobranch situated above the epithelium roofing the oral cavity was found in all taxa examined. This study is based on the many osteological and myological features shown (Travers, 1984) to be of potential value in reconstructing phylogenetic relationships. These morpho- logical characters will be analysed by comparing their condition with that of their homo- logues (Patterson, 19826) in other groups of percomorph fishes (acanthomorphs) or with the teleosts as a whole (see below). The objectives of these comparative studies, besides providing an analysis of mastacem- beloid interrelationships with other percomorph fishes, was an attempt to revise the intra- relationships of the group. Only by revealing the phylogeny of these fishes can an improved understanding of their biogeographical history be gained (Greenwood, 1983). Although numerous specific features were identified (see Travers, 1984), and are included where possible in the analysis, a formal species level revision was not attempted. Materials and methods Materials The bulk of the comparative outgroup material examined is tabulated in Travers (1981). In addition to these specimens further taxa are listed in systematic order in Table 1; all are given with their register number and codes indicating the type of examination or preparation involved. Unless otherwise indicated, all are BM(NH) registered specimens. For a complete list of the mastacembeloid specimens upon which this study is based, for nomenclatural references and the techniques of morphological analysis, see Travers, 1984. Methods The inter- and intrarelationships of the mastacembeloids were evaluated by the application of a cladistic methodology as originally defined by Hennig, 1950 & 1979 and advocated latterly by Eldredge & Cracraft, 1980, Nelson & Platnick, 1981, and Wiley, 1981. This methodology has, over the last decade, brought increased order to the complexities of teleostean classification regardless of the vociferous debate (e.g. see Nature Correspondence from volume 275 to 292), and the proliferation of conceptual literature (e.g. see Systematic Zoology from 1967 (4): 289-292, to date), that it has engendered. To determine the primitive (plesiomorphic) or derived (apomorphic) nature of mastacem- beloid characters, in the absence of a complete ontogenetic history of all species, a series of outgroup comparisons was made in a manner similar to that discussed by Watrous & Wheeler (1981); see Farris (1982) for a critical review of their study. Information from onto- genetic transformations (de Beer, 1958; Gould, 1977; Nelson, 1978; Rosen, 1982), where available was utilized especially if comparisons could be made with similar developmental stages in outgroup taxa (Fink, 1982; Patterson, 1983). Only those uniquely derived features confined to individuals of a single species were identified as autapomorphic characters. When detected in this restricted sense these char- acters can be used to identify species, regardless of whether or not they are strictly definable (Patterson, 1982a). Where an outgroup has been the subject of a recent study, highly derived species were excluded so as not to be mislead by taxa that are unrepresentative for their group as a whole. In poorly studied assemblages a wide range of representatives was examined in order to avoid overlooking a group which may be masked by a previous incorrect assessment of its characters and hence given an erroneous taxonomic allocation. Outgroup taxa were taken from all major percomorph assemblages. Emphasis was given to perciform lineages, since these represent the largest acanthopterygian groups, and several beryciform -families since the perciforms are generally thought to have been derived from MASTACEMBELOIDEI IK PHYLOGENETIC 87 a beryciform species (Patterson 1964; Greenwood et al, 1966; McAllister, 1968; Zehren, 1979). However, these beryciform taxa are ill-defined and thought by most authors to rep- resent polyphyletic assemblages (Patterson, 1964; Greenwood et al, 1966; Rosen, 1973; Zehren, 1979). Furthermore, the task of analysing such groups is complicated by the large number of taxa involved and also, as Rosen (1973:398) observed, by: '...the lack of co-ordinated comprehensive studies of character complexes throughout the group'. For example, the only synapomorphy so far proposed for the Perciformes is the presence of an interarcual cartilage (Rosen & Greenwood, 1976) and even this has been shown recently to have a far wider occurrence than had been previously thought (Travers, 1981; it may even occur in some ophichthid eels (McCosker, 1977 and M. Leiby pers. comm.). Table 1 Teleostean outgroup taxa (supplementary to those listed in Travers 1981). Species Reg. No. Preparation Arapaima gigas Elops hawaiensis Flops machnata Halosaurus owenii Notacanthus bonapartei Notacanthus sexspinis Anguilla anguilla Etrumeus teres Ostichthys parvidens Holocentrus rufus Zeusfaber Hypoptychus dybowskii Macrotrema caligans Macrotrema caligans Monopterus cuchia Synbranchus bengalensis Synbranchus javanicus Synbranchus marmoratus Mugil cephalus Pholis gunnellus Pholidichthys leucotaenia Pholidichthys leucotaenia Pholidichthys leucotaenia Scytalina cerdale Notograptus guttatus Ptilichthys goodei Stichaeus (Leptoblennius) mackayi Unreg. 1962.4.3: 1-25 1962.8.28: 1-7 1890.6.16: 55 1972.1.26:33-39 1873.12.13:27 1962.6.5: 2-4 1923.2.26: 73-78 1974.5.25: 747-753 1976.7.14: 79-81 1971.7.21: 86-90 1979.11.26: 1-3 1860.3. 19: 943 Type 1908.7.13: 1 Unreg. 1860.3.19: 1477 1862.11.1: 138 1981.1.15: 1117-1119 1913.7.10: 31-34 1981.2.20:446-479 1974.3.14: 1 USNM 206237 USNM Gift USNM 70801 USNM Gift USNM 130266 1896.7.23: 183 DS A A AP MD DS MD A MD MD MD MD AP AP DS MD MD MD MD MD MD A AP AP A/A AP MD Abbreviations Anatomical Aa Anguloarticular Add Mand Adductor mandibulae Asph Autosphenotic Bbl 1-3 Basibranchial 1-3 Bbl KC Basibranchial I keel cartilaginous Bh Basihyal Bh+ Bbl Basihyal fused with basibranchial I BR Branchiostegal rays Bs Basisphenoid C Cleithrum 88 R. A. TRAVERS Com Coronomeckelian DO Dilatator operculi Dsph Dermosphenotic Ect Ectopterygoid End Endopterygoid F Frontal Fa Fimbria FDL Frontal descending lamina FFac Frontal facet Fu Fimbrule Hb 2-3 Hyobranchial 2-3 Hb3 AP Hyobranchial 3 anterior process Hyo Hyomandibula Hyo Add Hyohyoidei adductores HyoMF Hyomandibula metapterygoid flange Hyo SP Hyomandibula symplectic process lop Interoperculum LE Lateral ethmoid LE xsc Lateral extrascapula Lig Ligament LO Levator operculi MC Meckel's cartilage Met Metapterygoid MExsc Medial extrascapula MP Maxillary process Op Operculum P Parasphenoid Pal Palatine Palopt Palatopterygoid PalT Palatine teeth PAW Parasphenoid ascending 'wing' Pop Preoperculum Pr Prootic PrAP Prootic anterior process Pt Pterosphenoid Ptm Posttemporal PtmT Posttemporal tubule Q Quadrate Ra Retroarticular Sc Supracleithrum Sen Pap Sensory papillae Sep Septum (ossified) Sop Suboperculum Sph Sphenotic Sym Symplectic Uh Urohyal UhAP Urohyal ascending process Note on the figures: even stipple-dots indicate the presence of cartilage. The scale on all figures indicates 1 mm. Table of study material A/A A DS MD AP Unreg. Institutional BM(NH) USNM Double stained transparency (alizarin red and alcian blue) Alizarin stained transparency Dry skeleton preparation Muscle dissection (cheek & opercular region) Alcohol preserved specimen not available for dissection or preparation Unregistered specimen held at BM(NH) British Museum (Natural History). United States National Museum, Washington. MASTACEMBELOIDEI IK PHYLOGENETIC 89 Mastacembeloid interrelationships I. Character analyses Osteology NEUROCRANIUM The neurocranium exhibits the general trends (mainly reductional) and particular features that are currently recognised as diagnostic for acanthopterygian fishes (see Zehren, 1979: 163-166 for a recent summary), although they are somewhat masked by the extreme precommissural attentuation of the skull. Of the eleven acanthopterygian neurocranial and circumorbital character states listed by Patterson (1964: 449) and Zehren (op. cit.) eight are readily recognisable in almost all mastacembeloids. A further derived feature found by Patterson (1975: 568) only in the Acanthopterygii is the pons moultoni, a loop of bone on the inner face of the sphenotic which surrounds the anterior semi-circular canal. The medial face of the sphenotic in mastacembeloids houses the anterior semi-circular canal in such a structure and thus conforms to the condition in the Acanthopterygii. Surprisingly, Zehren (1979) did not mention the pons moultoni in his study of the Beryciformes. Elongation of the supraethmoid and vomer in mastacembeloids contributes to the gener- ally pointed snout in these fishes, although the lateral ethmoids are of more usual proportions (Travers, 1984). In other percomorphs with elongate syncrania, including such forms as the congrogadids, pholidichthyids, sphyraenids, acanthurids, luciocephalids and synbranchids, the ethmovomerine region is not always attenuated. In Congrogadus subduceus and Pholidichthys leucotaenia this region is of similar proportions to that found in most other percomorphs, any elongation being restricted to the postorbital neurocranial bones. In Sphyraena obtusata, Acanthurus bahianus and Luciocephalus pulcher the ethmovomerine region is particularly elongated, whilst the braincase proportions are similar to those in most percomorph fishes. This condition is produced in Sphyraena by elongation of the lateral ethmoids, whilst in Luciocephalus the prevomer and nasals are particularly lengthened (Liem, 1967). The anterior region of the parasphenoid is particularly long in Acanthurus and, combined with the long supraethmoid, it contributes to the elongate ethmovomerine region. The vomer in synbranchids was described by Rosen & Greenwood (1976: 49) as a 'long, thin strut' elongated to a point below the pterosphenoids and basisphenoid. This is the only outgroup examined which has a vomerine shaft comparable in length to that in the mastacembeloids (e.g. compare the vomerine length in Rosen & Greenwood, 1976, figs. 57 & 59 with the vomer in other percomorphs). This may well be a synapomorphy of these taxa. Although an elongate ethmovomerine region occurs in a variety of what appear to be phyletically distant percomorph fishes, the method by which elongation is achieved in the mastacembeloids (by extreme lengthening of the vomer and supraethmoid) is not found in any other group (apart from a similar elongation of the vomer in the synbranchids). The sensory canal bearing bones of the ethmovomerine region (i.e. the nasal and 1st infraorbital) are also elongated, and the nasal has a particularly broad dorsal surface in mastacembeloids. The 1st infraorbital is long and tapered in a variety of percomorphs, including the synbranchids, ammodytids and luciocephalids. However, the nasal in these taxa is barely broader than the sensory canal it carries. The concomitant elongation in the mastacembeloids of the supraethmoid, vomer and 1st infraorbital bone, accompanied by a long nasal with a broad dorsal surface, results in a snout unlike that found in any of the other taxa examined. It is thus considered to be a synapomorphy for the group. The mastacembeloid lateral ethmoid is not elongate although the 'ethmoids' (presumably including the lateral ethmoid) were included by Rosen & Greenwood (1976) in their list of 90 R. A. TRAVERS 'greatly attentuated' mastacembeloid neurocranial elements. In fact the lateral ethmoids retain the general percomorph proportions, but are fused in the midline and have an overall tubular shape. In percomorph fishes the lateral ethmoids are generally plate-like bones lying on either side of the supraethmoid and are separated from each other medially by the cartilaginous, posteroventral end (septal cartilage) of the supraethmoid. Medial fusion of the lateral ethmoids in mastacembeloids, dorsal to the cartilaginous pos- terior end of the supraethmoid is an arrangement found also in blennioids, (e.g. Notograptus guttatus) and in gobioids (e.g. Trypauchen wakae). However, the tubular shape of the lateral ethmoids was not found in any other outgroup taxa. The mastacembeloid pterosphenoids have wide lateral faces and are connected ventro- medially (Travers, 1984: 51). Among the outgroups examined (see Table 1) medial pterosphenoid connections were found only in the clupeid Etrumeus, some beryciforms (e.g. Diretmus argenteus and Ostichthys trachypoma; Zehren, 1979) and the anabantoids (e.g. Belontia and Trichogaster leeri; Liem, 1963). In the anabantoids the pterosphenoids are not connected ventrally, but dorsally are linked by long wing- like processes, running transversely across the orbital cavity. In two beryciform families (Diretmidae and Holocentridae) Zehren (1979: 232) found the pterosphenoids to have their ' . . . anterior lower edges meet in the midline closing off the optic fenestra' and, on the basis of outgroup comparisons concluded that this arrangement represented the apomorphic condition (see below). In synbranchids the massive development of the pterosphenoids has been noted by Rosen & Greenwood (1976: 44) who found that, with the basisphenoid, these bones occupy ' . . . somewhat less than half the total length of the neurocranium'. Although the ptero- sphenoid is large in synbranchids it does not contact its partner in the midline. Rosen & Greenwood (1976) also listed the bones involved in the neurocranial lengthening of mastacembeloids, when comparing them with synbranchids, but failed to mention the central role of the pterosphenoids. The wide lateral face of the pterosphenoids and their medial union ventrally (resulting in the ventral half of the optic foramen being bounded by them) is a synapomorphic character of all the mastacembeloids (its absence in Pillaia and Mastacembelus aviceps is discussed on p. 1 10). In the beryciforms in which the pterosphenoids are connected in the midline (discussed above), these bones lack wide lateral faces and their medial connection is thought to be convergent with that in the mastacembeloids. The basisphenoid is a characteristically small, compressed bone in mastacembeloids (Travers 1984: 53). This configuration appears to be directly associated with the median pterosphenoid connection, and represents a derived state of the large Y-shaped bone present in most teleostean lineages. It can be noted that in beryciforms and Etrumeus, taxa also with medially fused pterosphenoids, the basisphenoid retains its plesiomorphic condition. A preorbital (or, more correctly, suborbital) spine that pierces the skin is a characteristic feature of almost all mastacembeloids (Travers, 1984). A preorbital spine is also present in halosauroids (sensu Greenwood, 1977) as described by McDowell (1973) and illustrated by Greenwood (op. cit. figs. 5, 7, 9, 10 & 14), and in some Ostariophysii (e.g. Cobitidae). However, in these fishes it is produced, respectively, from the maxilla or the lateral ethmoid, and is not homologous with the mastacembeloid preorbital spine. Here the spine is the posterior end of the large first infraorbital bone. In no other teleostean taxon is the first infraorbital developed in this way, and the presence of the spine is a further valuable synapomorphy of the mastacembeloids. A long prootic, characterised by a distinct anterior process passing across the anterolateral face of the neurocranium and into the orbital cavity, is typical of most mastacembeloid taxa (Travers, 1984: 58). This is contrary to the opinion expressed by Springer & Freihofer (1976: 37) that, 'In the highly specialised Mastacembelidae and Chaudhuriidae the parasphenoid also lacks an MASTACEMBELOIDEI II: PHYLOGENETIC 91 ascending process but either the prootic is entirely blocked by the pterosphenoid- pleurosphenoid bones from entering the postorbital margin or the pterosphenoid- pleurosphenoid bones are absent (D. E. Rosen, pers. comm.)'. The plesiomorph condition of the teleostean prootic is one in which the anterolateral edge contributes to the posterior rim of the orbit. In a few, and diverse, taxa the anterior margin of the prootic is prevented from bordering the orbit by the ascending parasphenoid process, the pterosphenoid and/or the descending lamina of the frontal. This occurs particularly in taxa with elongate neurocrania, and is seen in some Lates species illustrated by Greenwood (1976: fig. 3). FDL Dsph PrAP Fig. 2 Congrogadus subduceus, otic region of neurocranium; lateral view, left side. A massive pterosphenoid and basisphenoid prevent the anterolateral extension of the prootic from entering the border of the small orbital cavity in the synbranchids (Rosen & Greenwood, 1976). In the Pholidichthyidae (Springer & Freihofer, 1976) the neurocranium is elongate and the prootic, lengthened anteriorly, has a wide lateral face, (Fig. 4a). The anterior region of the prootic in this taxon passess above the lateral face of the basisphenoid, and its anterior edge borders the posterior rim of the orbit. A very large prootic is also present in the congrogadids (e.g. Congrogadus subduceus, Fig. 2), and is distinguished by its long anterior region (between the ventral edge of the pterosphenoid and upper margin of the parasphenoid) which passes from the trigeminofacialis chamber to a point posterior to the rim of the orbit. Thus, the large size of the prootic in mastacembeloids is not in itself exceptional. Rather, the exceptional feature is the anterior region of the prootic overlying the ventrolateral face of the pterosphenoid and being developed into a long anterior process extending into the orbital cavity. This constitutes a major synapomorphic feature of the mastacembeloid neurocranium. The trigeminofacialis chamber lies in the prootic; its development has been discussed by Patterson (1964: 434-438). He concludes that the plesiomorphic condition for teleosts (as seen for example in Flops) was one in which the truncus hyomandibularis, the jugular vein and the orbital artery are separated by individual foramina in the pars jugularis. This condition differs from that in perciforms where the three foramina are confluent. The progressive reduction from four to two external openings in the pars jugularis among beryciform fishes has recently been demonstrated by Zehren (1979: 235) and lends support to Patterson's hypothesis (op. cit.) that ' . . . during the evolution of teleosts there has been a simplification of the pars jugularis'. 92 R. A. TRAVERS A large trigeminal foramen (generally situated anterior to the lateral commissure) and a small facial foramen (generally medial to the lateral commissure) are the only foramina in the pars jugularis of mastacembeloids, which are apomorphic in this respect. The mastacembeloid otic bulla is a small recess in the posteromedial face of the prootic, and completely houses the sacculus in most taxa. Only these fishes among the teleosts, have their saccular recess contained entirely within the prootic. In all others the recess is formed from the prootic, exoccipital and basioccipital. The relative contribution of these three bones does, however, vary from an almost equal contribution to one in which the greater part is derived from the prootic (e.g. congrogadids, tripterygiids of the genus Paraclinus, and Channa obscurd). This housing of the otolith bulla in the prootic only is a synapomorphic character of the mastacembeloids. Precommissural elongation of the neurocranial bones in mastacembeloids involves that region of the autosphenotic lying anterodorsal to the lateral commissure (T ravers, 1984: 69). This part of the sphenotic is produced into a wide anterolateral flange that generally extends across part of the lateral face of the pterosphenoid and descending frontal lamina, but does not enter the posterior border of the orbit. The postorbital process on the sphenotic, as a a FDL Asph FDL PAW Fig. 3 Neurocranium of (a) Ophidian rochei, and (b) Lycodes brevipes. Left side of otic region, lateral aspect. MASTACEMBELOIDEI III PHYLOGENETIC 93 result of its anterolateral flange, has a posterior position relative to that of a similar process in other perciform fishes, for example the labroids (Rognes, 1973) and cichlids (Stiassny, 1981). This posterior position of the postorbital process indicates the extent to which the mastacembeloid sphenotic has expanded anteriorly. In its plesiomorphic state the teleostean autosphenotic forms the posterodorsal corner of the orbit, a condition found in almost all major teleostean lineages, including many beryciform and perciform fishes. Some development of the autosphenotic occurs in several phylogenetically distant acanthomorph lineages (e.g. Ophidian rochei, Fig. 3a; Pholidichthys leucotaenia and Xiphistes mucosus, Fig. 4a & b; Ammodytes tobianus, Fig. 4c), although in none is it developed to an extent comparable with that in the mastacembeloids, and in all the bone, unlike that in mastacembeloids, still forms the posterodorsal margin of the orbit. The ammodytoids, (e.g. Ammodytes tobianus, Fig. 4c) are the only other perciform group found to have a sphenotic with a wide anterolateral face. However, in these taxa the sphenotic forms the posterodorsal margin of the orbit and in this respect it retains the plesiomorph condition. Thus, the condition of the wide anterolateral flange on the sphenotic in mastacembeloids which falls short of the postorbital margin, is a synapomorphy of the group. The mastacembeloids lack a posttemporal fossa (T ravers, 1984: 17). It is a common feature of lower teleosts and apart from having lost its bony roof, is widespread among higher euteleosts. In these fishes the posttemporal fossa generally lies lateral to the supratemporal fossa (Patterson, 1964: 449 & 1975: 392-5). Such fossae are typically found in the perciform neurocranium. The lack of a posttemporal fossa must, by virtue of the widescale presence of this fossa in teleosts, be a secondary loss and as such may be considered an apomorphic feature of these fishes. It is not, however, a feature restricted to these fishes. The fossa appears to have been lost independently in the following acanthomorph lineages: ophidioids (e.g. Campus acus), synbranchoids (e.g. Synbranchus marmoratus\ blennioids (e.g. Notograptus guttatus), trachinoids (e.g. Trachinus viperd) callionymoids (e.g. Callionymus lyrd), acanthuroids (e.g. Acanthurus bahrianus) and channoids (e.g. Channa obscurd). A wide subtemporal recess in the posterolateral wall of the neurocranium, defined in part by the prootic, pterotic and exoccipital, is characteristic of all mastacembeloids (T ravers, 1984) and is the site of origin for the levator musculature of the branchial arches. This recess, which is little more than a shallow lateral concavity, is not thought to be the homologue of the subtemporal fossa in lower teleosts (Forey, 1973; Patterson, 1975). The occipital condyle in all mastacembeloid taxa is in the form of a tripartite, concave socket (Travers, 1984: 71) formed from equal contributions by the exoccipitals and the basioccipital. The hemispherical anterior face of the first centrum articulates in this socket. A tripartite occipital condyle occurs in the majority of teleosts including the more basal assemblages (Forey, 1973: 12-19; Patterson, 1975: 318). Among these fishes the tripartite basi- and exoccipital facets are arranged in a variety of ways. Rosen & Patterson (1969) recognised two general apomorphic conditions of the condyle in acanthomorph lineages. The paracanthopterygians they examined have the exoccipital facets displaced laterally, losing contact with the basioccipital facet, whereas, in the acan- thopterygians they examined the exoccipital facets were displaced dorsally. Thus, the masta- cembeloid arrangement in which the basi- and exoccipital facets are firmly joined into a single tripartite, concave socket is considered to represent an even more derived condition. However, this arrangement is not unique to mastacembeloids as the facets are also developed into a single concave socket in myctophids, polymixids and ammodytoids. In, for example, Myctophum punctatum (illustrated by Rosen & Patterson, 1969: fig. 6 ID) the anterior face of the first centrum is tightly fused with the occipital socket and cranial movement must be considerably restricted. The tripartite occipital socket in Polymixia japonica, a species recently interpreted by Zehren (1979) as a basal percomorph, was also illustrated by Rosen & Patterson (1969: fig. 6 IE). In this taxon the anterior face of the first centrum has expanded into a convex condyle that fits into the occipital socket. This convexity of the first centrum may be the result of 94 R. A. TRAVERS FDL Pt Asph Asph Pt FDL / Bs RAW PrAP Fig. 4 Lateral view of neurocranial otic region in; (a) Pholidichthys leucotaenia, left side; (b) Xiphistes mucosus, right side; (c) Ammodytes tobianus, left side. the osteoid cone (Patterson, 1975) having fused with it and the anterior part of the cone becomes rounded to fit into the occipital facet. This apomorphic development of the anterior face of the first centrum has been taken a stage further in mastacembeloids. Here the anterior face is produced into a hemispherical condyle, that functionally forms a 'ball and socket' joint between the vertebral column and neurocranium. This is a synapomorphy of all mastacembeloids and is important evidence in support of the monophyletic origin of the group (see p. 1 08). In no other acanthopterygians, apart from the ammodytoids (Gosline, 1963), is there a 'ball and socket' joint between the MASTACEMBELOIDEI II: PHYLOGENETIC 95 vertebral column and neurocranium. Although the arrangement of the joint in ammodytoids is of a similarly derived type, in the absence of any further derived characters shared by these fishes it is thought that the resemblance is homoplastic. The absence of a posttemporal bone was first noted by Regan (1912) in Mastacembelus armatus and is confirmed by all mastacembeloid taxa I have examined. In place of the posttemporal, 1-3 ossified tubules occur in most species. Among teleosts, the only other groups lacking a posttemporal bone are the anguilloids, for example Anguilla anguilla, the notacanthids (McDowell, 1973: 137) and some siluroids (G. Howes, pers. comm.). MExsc Ptm LExsc Sc MExsc Ptm LExsc PtT Sc Ptm Sc Fig. 5 Articulation of the left posttemporal bone to the pectoral girdle in: (a) Zoarces viviparus; (b) Lycodes brevipes; (c) Dadyanos insignis. Viewed obliquely from a dorsolateral position. 96 R. A. TRAVERS Sc Ptm Fig. 6 Articulation of the left posttemporal bone in: (a) Monopterus albus; (b) Synbranchm marmoratus. Lateral view of the elements which are depicted in situ. In the true eels the pectoral girdle lies posterior to the cranium, adjacent to the 7th or 8th abdominal vertebrae. The postcranial sensory canal in Anguilla passes through three small dermal tubules lying between the cranium and pectoral girdle. Zoarcoids, for example Zoarces viviparus, Lycodes brevipes and Dadyanos insignis (Fig. 5), are also distinguished by their eel-like shape and posteriorly displaced pectoral girdle. This is connected to the neurocranium (epioccipital) by a narrow, blade- like posttemporal bone, through which the postcranial sensory canal does not run; instead it passess laterally, parallel to the posttemporal and is housed in two ossified dermal tubules. From the condition in zoarcids it seems reasonable to conclude that the ossified post- cranial tubules in mastacembeloids and some anguilloids are not necessarily remnants of the posttemporal. The absence of a posttemporal distinguishes mastacembeloids from all other neoteleosts. Its loss, like that in some anguilloids (discussed above) and notacanthids (McDowell, 1973), is correlated with the posterior position of the pectoral girdle, (see Travers, 1984: 73). The synbranchids also come into the category of eel-like neoteleostean fish with a reduced, posteriorly displaced pectoral girdle. A well-developed, forked, posttemporal connecting the basicranium to the pectoral girdle (generally adjacent to the 3rd & 4th abdominal vertebrae) occurs in Monopterus albus (Fig. 6a) and Ophisternon (Rosen & Greenwood, 1976: 63). On the other hand, in Synbranchus (e.g. S. marmoratus, Fig. 6b) the posttemporal is reduced to a narrow blade-like bone that tapers posteriorly from the basicranium (to which its MASTACEMBELOIDEI II: PHYLOGENETIC 97 anterior end is attached) and is not in contact with the pectoral girdle. The tendency in synbranchids towards reduction in size of the posttemporal is probably related to the position of the pectoral girdle. In its most derived condition (e.g. 5". marmoratus) the posttemporal has lost its connection to the supracleithrum, an arrangment which, although unique to the synbranchids, could represent an early stage in the transformation of this bone to its con- dition in the mastacembeloids (i.e. complete loss). Unfortunately, suitable material of the most plesiomorph synbranchid Macrotrema elegans was not available for study. Extrascapular bones are absent in all mastacembeloid taxa, (with the exception of Mastacembelus brachyrhinus, discussed below). The supratemporal arm of the cephalic sensory canal is completely enclosed in a transverse tube that passes across the parietal (T ravers, 1984: 72). This canal surfaces at the medial edge of the parietal, and crosses the supraoccipital as an open channel, joining its partner in the midline. The position of the supratemporal arm of the cephalic sensory canal in mastacembeloids may be the result of the lateral and medial extrascapulars (which generally house the canal) fusing along the posterodorsal surface of the parietal, or because true parietals have been replaced by extrascapulars (McDowell, 1973: 25). Alternatively, the extrascapulars may have been lost and the supratemporal sensory canal enclosed by the parietals during ontogeny. In all mastacembeloids the parietal has a posterolateral flange (Travers, 1984: 72) that lies along the dorsal junction of the pterotic and epioccipital, and encloses the most lateral region of the supratemporal sensory canal. The expansion of the parietal in this region suggests that the extrascapulars may have fused with its posterodorsal surface, presumably in a manner similar to that described by Patterson (1977: 98) for the fusion between the median extrascapula and the supraoccipital in primitive clupeomorphs. Furthermore, in Mastacem- belus paucispinis (Travers, 1984: fig 35a & c) a short, independent tubule, reminiscent of the posterior tubule-like region of the lateral extrascapula in other perciforms (e.g. Perca fluviatilis), is fused to the parietal between the pterotic and epioccipital. In my specimen of Mastacembelus brachyrhinus (uniquely among mastacembeloids) there is an independent lateral extrascapula on the dorsal surface of the parietal (albeit on the left side only, Travers, 1984: fig37a&c). The lateral and medial extrascapulae in higher euteleosts are short tubules which house the supratemporal arm of the cephalic sensory canal system as it traverses the dorsal surface of the neurocranium. Extrascapulae of this type are of widespread occurrence in the gadi- form, batrachiodiform, cyprinodontiform, beryciform, scorpaeniform and perciform assem- blages. In some of these the lateral and medial extrascapulae may be fused to the underlying parietal (dorsal surface), as seen for example, in the zoarcoids (e.g. Zoarces viviparus & Lycodes muraend) and some blennioids (e.g. Malacoctenus delalandei, Haliophus guttatus, Acanthemblemaria maria & Congrogadus subduceus). In all these examples the extra- scapulae, although fused to the parietal, are clearly distinguishable, retaining their overall shape and size. However, in other blennioids including members of the Blenniidae (Springer, 1968) and Stichaeoidea (Makushok, 1958: his Stichaeoidae), extrascapulae are absent and the supratemporal sensory canal lies within the parietal. This arrangement of the supra- temporal sensory canal, apart from the mastacembeloids, is found only in these blennioids among the teleosts examined. In some percomorphs, however, the extrascapulae and the supratemporal arm of the sensory canal are both absent, for example in the gobioids and synbranchoids, as well as in Chaudhuria and Pillaia among the mastacembeloids (see below). Thus, the total absence of discrete extrascapulae in mastacembeloids is a derived feature shared only with some blennioids. The lack of a supratemporal commissural sensory canal in Chaudhuria and Pillaia, taxa in which there appears to be a progressive reduction in the extent of the cephalic sensory canal system (see p. 1 13), may well be a further stage in such a trend (one convergent with that in the gobioids and synbranchoids). JAWS The upper jaw in mastacembeloids is non-protrusile and in this respect is rather exceptional 98 R. A. TRAVERS among percomorphs; indeed, jaw protrusibility is a characteristic feature of most neoteleosts (Liem & Lauder, 1983). Among percomorph fishes, relatively long premaxillary ascending processes and maxillary cranial condyles are absent only in the synbranchids and the mastacembeloids. The simple non-protrusile jaws in these taxa are similar to the plesiomorph teleostean condition seen in the osteoglossomorph, elopiform, clupeomorph and protacanthopterygian assemblages. Although the non-protrusile jaws in mastacembeloids and synbranchids appear to be of this type they have presumably been secondarily redeveloped from protrusile jaws (see Gosline, 1983: 324, discussed below p. 109 & 129). The mastacembeloid dentary has a posteroventral extension (Travers, 1984: 80) which tapers posteriorly. This process extends from the rim of the posterior sensory canal opening and lies along the ventral edge of the anguloarticular. In representatives from nearly all major teleostean lineages (particularly neoteleosts) the posterior opening of the sensory canal in the dentary marks the posteroventral tip of this bone; e.g. in Osteoglossum (Kershaw, 1976); Elops (Forey, 1973); Anguilla; Denticeps (Greenwood, 1968); Cyprinus; Salmo; Maurolicus; Chlorophthalmus; Myctophum; Percopsis; Gadus; Ophidian; Holocentrus and Serranus. In the numerous lower jaws taken from a wide selection of basal teleosts and illustrated by Nelson (1973), only that in Arapaima gigas (Nelson, 1973: fig. 2c & d) shows a process comparable with that in mastacembeloids, and must be considered a homoplasy. The dentary of Arapaima gigas illustrated in lateral view by Kershaw (1976: fig. 20, redrawn after Ridewood 1905) shows no posteroventral extension beyond the posterior opening of the sensory canal (the latter being clearly indicated); however, I have examined a skeletal preparation of Arapaima gigas and the long posteroventral process is clearly present. Of the remaining lower jaws illustrated by Nelson there is a posteroventral extension of the dentary beyond the posterior sensory canal pore (albeit to a lesser extent than in the mastacembeloids) in some engraulids e.g. Coilia mystus and Thrissina baelama (Nelson, 1973: fig. 5C, D&E, F). Both these taxa are characterised by a long, pointed mandible, and the short posterior projection on the dentary may be regarded as homoplastic with that in mastacembeloids and Arapaima. Among euteleosts, the synbranchids are the only group (apart from the mastacembeloids) in which there is a long posteroventral process on the dentary (illustrated by Rosen & Greenwood, 1976: fig. 60 & 61). This process extends beyond the posterior sensory canal opening along almost the entire ventral edge of the anguloarticular. Thus, it seems reasonable to conclude that the posterior extension of the dentary is a synapomorphy uniquely shared by mastacembeloids and synbranchids among euteleostean fishes. The mastacembeloid mandible is also exceptional in the size and position of its coronomeckelian, a large bone (relative to the other mandibular elements) lying across the anterolateral face of the suspensorium. A small coronomeckelian on the medial face of the anguloarticular is of common occurrence throughout the teleostomes (Starks, 1916), and this is taken to represent the plesiomorph condition both with regard to its size and position. The coronomeckelian was shown by Starks (1916) to be the ossified anterior end of the A 3 tendon. In support of this view he cited the condition of these elements in Spheroides annulatus ' . . . where the adductor tendon has obviously ossified for a short space leaving an interval of tendon between the ossified portion and the mandible'. This interpretation can also be applied to the arrangement of the coronomeckelian in mastacembeloids, except that in these fishes the tendon has ossified dorsal to the mandible. Tendons may become ossified (forming a sesamoid bone) in regions where tendon movement produces opposing frictional forces, for example where the tendon runs across a bony prominence. The long A 3 tendon in mastacembeloids runs across such a prominence the deep and somewhat bulbous anterolateral face of the ectopterygoid (Travers, 1984: fig. 5). The development of the unusually large, dorsally situated coronomeckelian in mastacem- beloids thus appears to be directly related to the shape of the ectopterygoid. The size and MASTACEMBELOIDEI III PHYLOGENETIC 99 position of the coronomeckelian in Chaudhuria and Pillaia (discussed below), taxa which lack an ectopterygoid with a deep anterolateral face, is evidence in support of this view. Although there is extensive variation in the size and shape of the coronomeckelian among teleosts, (see Fig. 7 a-g) in no other taxon is it comparable with that in mastacembeloids, for which it is taken to be a unique synapomorphy. The dorsal edge of the anguloarticular is straight in most mastacembeloids (Travers, 1984: 82) and lacks a coronoid process in all taxa except Macrognathus, where the coronoid elevation is low and broad based (see Travers, 1984: 80). The anguloarticular lacks a coronoid process in about half the synbranchid species recognised by Rosen & Greenwood (1976: 45), and this characteristic was considered to be of some phylogenetic interest by these authors. They were of the opinion that, 'Such coronoid prominences on the articular of teleosts are common, although in many unrelated fishes with elongate crania and jaws the process is absent'. The absence of a coronoid process on the anguloarticular in synbranchoids was thought by Rosen & Greenwood (1976) to be a plesiomorph feature of the taxon, and the processes present in Monopterus albus and Ophisternon species were thought to be independently gained autapomorphies. A coronoid process is absent on the anguloarticular in a variety of teleosts including the anguilloids (e.g. Anguilla anguilla}, some percoids (e.g. Scarus croicensis), blennioids (e.g. Notograptus guttatus and Pholidichthys leucotaenia [very low projection]), many gobioids (e.g. Gobius niger; Aphia minuta; Amblyopus brousonetti and Crystallogobius linearis), and notothenioids (e.g. Notothenia sema [very low projection]). These observations support the view held by Rosen & Greenwood (op. cit.) that many unrelated fishes lack a coronoid process and that its absence in percomorph lineages is plesiomorphic. PTERYGO-PALATINE ARCH Regan (1912) found that in mastacembeloids the ' . . . pterygoid is movably articulated with the lateral ethmoids external to the palatine', and noted that they are 'very perculiar' in these fishes. The ectopterygoids are large bones characterised by a deep anterolateral face and their direct connection to the lateral ethmoids (Travers, 1984: 83). This direct articulation of the large ectopterygoid (functionally replacing the palatine which lacks articulatory facets; see below) is the sole means by which the anterior end of the suspensorium is joined to the neurocranium in most mastacembeloid taxa. The articulation of the suspensorium to the neurocranium in almost all other euteleosts involves the palatine. Among lower teleosts, the palatine also plays a central role in suspensorial articulation with the neurocranium, although this does not necessarily exclude the ectopterygoid from having an articulatory function in some taxa, as for example in the osteoglossoids. In Osteoglossum there is only a single element in place of the ectopterygoid and palatine, which are, in the opinion of Kershaw (1976: 192), 'indistinguishably connected'. The anterior end of the 'ecto- palatine' bone is ligamentously connected to the lateral ethmoid in Osteoglossum. The ectopterygoid is enlarged anteriorly in some halosauroids (Greenwood, 1977); how- ever, in none does it articulate directly with the ethmoid region. Anguilloids too generally have an elongated suspensorium and in Anguilla anguilla (Fig. 8) its anterior articulation is effected by a long, narrow bone which extends to the ethmoid region and may incorpor- ate the palatine (the palatopterygoid of Matsui & Takai, 1959) because an ossified auto- palatine was not observed in Anguilla. This bone was considered by Norman (1926) to be an endopterygoid. More recently, Leiby (1979 & 1981) has found that in several ophichthid anguilloids the endopterygoid and metapterygoid form a single compound bone which fuses during ontogeny with the anterior edge of the hyomandibula. He identifies the long narrow bone connecting the suspensorium and neurocranium as an ectopterygoid in these fishes (Leiby, 1979: fig. 2F& 1981: fig. 12A). The suspensorium in Anguilla has, superficially, a remarkably similar apearance to that in several of the more highly derived mastacembeloids, particularly Chaudhuria and Pillaia Com MC Aa Com MM\_/ g MC Com MC Com Com, Fig. 7 Medial view of the right coronomeckelian in: (a) Notograptus guttatus; (b) Rhyacichthys aspw, (c) Trichogaster leeri; (d) Sandelia capensis; (e) Luciocephalus pulcher, (f) Hypoptychus dy bows kit; (g) Callionymus lyra. MASTACEMBELOIDEI III PHYLOGENETIC 101 Palopt Hyo Pop HyoSP Fig. 8 Anguilla anguilla, left hyopterygoid arch and preoperculum in lateral view. MP Pal Fig. 9 Congrogadus subduceus, left hyopalatine arch and preoperculum in lateral view. (e.g. compare Travers, 1984: figs. 17 & 25 with Fig. 8). However, its anterior articulation in Anguilla is effected by what is apparently the ectopterygoid (which may have fused with the palatine) articulating with the ethmoid region and maxilla, whereas, in Chaudhuria and Pillaia the ectopterygoid, which is also attenuated (and possibly fused with the palatine), articulates with the lateral face of the vomerine shaft (see Travers, 1984: 83). The endopterygoid is enlarged, functionally replacing the ectopterygoid, in the congro- gadids. In Congrogadus subduceus and Haliophus guttatus (Fig. 9) the anterior end of the bone is connected to the palatine which articulates the suspensorium with the neurocranium. The ectopterygoid in these species is a short, narrow bone connected to the anterior edge of the quadrate, and lacks an anterior point of articulation with the skull. In synbranchids there is a large ectopterygoid which Rosen & Greenwood (1976: 44-48) imply is associated with the absence of the endopterygoid and with the massive development of the basisphenoid. They term this trend one of the 'special' attributes of all synbranchids. In Synbranchus marmoratus (Fig. 10) the ectopterygoid is connected posteriorly (by its anterodorsal, but subdistal process) to a basisphenoid projection, and also has a more usual distal articulation with the palatine. This additional abutment has developed between the ectopterygoid and frontal in Ophisternon aenigmaticum (Gosline, 1983: fig. 3B). The degree 102 R. A. TRAVERS FFac PalT Ect Fig 10 Synbranchus marmoratus, left palatopterygoid articulation to the neurocranium, lateral aspect. of enlargement of the ectopterygoid is particularly great in Monopterus albus (compare Rosen & Greenwood, 1976: figs. 59 & 61). The palatine in Monopterus lies further anteriorly than that in Synbranchus (e.g. com- pare Rosen & Greenwood, 1976: figs. 58 & 59) and its articulatory function (between suspensorium and lateral ethmoid) is taken over by the ectopterygoid in both species. The increase in the size of the ectopterygoid in synbranchids (p. 1 10) must be an apo- morphic feature because it culminates in the anterior displacement of the palatine (associ- ated with a reduction in the size of its maxillary process and its close adherence to the vomerine shaft) and, consequently, the establishment of a direct articulation between the ectopterygoid and lateral ethmoid in some taxa (e.g. Monopterus). Apart from these highly modified synbranchids, a direct articulation between the ectop- terygoid and the lateral ethmoid is an otherwise distinctive synapormorphy found only in the majority of mastacembeloids. A long, thin palatine sutured along the postero lateral face of the vomerine shaft, and lacking articulatory facets, is a characteristic feature of most mastacembeloid taxa. In those euteleosts with a distinct palatine this bone generally has moveable joints with the neurocranium and the upper jaw, viz., with the lateral ethmoid, usually involving a medial palatine facet, and anteriorly with the maxilla (cranial condyle) usually involving a short, often curved, maxillary process developed from the palatine. Although the pala- tine in higher euteleosts is variable in shape and dentition it was found to possess these articulatory functions in most lineages except the mastacembeloids and synbranchids. The mastacembeloid palatine is a straight bone that is sutured to the lateral face of the vomer/parasphenoid junction below the lateral ethmoid to which it may be connected by a weak ascending spur (Travers, 1984: 84). It lacks any moveable articulation and does not have a maxillary process. Posteriorly, the palatine extends below the orbit, is dorsoventrally flattened, and supports the anterior fibres of the adductor arcuspalatini muscle in this region. This highly derived palatine is typical of all mastacembeloids and is presumably associated with the lack of a protrusile upper jaw. The reductional trend in the synbranchid palatine is probably also associated with the loss of protrusibility of the upper jaw. In the more highly derived synbranchids (e.g. Monopterus) both the close adherence of the palatine to the vomerine shaft, and the lack of its connection to the lateral ethmoid are derived features (synapomorphies) shared with the mastacembeloids but with no other higher euteleosteans. Development of the mastacembeloid palatine appears to be at a more derived stage (i.e. no maxillary process or connection to the ectopterygoid) than is the synbranchid MASTACEMBELOIDEI II: PHYLOGENETIC 103 palatine. This arrangement of the palatine in mastacembeloids and synbranchids is closely associated with the development of the ectopterygoid in these taxa and, in combination, these characters provide important evidence in support of an hypothesis of shared common ancestry for the two groups, evidence consistent with the indications provided by the dentary (see p. 98) and posttemporal (p. 96) bones. BRANCHIAL ARCHES In most mastacembeloids a small, round, toothplate is fused to the dorsal surface of hypo- branchial 3 (see also Maheshwari, 1965: fig. 6). Apart from these fishes a fused toothplate features (see p. 103), it could be a reliable synapomorphy for uniting these groups. Its (e.g. Nandus & Badus} and channids (e.g. Channd). The possible means by which this fused toothplate has developed in Nandus, Badus and Channa, and its value as an indicator of phyletic relationships were discussed by Nelson (1969: 496-7). A fused toothplate on hypobranchial 3 is absent in Mastacembelus mastacembelus, Pillaia and in an assemblage of African species (T ravers, 1984: 94). In those species in which the toothplate is present, it is not always opposed by toothplates on epibranchial 1 . Toothplates on that element occur only in the larger predaceous species (e.g. Mastacembelus cunningtoni; Travers, 1984: fig. 64). Although a fused toothplate on hypobranchial 3 is a synapomorphy uniting most mastacembeloids, its mosaic distribution within the group and its occurrence in several phylogenetically distantly related taxa make it a character of limited taxonomic value when considered in isolation. A pair of processes descending from the posterolateral corners of basibranchial 2 are present in most mastacembeloids. The ventral tips of these processes are curved anteriorly and connect by converging ligaments to the posteroventral margin of basibranchial 1 (Travers, 1984: 92). Processes on basibranchial 2 have not been found in any outgroup taxa, their presence is treated as a synapomorphic character of the mastacembeloids, and further evidence in support of their monophyletic origin. DORSAL FIN SPINES The development of a series of spinous rays in the dorsal fin is a feature common to most acanthopterygian fishes. The number of dorsal spines may vary from a short row to a long series along the entire length of the dorsal surface in some fishes, e.g. the 'prickleback', Stichaeus hexagrammus. The spinous dorsal rays, regardless of their number, are generally interconnected by a thin membrane, however, this is absent in mastacembeloids. Isolated dorsal spines appear also in several notacanthid halosauroids. However, the spinous rays in these fishes have been shown by McDowell (1973: 143) to form ' . . . part of a (single dorsal) connected fin ... that is low and so heavily sheathed by scaly skin that only the separate tips of the spines are visible without dissection'. Furthermore, all these fishes lack a series of soft-rays posterior to the spinous part of the dorsal fin. Thus a dorsal fin composed of isolated short, stout spines anterior to a long series of soft rays must be a synapomorphy of the mastacembeloids as it is unique to the group. Myology CEPHALIC MUSCLES A number of myological features common to several mastacembeloid taxa were found to be unique to the group. The mastacembeloid levator operculi originates from the pterotic and inserts on the dorsolateral face of the operculum in all taxa examined (Travers, 1984: 119). The insertion of a levator operculi was described by Winterbottom (1974: 238) as the dorsal or dorsomedial face of the operculum. This is the condition in the majority of teleosts I have examined, and must be considered the plesiomorphic condition in neoteleosteans. A lateral insertion of fibres of the levator operculi, apart from in the mastacembeloids, was only found in species of the phylogenetically distantly related anguilloids (e.g. Anguilla anguilla), synbranchoids 104 R. A. TRAVERS (Liem, 1980a: 83) and blennioids (e.g. Notograptus guttatus). The lateral insertion oUevator fibres in all mastacembeloid and synbranchoid taxa suggests that, together with several other features (see p. 103), it could be a reliable synapomorphy for uniting these groups. Its occurrence in anguilloids and some blennioids in the absence of any further derived char- acters shared by these taxa and the mastacembeloids and synbranchoids, is interpreted as a convergence. A small independent muscle lies between the posterior edge of the preoperculum and anterolateral face of the operculum (ventral to the opercular lateral ridge) in all mastacem- beloids (Travers, 1984: fig. 79a), and is termed the 'musculus intraoperculi' (T ravers, 1984: 120) because of its position within the opercular series. Winterbottom (1974) describes no a AddMand Op Add Mand Sop Fig. 1 1 Ligamentous connection between the preoperculum and operculum in: (a) Cottus gobio; (b) Channa obscura. Lateral view, right side. MASTACEMBELOIDEI IK PHYLOGENETIC 105 muscle in this position in any teleost he examined; its absence is confirmed by all out- group taxa I have examined. Its unique occurrence in the mastacembeloids is a valuable synapomorphy for the group. A ligament between the posterior edge of the preoperculum and the anterolateral face of the operculum occurs in a number of phylogenetically diverse acanthomorph taxa. These include the cottoids (e.g. Agonus cataphractus, with a weak ligament between the preoper- culum and operculum and Coitus gobio with a broad strong ligament; Fig. 1 la), the gobioid Amblyopus broussonetti (in which a broad, weak collagenous band lies between the preoper- culum and operculum) and the channoids (e.g. Channa obscura, with a strong opaque ligament; Fig. lib). An origin of the adductor hyomandibulae from the posteroventral surface of the para- sphenoid is not recorded by Winterbottom (1974: 240), but this condition is typical of all mastacembeloids (Travers, 1984: 125). Also, a musculous insertion of this muscle partly on the medial face of the symplectic seems to be a general feature of all mastacembeloids and one not found in other groups (Winterbottom, 1974 gives the muscle's insertion site as the 'posterodorsomedial face of the hyomandibular'). The arrangement of these features of the adductor hyomandibulae were not always readily discernible in the outgroup taxa I examined they, therefore, remain doubtful additional synapomorphies of the group. The dorsal expansion of fibres of the hyohyoidei adductores above the upper branchio- stegal rays (medial to the suboperculum and operculum) and their insertion on the cleithrum, supracleithrum and posttemporal tubules in mastacembeloids (Travers, 1984: 128) is an unparalleled apomorphic development of this muscle. The general condition of the hyohyoidei adductores in teleosts is as a medial sheet of fibres extending only between the distal portions of the branchiostegal rays. Winterbottom (1974) noted that the fibres may continue dorsally above the posterodorsal ray to attach to the medial faces of some of the opercular bones, but in no teleost did he find the dorsal expansion continuing above the operculum and across the lateral face of the body muscles. I have examined the hyohyoidei in representatives of each major teleostean lineage, particularly those in which the opercular opening is restricted. The anguilloids, e.g. Anguilla anguilla, have a very restricted opercular opening effected in part by the filiform branchiostegal rays which curve up around the posterodorsal corner of the operculum; see McAllister (1968: 79). Fibres of the hyohyoidei adductores pass across the medial face of these long branchiostegal rays, but do not extend further dorsally or insert on the lateral face of the body. McAllister (op. cit.) found a close resemblance between the anguilloid branchiostegal arrangement and that in the myctophoids. Here the hyohyoidei adductores are of general teleostean proportions. The ophidioids (e.g. Carapus acus), zoarcoids (e.g. Zoarces viviparas) some blennioids (e.g. Pholis gunnellus), callionymoids (e.g. Callionymus lyrd) and the tetraodontoids (e.g. Diodori) are all acanthomorph lineages with some restriction of the opercular opening. In none, how- ever, do the hyohyoidei expand across the lateral wall of the body, although in some tetraodontoids they may expand medially and contact their partners in the midline (Winterbottom, 1974). The synbranchids (particularly members of the Synbranchinae; Rosen & Greenwood, 1976) have a very restricted opercular opening. The 4-6 branchiostegal rays may have their distal halves poorly ossified in a number of synbranchids (Rosen & Greenwood, 1976), and although the family is characterised by small opercular bones, the branchiostegal apparatus and its musculature are hypertrophied (Liem, 1980 S ojS'oS 33 s f ^ o ? 9P 8 e |"5 o > y s ^ -2 VJ S. >> s: 'C 5" Q i ~ -~ c ~ o .2 ^ 5 5U -c 5 ^ G a ' s . ?i 2P c - o .s 5 >> c ^ js a > H-'- S ^ X" % c c |.S "O *O ^> 3.> a " 5 S _. vi I .= ^ c - . ^ (U 3 a E 5 se -G g. - g. ^2, c c -^ '"" v- ^ * o i S 5 00 'o C ^ G -C) 5 ^ MASTACEMBELOIDEI III PHYLOGENETIC 135 This character is present in Mastacembelus armatus, M. erythrotaenia, M. mastacem- belus, M. oatesii and M. unicolor. Mastacembelus aiboguttatus is tentatively assigned to this group because of its superficial resemblance to the other members, but lack of material precludes a definite decision on its membership. No other characters were found that make it possible to analyse further the interrelation- ships of these 6 species which, therefore, are treated as an unresolved polychotomy (D). If polychotomies of this type prove to be inherently unresolvable they could reflect an evolutionary reality (Eldredge & Crancraft, 1980). The other sublineage stemming from the 5th node (E to J) is defined by 8 synapomorphies, represented by the 6th node in the cladogram, viz: 6 1 . Posterior region of parasphenoid undivided, apart from its tip, and excavated to form a pit-like depression on ventral surface (p. 111). 62. Expanded ventrolateral face of exoccipital and postero ventral margin of basioc- cipital, associated with deep basicranium (p. 111). 63. Deep basioccipital fossa accommodates anterior end of Baudelot's ligament (p. 1 1 1 ). 64. Dorsal surface of frontal slopes ventrolaterally (p. 1 13). 65. Elongate narrow neural and haemal spines, associated with a deep body (p. 126). 66. Relatively low total vertebral count (see p. 126 & Travers, 1984: table 5). 67. Distinct anterior part of adductor arcus palatini muscleiinserts on the attenuated posterior edge of the 1st infraorbital (p. 130). 68. 6 slender, digitiform fimbriae around rim of each anterior nostril, associated with relatively long rostral appendage (p. 1 30). This sublineage contains the remaining 8 Mastacembelus species recognised by Sufi (1956) and the 3 Macrognathus species recognised by Roberts (1980). It represents a monophyletic assemblage defined by at least 3 unique synapomorphies (6 1 , 67 & 68). Apart from the char- acters visible without dissection (e.g. 64 & 68), and those visible in radiographs (e.g. 65 & 66), the remaining characters could not be checked in every species because suitable material for dissection was not always available. For that reason Mastacembelus guentheri, M. keithi and M. perakensis have been placed with Mastacembelus circumcinctus, M. caudiocellatus and M. maculatus in an unresolved polychotomy (E) pending further research. Detailed studies of Mastacembelus zebrinus, Mastacembelus pancalus, Macrognathus aculeatus, Macrognathus aral and Macrognathus siamensis however, have revealed a nested series of synapomorphic characters which clearly show the phylogenetic affinity of these species (F to J). The 7th node represents the 7 synapomorphies shared by species F to J, viz: 69. Anterolateral expansion of premaxillary tooth-bearing alveolar surface (p. 1 13). 70. Low and broad coronoid process on dentary associated with tendency for its medial face to the toothed (p. 1 1 4). 71. Dorsal edge of anguloarticular with low, broad-based coronoid expansion (p. 1 15). 72. Indented anterolateral edge of quadrate (p. 1 16). 73. Tendency for ventral limb of cleithrum to develop a wide lateral face (p. 125). 74. Loss of the maxillo-mandibular ligament (p. 129). 75. Tendency for A, to become the largest part of the adductor mandibulae muscle, and for tA, to be a long, strap-like tendon extending to rostral appendage (p. 129). This suite of characters could be considered as a single transformation as they appear to be closely correlated (i.e. all can be functionally associated with the jaw mechanism) and may result from a common heterochronic ontogenetic shift. Mastacembelus zebrinus (species F) shows the suite of synapomorphies represented by the 7th node in the cladogram and is defined by two autapomorphies: 76. Extremely wide ventrolateral face of cleithrum producing 'keeled' pectoral girdle (p. 125). 77. Urohyal ascending process long and thin, its dorsal tip contacting basibranchial 2 and anterior margin connected to the posterior edge of the keel on basibranchial 1 (p. 123). 136 R. A. TRAVERS The 8th node represents 3 synapomorphies that unite Mastacembelus pancalus (species G) more closely with the Macrognathus species than to any other mastacembeloid. These characters are: 78. Loss of palatine spur (p. 118). 79. Preopercular sensory canal with 3 central pores at the end of short descending branches (p. 1 19). 80. Basibranchial 1 keel with a cartilaginous ventral edge and direct articulation with the urohyal (p. 122). Although characters 79 and 80 are both neomorphs, character 78 is a reductional one and as such could have arisen independently (see p. 118) as it does in Mastacembelus macula- tus. However, in combination with the two other apomorphic characters it is considered to be a reliable indicator of the close phylogenetic relationship between these species. Mastacembelus pancalus is defined by a single autapomorphy: 8 1 . Faceted connection between anteromedial margin of quadrate and posterolateral face of ectopterygoid (p. 1 18). The 9th node in the cladogram represents 3 synapomorphies that unite the Macrognathus species (H to J). These can be summarised as follows: 82. Fragmentation of premaxillary toothbearing alveolar surface into small pairs of plates along ventral surface of the rostral appendage (p. 1 14). 83. Dorsal edge of anguloarticular notched by facet anterior to posterodorsal corner of the bone (p. 1 15) and flange on lateral commissure of prootic (p. 1 12). 84. Low number of dorsal spines resulting from loss of anterior elements in the series (P. 127). Character 82 is the underlying synapomoprhy of this group and its division into a further 3 separate states (85, 88 & 89) clearly demarcates the Macrognathus species each from the other. Macrognathus aculeatus (species H) can be defined by the state of the group's synapomorphy, and by a 2nd apomorphic character: 85. Rostral toothplates usually in 38-55 pairs (p. 1 14). 86. Extremely large basisphenoid, associated with wide opening to posterior myo- dome (see Travers, 1984: 53 & fig. 30a & b). The 10th node represents a single synapomorphy which indicates the closer relationship of M. aral (species I) and M. siamensis (species J) to one another than either is to Macrognathus aculeatus. 87. Deeply notched posterolateral margin of pterosphenoid forming anterior region of trigeminal foramen (see Travers, 1984: 65 & fig. 29a). Macrognathus aral and Macrognathus siamensis, respectively, may be defined by the state of the group synapomorphy (i.e. 82) in each species: 88. Rostral toothplates: 14-28 pairs (p. 1 14). 89. Rostral toothplates: 7-14 pairs (p. 1 14). The llth node represents 4 synapomorphies uniting members of the 2nd branch of the main dichotomy (the 4th node in the cladogram). The synapomorphies uniting this assemblage, which includes all the African taxa but no others, are: 90. Lack of ascending process on urohyal or direct articulation between this bone and basibranchial 1 (p. 122). 9 1 . Hypural plates, generally 2; tendency for parhypural fusion to ventral edge of lower plate; 8-10 principal fin rays and confluent caudal fin (p. 128). 92. Scapula foramen not completely bone enclosed (p. 125). 93. Tendency to have noticeably more caudal than abdominal vertebrae (p. 126). MASTACEMBELOIDEI II: PHYLOGENETIC 137 Within this assemblage, 2 major subdivisions (K, and L to S in the cladogram) can be recognised. Subdivision K serves, for the time being, as a 'catch-all' assemblage for species united by the presence of synapomorphies 90-93. No other characters could be determined which would allow further subdivision of the group which, therefore, is represented as an unresolved polychotomy. Included in this group are Mastacembelus albomaculatus, M. cunningtoni, M. ellipsifer, M.flavidus, M.frenatus, M. micropectus, M. moorii, M. ophidium, M. plagiostomus, M. platysoma, M. tanganicae, M. zebratus, M. congicus, M. shiranus, M. stappersii and M. vanderwaali. A number of other nominal species (listed in Travers, 1984: table 1), for which material was unavailable should probably also be included. The second major subdivision (L to S) is represented by the 12th node in the cladogram, and is denned by 2 synapomorphies: 94. No toothplate on pharyngobranchial 2 (p. 124). 95. Less than 5 preopercular sensory canal pores (p. 1 19). Both these are loss features, and each has arisen separately, but never in combination (see p. 1 19 & 124), in several of the species lumped provisionally in species complex K. Since these characters are found in combination only in taxa L to S, they are taken to indicate the phylogenetic unity of the assemblage. Group L to S (12th node in cladogram) can be subdivided into two sub-groups; L and M to S. L is a polychotomy (discussed on p. 123) of at least 15 species viz: Mastacembelus batesii, M. brevicauda, M. flavomarginatus, M. goro, M. greshoffi, M. liberiensis, M. loennbergii, M. longicauda, M. marchii, M. marmoratus, M. niger, M. nigromarginatus, M. reticulatus, M. sclateri, and M. ubangensis, and may possibly include several of the species for which study material was unavailable (see Travers, 1984: table 1). The second group contains species M to S, viz: Mastacembelus paucispinis, M. brachyrhinus, M. brichardi, M. latens, M. crassus, M. aviceps and the undescribed species (see p. 1 1 9). Group L is denned by 2 synapomorphies: 96. Loss of anterior process on hypobranchial 3, and no ligamentous connection to basibranchial 2 (p. 124). 97. Arched ventral processes on basibranchial 2 (p. 123). Although character 96 is a reductional one it is atypical of the condition in most outgroup taxa and is found in no other mastacembeloids. Therefore, it should be treated as a derived feature. Character 97 is a synapomorphic feature for this lineage. No other characters were found which would enable the interspecific relationships of these species to be resolved further, for the present they remain as an unresolved polychotomy. This is not the case for the second group of the 12th dichotomy. Taxa in this branch are united by 3 synapomorphies represented by the 1 3th node, viz: 98. A reduction in the number of preopercular sensory canal pores (p. 1 19). 99. Loss of toothplate on hypobranchial 3 (p. 124). 100. A reduction in the number of caudal vertebrae (p. 126). Although character 99 mimics the plesiomorphic condition, it is thought to be a secondary reduction that has arisen, independently, in some species recognised as part of polychotomy L (see p. 124). In combination, however, these characters are considered to be a unique synapomorphy suite for the species in which they occur (i.e. M to S). Detailed analysis of the species in this group has led to the resolution of their interspecific relationships. The 14th node in the cladogram represents 2 synapomorphies shared by Mastacembelus paucispinis and the undescribed Mastacembelus species. These are taken as indicative of the taxa being more closely related to one another than either is to any other species. These synapomorphies are: 101. Low number of dorsal spinous rays (their loss occurring posteriorly in the series), combined with a long soft rayed dorsal fin that extends across the junction between abdominal and caudal vertebrae (p. 127). 138 R. A. TRAVERS 102. Tendency for the anterior tip of the prootic to form a bridge by contacting the ventral edge of a pedicel on the frontal (p. Ill ). Although character 101 is a synapomorphy for both species, it can be separated into 2 states, each of which is species specific. Thus, Mastacembelus paucispinis (species M) can be defined by its having: 103. 7-10 dorsal spines (p. 127). and the undescribed Mastacembelus species (N) by its having: 104. 15-16 dorsal spines (p. 127). The 1 5th node in the cladogram represents 3 synapomorphies uniting the remaining 5 species, viz: 105. Loss of pleural ribs from the anterior abdominal vertebrae (p. 126). 106. Coronomeckelian very short (p. 1 15). 107. Part A 2 of the adductor mandibulae hypertrophied (p. 130). These taxa can be considered a small species flock as they are endemic to the highly specialised rapids environment of the Lower Zaire River and conform to the prerequisite criteria discussed by Greenwood (1984). Of their features, 105 is a reductional one which does occur in some species provisionally assigned to species complex K (see p. 126). Whether this indicates that it has occurred independently in these various taxa or whether it indicates that the species in K may eventually be included in this group (O to S), cannot be determined at present. Mastacembelus brachyrhinus (species O) may be distinguished from other species associ- ated through node 1 5 by a single autapomorphic feature: 108. Dorsal expansion of the pterotic, associated with relatively small parietals, posterior expansion of frontals, and a tendency for the extrascapulae to be independent (p. 97). The 16th node represents the following 4 synapomorphies: 109. Relatively large saccular bulla (accommodated entirely within the prootic, see p. 112). 1 10. Short anterior region of frontal; roofs small orbital cavity (see p. 1 13). 111. Endopterygoid very small and splinter-like (see p. 1 16). 1 12. Ventral limb of cleithrum short and indistinct (p. 125). 113. Tendency to be microphthalmic or cryptophthalmic (p. 1 13 & 130). These synapomorphies unite Mastacembelus brichardi (species P), Mastacembelus crassus (species R) and Mastacembelus aviceps (species S), and probably Mastacembelus latens (species Q) as well, although lack of material precludes a definite allocation of this species. Mastacembelus brichardi may be distinguished from the other species by 2 autapomorphies, viz: 1 14. Loss of pigment (p. 85). 115. Eyes extremely small and lying medial to the levator arcus palatini muscle (see Travers, 1984: 125 & fig. 84b). The remaining taxa in the lineage containing species M to S are Mastacembelus crassus (R), M. aviceps (S) and, probably, M. latens (Q). The 1 7th node in the cladogram represents 6 synapomorphies for these species, viz: 116. Scaleless(p. 129). 1 17. Loss of basisphenoid (p. 1 10). 1 18. Anterior process of prootic very short or absent (p. 111). 1 19. Ectopterygoid with narrow anterolateral face (p. 1 18). MASTACEMBELOIDEI II: PHYLOGENETIC 139 120. Dorsal opening of preopercular sensory canal on the posterior edge of preoperculum (p. 119). 121. Low 'keel' on basibranchial 1 (p. 121). Mastacembelus latens is provisionally included in this group on the grounds that it shares one of these apomorphic characters (116). Until specimens of M. latens are available for dissection, the presence or absence of the other 5 synapomorphies cannot be determined. The 6 synapomorphies shared by Mastacembelus crassus and Mastacembelus aviceps (and possibly M. latens) are all reductional ones. Several of these characters (all, apart from 120 & 12 1 ), or at least the tendency for their manifestation, are seen in Pillaia and in Chaudhuria (to a lesser extent). However, these taxa are clearly more closely related to Mastacembelus sinensis (as discussed on p. 128) and this complex of 6 characters in combination is an indicator of the close phyletic affinity of M. crassus and M. aviceps. Mastacembelus crassus (species R) can be distinguished from Mastacembelus aviceps (S) by a single apomorphic character, viz: 122. Tendency for the trigeminal and facial foramina to be confluent (p. 111). Whereas, M. aviceps can be identified by a combination of 5 apomorphic features, of which three are autapomorphic (i.e. 123, 124 & 125), viz: 123. Extremely small, splinter-like pterosphenoid lying along dorsolateral edge of frontal (p. 110). 124. Loss of neurocranial precommissural lateral wall and trigeminofacialis foramina (Travers, 1984: 68 & fig. 40a & b). 125. Anterior region of maxilla reduced to a weak and thin process tightly connected to premaxilla (p. 1 13). 126. Loss of ventral processes on basibranchial 2 (p. 123). 127. Hypurals fused into single fan-like plate (p. 128). These characters, and that defining M. crassus are all reductional ones; one of them (char- acter 127) also occurs in Mastacembelus ellipsifer (see p. 128), and is a further example of a reductional feature developing independently. Proposed changes in classification Comparison of the present state of mastacembeloid taxonomy (Fig. 18) with the phylogeny of the group (Fig. 20) reveals the necessity for numerous alterations to the existing classifi- cation, if the phylogenetic relationships of the species are to be reflected. These taxonomic and nomenclatural changes can be summarised as follows: Re-allocation of the Mastacembeloidei from the Perciformes to the Synbranchiformes, as a sister taxon of the Synbranchoidei. Expansion of the family Chaudhuriidae to incorporate two genera. Elevation of Mastacembelus sinensis to a monotypic genus of the Chaudhuriidae. The generic synonymy of Chaudhuria with Pillaia (and Garo see p. 109), but retention of both taxa as subgenera of Chaudhuria. Division of the Mastacembelidae into two subfamilies (representing the Asian and African species, respectively). Restriction of the Mastacembelus generic concept to five Asian and one Middle Eastern species only. Expansion of the Macrognathus generic concept to include eight Asian species previously included in Mastacembelus. Creation of a new subfamily for the African taxa. Creation of new genera for the major African sublineages. 140 R. A. TRAVERS .0 I MASTACEMBELOIDEI III PHYLOGENETIC 141 Diagnoses for the Synbranchiformes, its suborders, families, subfamilies and genera Order SYNBRANCHIFORMES Berg 1940 Berg, L. S., 1940. Classification of fishes, both recent and fossil. Trav. Inst. Zoo/. Acad. Sci. U.S.S.R. 5: 1-517, (English translation). DIAGNOSIS. Eel-shaped acanthomorph fishes of small to moderate size (attaining max. length of approx. 1 m). Burrowing and cavernicolous habit commonly displayed. Lack pelvic fins or girdle, with caudal fin reduced or absent. Gill membrane attached to lateral wall of body by expansion of hyohyoidei adductores muscle; restricted opercular opening and insertion of levator operculi on lateral face of operculum. Prominent adductor mandibulae muscula- ture, with part A, lying ventral to A 2 , the latter tending to encroach across dorsal surface of neurocranium and into orbital cavity. Eyes small and well forward in skull. Anterior and posterior nostrils. Cycloid scales, small and oval, sometimes absent. Neurocranium attenuated, particularly precommissural region involving frontals, pterospenoid, vomer and parasphenoid; dorsal surface lacks crests or any form of sculpturing. Frontals turned down with prominent descending lamina. Infraorbital bones reduced apart from 1st. Palatines joined firmly to vomer in midline; generally tooth bearing. Vomer a long thin strut. Ecto- pterygoid articulates with lateral ethmoid, vomer or both. Non-protrusile upper jaw. Maxilla and premaxilla long and strut-like, with symphyseal and articulatory processes reduced or absent. Dentary with posterior extension along ventral edge of anguloarticular. Pectoral girdle remote from basicranium, posttemporal bone reduced (accompanied by loss of connection to pectoral girdle) or lost. Flexible craniovertebral joint. Dorsal gill arch skeleton positioned posteriorly; lacks first pharyngobranchial bone, with second pharyngobranchial reduced or absent. Numerous vertebrae. Pantropical and subtropical fishes from freshwaters at high and low elevations; some individuals reported from brackish waters; tendency for facultative air breathing and sex re- versal. 83 extant species currently recognised (no fossil record) in two suborders. Suborder SYNBRANCHOIDEI Boulenger, 1904 Boulenger, G. A., 1904. A synopsis of the suborders and families of teleostean fishes. Ann. Mag. nat. Hist. (7), 13: 161-190. DIAGNOSIS. Monotypic suborder with synbranchiform features given above. For annotated account of groups, species diagnoses and key see Rosen & Greenwood (1976: 49-66). Suborder MASTACEMBELOIDEI Greenwood et at, 1966 Greenwood, P. H., Rosen, D. E., Weitzman, S. H. & Myers, G. S. 1966. Phyletic studies of teleostean fishes, with a provisional classification of living forms. Bull. Am. Mm. nat. Hist. 131: 339-456. OPISTHOMI Boulenger, G. A., 1904. Ann. Mag. nat. Hist. (7), 13: 161-190. (subordinal rank). Regan, C. T., 1912. Ann. Mag. nat. Hist. (8), 9: 217-219 (ordinal rank). MASTACEMBELIFORMES Berg, L. S., 1940. Trav. Inst. Zoo/. Acad. Sci. U.S.S.R. 5: 1-517. DIAGNOSIS. Synbranchiform fishes with long dorsal and anal fin composed of isolated spinous rays anterior to long series of soft branched rays. Rostral appendage formed from anterior nostrils (at end of tubular extensions) positioned lateral to a central rostral tentacle. Rim of anterior nostril generally with two wide (fimbrules) and two narrow (fimbriae) flaps of skin. 'Musculus intraopercuW differentiated within opercular series. Elongate ethmovomer- ine region with long nasal and 1st infraorbital bones. Preorbital spine (posterior tip of 1st infraorbital) generally pierces skin. Tubular lateral ethmoids accommodate anterior end of massive nervus olfactorius. Pterosphenoids, joined firmly in midline; frontals completely en- close foramen magnum. Small compressed basisphenoid, occasionally absent. Anterior re- gions of prootic and sphenotic attenuated; former having long process extending into orbital cavity and latter having wide lateral flange. Saccular bulla generally small and house entirely 142 R. A. TRAVERS within the prootic. Extrascapulae (lateral and medial) lost and sensory canal enclosed by parietal. 'Ball and socket' craniovertebral joint. Obliquus superioris with anterior insertion on posterior edge of exoccipital. Posterior end of Baudelot's ligament forked. Very large cor- onomeckelian dorsal to dentary, across lateral face of suspensorium. Pair of ventral processes on basibranchial 2. Hypobranchial 3 with a round toothplate fused to dorsal surface. Pseudo- branch present. Ethiopian and Oriental distribution. Wide range in tropical and subtropical Africa, and in Asia continuously from Middle East to islands of Indonesia, and eastern China seaboard. 68 species currently recognised, in two families. Family CHAUDHURIIDAE Annendale, 1918 Annendale, N., 1918. Fish and fisheries of the Inle Lake. Rec. Ind. Mm. 14: 33-64. TYPE GENUS. Chaudhuria Annendale, 1918. DIAGNOSIS. Derived mastacembeloid fishes with above features but tending to small adult size and reduction or loss of many characters by heterocrony. Rostral appendage reduced or lost. Needle-like parasphenoid posterior processes. Dorsomedial region of exoccipital with perforated dorsal surface and separated from opposite number. 1-2 inner rows of pre- maxillary teeth. Ectopterygoid with narrow lateral face and very long antero-dorsal process. Palatine reduced in size (lacks suborbital flange). Three or fewer epicentral ribs. Interdigi- tating processes of anterior and posterior ceratohyals reduced or lost. No endopterygoid, basibranchial 2 ventral processes or epipleural ribs. Confined to China (including Taiwan and possibly Korea), Thailand, Burma and northern India. Family expanded to incorporate 4 species in two genera. Genus RHYNCHOBDELLA Bloch & Schneider, 1 80 1 Blotch, M. E. & Schneider, J. G., 1801. M. E. Blochii Systema Ichthyologiae iconibus ex illustratum. Post oblitum auctoris opus inchoatum absolvit, correxit, interpolavit . . . J. G. Schneider, Saxo. Berolini. TYPE SPECIES. Rhynchobdella sinensis Bleeker, 1870 DIAGNOSIS. Monotypic chaudhuriid genus. Parietals may contact medially; very large 3rd anal spine equal in size to the 2nd spine and separated from it by four vertebrae. Tip of vertical urohyal ascending process contacts underside of basibranchial 2. Widely distributed in China, Taiwan and possibly N. & S. Korea. Genus CHA UDHURIA Annendale, 1918 Annendale, N., 1918. Fish and fisheries of the Inle Lake. Rec. Ind. Mus. 14: 33-64. Pillaia Yazdani, G. M., 1972. J. Bombay Nat. Hist. Soc. 69(1): 134-135; Talwar, P. M., Yazdani, G. M. & Kundu, D. K., 1977. Proc. Indian Acad. Sci. 85: 53-6. Garo Yazdani, G. M. & Talwar, P. M., 1981. Bull. zool. Surv. India 4(3): 287-288. TYPE SPECIES. Chaudhuria caudata Annendale, 1918 DIAGNOSIS. Highly derived chaudhuriid fishes with particularly small adult size (generally between 40-60 mm.). Extreme reduction of many features appears to mimic plesiomorphic condition e.g. large saccular bulla partly within prootic, exoccipital and basioccipital, coronomeckelian reduced to a small ossicle on medial face of anguloarticular. Loss of numerous features including; pterosphenoid, basisphenoid, frontal ventral lamina, cephalic sensory canal system (reduced or lost), palatine, pharyngobranchial 2 toothplate, dorsal and anal spines, and scales. Lack of ectopterygoid articulation with lateral ethmoid (ectoptery- goid directly contacts lateral face of vomerine shaft); possibly associated with loss of palatine. Posterior end of vomer ventrally depressed; pars jugularis pierced by single relatively large foramen. MASTACEMBELOIDEI III PHYLOGENETIC 143 Three species confined to Thailand, Burma and northern India: Chaudhuria caudata Annendale, 1918 Chaudhuria indica (Yazdani), 1972 Chaudhuria khajuriai (Talwar, Yazdani & Kundu), 1977. Family MASTACEMBELIDAE Gunther, 1861 Giinther, A., 1861. Catalogue of the acanthopterygian fishes. 3. London. TYPE GENUS. Mastacembelus Scopoli, 1777 DIAGNOSIS. Mastacembeloid fishes with features as for the suborder (given above) and, additionally: wide separation of hyomandibula and metapterygoid, associated with large symplectic. 64 species widespread throughout the range of the suborder. Two subfamilies comprise the mastacembeloids Oriental and Ethiopian regions. Subfamily MASTACEMBELINAE subfam. nov. TYPE GENUS. Mastacembelus Scopoli, 1777 DIAGNOSIS. Mastacembelid fishes with distinct caudal fin generally unconnected to posterior ray of dorsal or anal fin. If connected (by membrane) caudal fin rays extend posterior to, and remain distinct from, last posterior dorsal and anal fin ray. Caudal fin skeleton with 4 separate and autogenous hypural plates. Rostral appendage varies from very large to intermediate size. Tendency to be brightly coloured. 1 7 species widely distributed from Middle East to SE. Asia including China and continen- tal islands of Indonesia, arranged in two genera. Genus MASTACEMBELUS Scopoli, 1777 Scopoli, J. A., 1777. Introductio ad Historiam Naturalem, Prague. TYPE SPECIES. Mastacembelus mastacembelus (Banks & Solander, in Russell), 1794; See Wheeler, 1955. DIAGNOSIS: Mastacembeline fishes of moderate to large size (over 50 cm.). Attenuated anterior arm of endopterygoid lies between ectopterygoid and lateral ethmoid connection. Neurocranium broad with rostral appendage of moderate size. 6 species, five widely distributed in SE. Asia including the continental islands of Indonesia: Mastacembelus alboguttatus Boulenger, 1893 Mastacembelus armatus (Lacepede), 1 800 Mastacembelus erythrotaenia Bleeker, 1870 Mastacembelus oatesii Boulenger, 1893 Mastacembelus unicolor (Kuhl & van Hasselt) Cuv. & Val., 1831 and the single Middle Eastern species: Mastacembelus mastacembelus (Banks & Solander, in Russell), 1794. Genus MACROGNATHUS Lacepede, 1800 Lacepede, B., 1 800. Histoire naturelle des poissons. Paris 2. TYPE SPECIES. Ophidium aculeatum Bloch, 1786 DIAGNOSIS. Mastacembeline fishes of moderate to small size (under 50 cm.). Deep bodied with elongate, narrow neural and haemal spines. Rostral appendage large and more elongate than in other mastacembeloids. Six slender and digitiform fimbriae surround rim of each anterior nostril. Distinct anterior part of adductor arcus palatini muscle inserts on attenuate posterior edge of 1st infraorbital. Narrow, but deep, neurocranium with dorsal surface of 144 R. A. TRAVERS frontals sloping ventrally; ventrolateral face of exoccipital and posteroventral margin of basioccipital expanded. Posterior region of parasphenoid undivided (apart from tip) and excavated to form pit-like depression on ventral surface of basicranium (for muscle attach- ment). Deep basioccipital fossa accommodates anterior end of Baudelot's ligament. Vertebral count relatively low. In addition, see diagnosis given by Roberts (1980: 387). Roberts' (1980) Macrognathus generic concept (i.e. Macrognathus aculeatus, M. ami and M. siamensis) now expanded to include eight Oriental species previously assigned to Mastacembelus (i.e. 'Mastacembelus' caudiocellatus, 'M'. circumcinctus, 'M'. guentheri, 'M'. keithi, 'M'. macula- tus, 'M'. pancalus, 'M'. perakensis and 'M'. zebrinus). 1 1 species widely distributed in SE. Asia and continental islands of Indonesia: Macrognathus aculeatus (Bloch), 1786 Macrognathus aral (Bloch & Schneider), 1801; see Roberts, 1980 Macrognathus siamensis (Giinther), 1861; see Roberts, 1980 Macrognathus caudiocellatus (Boulenger), 1 892 Macrognathus circumcinctus (Hora), 1924 Macrognathus guentheri (Day), 1865 Macrognathus keithi (Herre), 1 940 Macrognathus maculatus (Cuv. & Val.), 1 83 1 Macrognathus pancalus Hamilton Buchanan, 1822 Macrognathus perakensis (Herre & Myers), 1937 Macrognathus zebrinus (Blyth), 1859 Subfamily AFROMASTACEMBELINAE subfam. nov. TYPE GENUS. Afromastacembelus gen. nov. DIAGNOSIS. Mastacembelid fishes with confluent caudal fin rays continues with posterior rays of dorsal and anal fin. Caudal fin skeleton generally with two separate and autogenous hypurals, tend to have parhypural fused to lower edge of ventral element and to have only 8-10 principal fin rays. Loss of ascending process on urohyal and direct articulation between urohyal and basibranchial 1 . Scapula foramen not completely bone enclosed. Tendency to have noticeably more caudal than abdominal vertebrae. This subfamily represents the Ethiopian mastacembelid species widely distributed throughout tropical and subtropical regions of the continent. 46 species currently recognised and provisionally arranged in two genera. Genus CAECOMASTACEMBELUS Poll, 1958 Poll, M., 1958. Description d'un poisson aveugle nouveau du Congo Beige appartenant a la famille des Mastacembelidae. Revue Zool. Bot. Afr. 57: 388-392. TYPE SPECIES. Caecomastacembelus brichardi Poll, 1958 DIAGNOSIS. Afromastacembeline fishes of small to moderately large size. With no pharyngo- branchial 2 toothplate and less than five preopercular sensory canal pores. Species with atrophied eye tissues and one (i.e. type for genus) is anoptic. General morphological simplifi- cation (by secondary reduction and loss) occurs in microphthalmic and cryptophthalmic species (parallels condition in Chaudhuria, although not carried to such extremes). Distributed predominently in western half of continent and includes small species flock endemic to lower Zairean rapids. At least 22 species tentatively assigned to this genus, and probably several more, for which study material was unavailable (see Travers, 1984: table 1): Caecomastacembelus aviceps (Roberts & Stewart), 1976 Caecomastacembelus batesii (Boulenger), 1911 Caecomastacembelus brachyrhinus (Boulenger), 1899 Caecomastacembelus brevicauda (Boulenger), 1911 Caecomastacembelus brichardi Poll, 1958 MASTACEMBELOIDEI III PHYLOGENETIC 145 Caecomastacembelus crassus (Roberts & Stewart), 1976 Caecomastacembelus flavomarginatus (Boulenger), 1898 Caecomastacembelus goro (Boulenger), 1902 Caecomastacembelus greshoffi (Boulenger), 1901 Caecomastacembelus latens (Roberts & Stewart), 1976 Caecomastacembelus liberiensis (Steindachner), 1 894 Caecomastacembelus loennbergii (Lonnberg), 1895 Caecomastacembelus longicauda (Boulenger), 1907 Caecomastacembelus marchii (Sauvage), 1 892 Caecomastacembelus marmoratus (Perugia), 1 892 Caecomastacembelus niger (Sauvage), 1878 Caecomastacembelus nigromarginatus (Boulenger), 1898 Caecomostacembelus paucispinis (Boulenger), 1899 Caecomastacembelus reticulatus (Boulenger), 1911 Caecomastacembelus sclateri (Boulenger), 1903 Caecomastacembelus ubangensis (Boulenger), 191 1 Caecomastacembelus sp. and probably: Caecomastacembelus ansorgii (Boulenger), 1905 Caecomastacembelus cryptacanthus (Giinther), 1867 Caecomastacembelus laticauda (Ahl), 1937 Caecomastacembelus sanagali (Thys van den Audenaerde), 1972 Caecomastacembelus seiteri (Thys van den Audenaerde), 1972 Genus AFROMASTACEMBELVS gen. nov. TYPE SPECIES. Mastacembelus tanganicae Giinther, 1893 DIAGNOSIS. Afromastacembeline fishes of moderate to large size; occur predominently from eastern half of continent and include species endemic to Lake Tanganyika. All afromasta- cembeline species, other than those assigned to Caecomastacembelus, provisionally lumped in this 'catch-all' assemblage (which may not be monophyletic) pending closer examination of groups interspecific relationships. At least 16 species tentatively placed in this genus, and probably several more, for which study material was unavailable (see Travers 1984: table 1). Afromastacembelus albomaculatus (Poll), 1953 Afromastacembelus congicus (Boulenger), 1 896 Afromastacembelus cunningtoni (Boulenger), 1906 Afromastacembelus ellipsifer (Boulenger), 1 899 Afromastacembelus flavidus (Matthes), 1962 Afromastacembelus frenatus (Boulenger), 1901 Afromastacembelus micropectus (Matthes), 1962 Afromastacembelus moorii (Boulenger), 1898 Afromastacembelus ophidium (Giinther), 1893 Afromastacembelus plagiostomus (Matthes), 1 962 Afromastacembelus platysoma (Poll & Matthes), 1 962 Afromastacembelus shiranus (Giinther), 1 896 Afromastacembelus stappersii (Boulenger), 1914 Afromastacembelus tanganicae (Giinther), 1893 Afromastacembelus vanderwaali (Skelton), 1976 Afromastacembelus zebratus (Matthes), 1962 and probably: Afromastacembelus moeruensis (Boulenger), 1914 Afromastacembelus signatus (Boulenger), 1905 Afromastacembelus trispinosus (Steindachner), 1911 146 R. A. TRAVERS The revised classification can be summarised as follows: Series: Percomorpha (consists of 1 2 orders) Order: Synbranchiformes Suborder: Synbranchoidei Family: Synbranchidae (see Rosen & Greenwood, 1976) Suborder: Mastacembeloidei Family: Chaudhuriidae Rhynchobdella Chaudhuria Family: Mastacembelidae Subfamily: Mastacembelinae Mastacembelus Macrognathus Subfamily: Afromastacembelinae Caecomastacembelus Afromastacembelus Acknowledgements I am indebted to the Trustees of the British Museum (Natural History), and the Keeper of Zoology for access to the collections and necessary research facilities. Again, it is a pleasure for me to thank the staff in the Fish Section (and all associated with it) for their generous support and tolerance of many ichthyological 'teething' problems. In particular I warmly thank Dr P. H. Greenwood, for painstaking criticism of an earlier draft, and Gordon Howes; both of whom have been a continual source of inspiration. I also take great pleasure in thanking Dr D. R. Kershaw for contributions of a supervisory kind and Prof. A. D. Hoyes for his encouragement and support. Maintenance from Queen Mary College (Drapers' Studentship), the University of London (Univer- sity Studentship and Central Research Fund) and the Godman Exploration Fund (British Museum (Natural History)) is acknowledged with gratitude. Loans and gifts of specimens for this study were generously donated by (in addition to those mentioned in Part I); Dr V. G. Springer (USNM). Finally, my mother (Helen Travers) deserves special mention for typing and retyping well beyond the call of duty. References Alberch, P., Gould, S. J., Oster, G. F. & Wake D. B. 1979. Size and shape in ontogeny and phylogeny. Paleobiology 5: 296-3 1 7. Berg, L. S. 1940. Classification of fishes both recent and fossil. Trav. Inst. Zoo/. Acad. Sci. U.S.S.R. 5: 87-517, (English translation). Bhargava, H. N. 1953. Pseudobranch in Mastacembelus. Curr. Sci. 22: 343-344. 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Manuscript accepted for publication 25 May 1983 British Museum (Natural History) Tilapiine fishes of the genera Sarotherodon, Oreochromis and Danakilia Dr Ethelwynn Trewavas The tilapias are cichlid fishes of Africa and the Levant that have become the subjects of fish-farming throughout the warm countries of the world. This book described 4 1 recognized species in which one or both parents carry the eggs and embryos in the mouth for safety. Substrate-spawning species, of the now restricted genus Tilapia, are not treated here. Three genera of the mouth-brooding species are included though in one of them, Danakilia, the single species is too small to warrant farming. The other two, Sarotherodon, with nine species, and Oreochromis, with thirty-one, are distinguished primarily by their breeding habits and their biogeography, supported by structural features. Each species is described, with its diagnostic features emphasised and illustrated, and to this is added a summary of known ecology and behaviour. Conclusions on relationships involve assessment of parallel and convergent evolution. Dr Trewavas writes with the interests of the fish culturists, as well as those of the taxonomists, very much in mind. 580pp, 188 illustrations include halftones, diagrams, maps and graphs. Extensive bibliography. Publication 1983. 50 565 00878 1 Publications Sales British Museum (Natural History) Cromwell Road London SW7 5BD England Titles to be published in Volume 47 Miscellanea A review of the Mastacembeloidei, a suborder of synbranchiform teleost fishes Part II: Phylogenetic analysis. By Robert A. Travers A review of the anatomy, taxonomy, phylogeny and biogeography of the African neoboline cyprinid fishes. By Gordon J. Howes The haplochromine species (Teleostei, Cichlidae) of the Cunene and certain other Angolan rivers. By Peter Humphry Greenwood Miscellanea Anatomy and evolution of the feeding apparatus in the avian orders Coraciiformes and Piciformes. By P. J. K. Burton A revision of the spider genus Cyrba ( Araneae: Salticidae) with the descriptions of a new presumptive pheromone dispersing organ. By F. R. Wanless Printed in Great Britain by Henry Ling Ltd., at the Dorset Press, Dorchester, Dorset UM 31 Bulletin of the British Museum (Natural History A review of the anatomy, taxonomy, phylogeny and biogeography of the Africai neoboline cyprinid fishes Gordon J. Howes Zoology series Vol 47 No 3 30 August 1984 The Bulletin of the British Museum (Natural History), instituted in 1949, is issued in four scientific series. Botany, Entomology, Geology (incorporating Mineralogy) and Zoology, and an Historical series. Papers in the Bulletin are primarily the results of research carried out on the unique and ever-growing collections of the Museum, both by the scientific staff of the Museum and by specialists from elsewhere who make use of the Museum's resources. Many of the papers are works of reference that will remain indispensable for years to come. Parts are published at irregular intervals as they become ready, each is complete in itself, available separately, and individually priced. Volumes contain about 300 pages and several volumes may appear within a calendar year. Subscriptions may be placed for one or more of the series on either an Annual or Per Volume basis. Prices vary according to the contents of the individual parts. Orders and enquiries should be sent to: Publications Sales, British Museum (Natural History), Cromwell Road, London SW7 5BD, England. World List abbreviation: Bull. Br. Mus. nat. Hist. (Zool.) Trustees of the British Museum (Natural History), 1984 The Zoology Series is edited in the Museum's Department of Zoology Keeper of Zoology : Dr J. G. Sheals Editor of Bulletin : Dr C. R. Curds Assistant Editor : Mr C. G. Ogden ISBN 565 05006 ISSN 0007-1498 Zoology series Vol47 No. 3 pp 151-185 British Museum (Natural History) Cromwell Road London SW7 5BD Issued 30 August 1984 >^W^.-T 3 JA1 ff^^^^^ A review of the anatomy, taxonomy, p|yl6gefl$^$ 34 ] biogeography of the African neoboline cyprinid fishes **^ Gordon J. Howes Department of Zoology, British Museum (Natural History), Cromwell Road, London SW7 5BD Contents Introduction 151 Diagnoses, anatomy and taxonomy of the neoboline genera 152 Neobola .. 152 Chelaethiops 157 Mesobola gen. nov 168 Rastrineobola Phylogenetic relationships of the neoboline group 177 Neoboline distribution and its biogeographic implications 181 Acknowledgements References 1 84 Introduction In a review of the bariliine cyprinids (Howes, 1980), the genus Engraulicypris which previously had contained ten species was recognized as monotypic, its only species, E. sardella confined to Lake Malawi. Those species formerly included in Engraulicypris were re-assigned to the genera Neobola Vinciguerra, Chelaethiops Boulenger, and Rastrineobola Fowler, with the accompanying statement that they formed a monophyletic assemblage whose close relationships were with Asian phoxinines rather than with African bariliines (Howes, 1980: 196). Later, Howes (1983) modified these views and included Neobola, Chelaethiops and Rastrineobola among the bariliines, naming them as the neoboline lineage (see fig. 2 in Howes, 1983). Although a suite of supposed apomorphies characterizing the three genera were given (Howes, 1980: 195), together with lists of their contained species no detailed generic diagnoses were presented. The purposes of this paper are: 1 . To give diagnoses of the genera Neobola, Chelaethiops and Rastrineobola and establish a new genus to contain two species formerly assigned to Neobola. The characters used in these diagnoses are, for the greater part, those involving cranial anatomy. From previous studies (Howes, 1978; 1979; 1980; 1981; 1982; 198 3) and from out-group comparisons made in the course of this work it is clear that in cyprinids cranial characters provide the most pertinent information at all levels of investigation. 2. To review the taxonomy of the included species. Although the neoboline cyprinids are abundant in many lakes and rivers of east, central and west Africa, they are, as compared with other cyprinids poorly represented in collections both in terms of sample sizes and geographic range. The species are small-sized, pelagic zooplanktivores and form an import- ant part of the diet of many piscivores (see Fryer & lies, 1972; Lowe-McConnell, 1975; van Oijen, 1982). Previous taxonomic reviews have been those of Poll (1945) and Whitehead (1 962) but these authors relied for the most part on data compiled from the literature. Almost Bull. Br. Mm. nat. Hist (Zool) 47(3): 151-185 Issued 30 August 1984 151 1 52 GORDON J. HOWES all the material on which this review is based is from the collections in the British Museum (Natural History), and types of nearly all species have been examined. Other specimens used are from the collections of the Central African Museum in Tervuren (MRAC) and the American Museum of Natural History (AMNH). 3. To confirm the supposed monophyly of the neoboline genera and to consider their intra- and interrelationships. 4. To consider, in the light of their phylogenetic relationships, the biogeography of the neoboline taxa and some broader issues of African biogeography. Diagnoses, anatomy and taxonomy of the neoboline genera NEOBOLA Vinciguerra, 1895 Neobola is characterized by the articulation of the lower jaw extending posterior to the centre of the orbit; a dorsally channelled, broad supraethmoid; 10-12 olfactory lamellae on each half of the nasal rosette; 4-7 short gill-rakers on 1st ceratobranchial; small pectoral axial scale with a fleshy ventral border; pharyngeal teeth in two rows, 5-3; scales small with 5-8 parallel radii, 37-41 in the lateral line; the lateral line gently decurved anteriorly and running close to the ventral margin of the trunk with a wave-like irregularity along the caudal peduncle; swimbladder divided by a deep constriction into short anterior and posterior chambers, the posterior extending to above the pelvic fin. CONTAINED SPECIES. N. bottegi, N. Jluviatilis and N. stellae. Cranial anatomy Osteology (Figs 2-4). The ethmo-vomerine bloc is short, deep and triangular, its anterior border has a sloped indentation. The supraethmoid is narrow- waisted, the lateral margins of the bone are concave and raised, thereby forming a shallow dorsal channel; the frontals overlay the posterior border of the bone. The vomer has a concave anterior border which projects only slightly beyond the overlying mesethmoid. Each lateral ethmoid is truncated with the dorsal part of the lateral wall extending anteriorly (Fig. 4). The frontal sensory canal runs along the margin of that bone and is raised above the level of the supraorbital. There are 4 or 5 sensory canal pores; the first is extensive, and all open somewhat laterally. The nasal is long and curved into the concavity of the supraethmoid border; it has no dorsal pores. The infraorbitals are deep (Fig. 6), the sensory canal of the 1st runs along the ventral border of the bone, but in the 2nd, 3rd and 4th the canal runs along the orbital border. In the 5th, the canal passes through the centre of the bone. The supraorbital is broad and long, narrowly separated from the 5th infraorbital. The orbitosphenoids are connected with the parasphenoid via a narrow septum; thepteros- phenoid contacts the ascending process of the parasphenoid across a narrow area of bone. There is a small lateral sphenotic process which provides the greater part of the dilatator fossa. The prootic is large with the anterior trigemino-facialis foramen narrowly separated from its anterior border; there is a long lateral commissure. The posterior myodome is completely floored by the parasphenoid and basioccipital. A small posttemporal fossa is formed by the posterior separation of the dermo and autopterotics. The supraoccipital is small, lacks a crest, and is confined to the posterior slope of the cranium. The jaws are long, the posterior tip of the maxilla extends to, or beyond the centre of the orbit. The maxilla is slender with a low mid-lateral (palatine) ascending process which curved laterally (Fig. 7). The posterior part of the maxilla is spine-like with only a slightly expanded tip which extends to below the centre of the orbit. The premaxilla is slender with a low ascending process and slightly concave ventral border. The dentary is shallow with a long, high, backwardly sloped coronoid process; the dorsal margin of the dentary is gently convex (Fig. 8). The anguloarticular is short with a slightly concave dorsal border. A REVIEW OF THE AFRICAN NEOBOLINE CYPRINID FISHES 153 B Fig. 1 Representatives of neoboline genera: A, Neobola bottegi; B, Mesobola brevianalis; C, Chelaethiops bibie; D, Rastrineobola argentea (drawn from a Lake Kioga specimen). All genera have 7 branched dorsal fin rays (rarely 6 or 8) I 10 pectoral rays; I 7 pelvic rays and 10 + 9 principal caudal rays. Suspensorium (Fig. 9). The hyomandibula is broad and its dorsal facets are deeply separ- ated. There is a weak lateral flange, its recess providing the insertion of the levator arcus palatini muscle. The ento- and metapterygoids have a marked concavity toward the midline; the dorsal border of the entopterygoid is straight, that of the metapterygoid is markedly concave. The palatine is laterally compressed, its anterior head forming a tripartite process, the medial spur of which overlies the concavity between the mid- lateral and anterior ascending maxillary processes. 154 GORDON J. HOWES soc Fig. 2 Crania, in dorsal view: A, Neobola bottegi; B, Chelaethiops elongatus; C, Mesobola brevianalis; D, Rastrineobola argentea. epo = epioccipital; fr = frontal; le = lateral ethmoid; na = nasal; pa = parietal; pte = dermopterotic; soc = supraoccipital; sor = supraorbital. Branchial arches. The ceratobranchials bear 4-8 short gill-rakers. Pharyngeal teeth on the 5th ceratobranchial are caniniform, arranged in two rows (5.3). The operculum (Fig. 9) has a shallow concave posterior border, the ventro-posterior part of the bone being attenuated. A REVIEW OF THE AFRICAN NEOBOLINE CYPRINID FISHES V 155 Fig. 3 Ethmoid region in dorsal view: A, Neobola bottegi; B, Chelaethiops elongatus; C, C. bibie; D, Mesobola brevianalis; E, Rastrineobola argentea; F, Leptocypris niloticus. me = mesethmoid; pe = preethmoid; se = supraethmoid; v = vomer. Scale = 1 mm. Myology (Fig. 13). Section A, of the adductor mandibulae muscle originates from the quadrate and preoperculum. There are two divisions of the section. (1), a triangular anterior part, A,<2, which has an aponeurotic constriction below the anterior border of the eye and is bordered by the ligamentum primordium. This anterior segment continues along the maxilla as a narrow, parallel-fibred element and inserts below the outwardly curved palatine process of the maxilla; (2) a posterior part, A^post, extending from the preoperculum to insert partly on the rictal tissue and partly onto the rim of the dentary coronoid process. Muscle A 2 is thin and narrowly triangular, inserting into an aponeurosis medial to the anguloarticular; a small A w section originates from the aponeurosis. The levator arcus palatini is divided by the sphenotic process and inserts onto the lateral hyomandibular flange. The dilatator operculi is small and broadly triangular, originating from the sphenotic spur and inserting onto the small opercular process. Pectoral girdle (Fig. 10) The upright part of the cleithrum is short, the posterior lamellae lacking any central process; the tip of the horizontal limb extends to a point below the parasphenoid ascending process; the supracleithrum is short, articulating halfway along the cleithral limb; the coracoid is shallow with a fretted anterior border.There is no postcleithrum. Vertebral column The 1st vertebra has a flat articulatory face, it bears short lateral processes that are directed somewhat anteriorly. Centra 2 and 3 are fused and bear long, slightly posteriorly curved lateral processes. The caudal fin skeleton (Fig. 17 A), has 6 hypurals, the 6th being minute. The fused preural and ural centra (PU1+U1) bear a small neural spine; the epural is long and slender; paired uroneurals are lacking. The parhypural bears a short but wide hypurapophysis. Dorsal and ventral procurrent rays are well-developed. 156 GORDON J. HOWES epo exo me le os pts ps pro soc Fig. 4 Crania, in lateral view, (above) Neobola bottegi and (below) Chelaethiops elongatus. bop = basioccipital process; exo = exoccipital; lee = lateral ethmoid extension; os = orbitosphenoid; pro = prootic; ps = parasphenoid; pts = pterosphenoid; other abbreviations as in previous figs. Taxonomy Three species are assigned to Neobola, N. bottegi Vinciguerra, 1895; from the Webei Shebeli and Omo rivers; N. Jluviatilis (Whitehead), 1962 from the Athi and Tana rivers, Kenya and N. stellae (Worth ington), 1932 from Lake Turkana, Kenya. Whitehead (1962) separated Neobola Jluviatilis from N. bottegi on its having fewer lateral line scales and a higher number of branched anal fin rays. However, I find there to be no substantial differences in these features. There are 37-40 lateral line scales in N. bottegi cf. 38-40 in N. Jluviatilis. Anal fin rays range in N. bottegi from 14-18 (N14) cf. 19-21 (N18) in N. Jluviatilis. Gill-raker counts similarly have a continuous range; 5-8 in N. bottegi (7 and 8 in specimens from the Webi Shebeli River and 5-6 in other specimens from other localities listed below) cf 4-6 in N. Jluviatilis. In both species there are 12 nasal lamellae on each half rosette. There are, however, differences in the morphology of the pectoral axial scale, it being smaller and more lobate in N. Jluviatilis than in N. bottegi. Pharyngeal teeth in both species are in 2 rows, 4.3 or 5.3 in N. bottegi and 4.2 in N. Jluviatilis. The total vertebral number for both species is 40 or 41 (4 Weberian+14 abdominal + 2 1-22 caudal + the fused preural and ural centrum). It seems likely that N. Jluviatilis is but the southern population of N. bottegi; further collections from northern Kenya and southern Ethiopia should help resolve this problem. A REVIEW OF THE AFRICAN NEOBOLINE CYPRINID FISHES 157 Fig. 5 Crania, in lateral view, (above) Mesobola brevianalis and (below) Rastrineobola argentea. Neobola stellae (Worthington), 1932 is distinguished from N. bottegi and N. fluviatilis by its small size (maximum adult size measured, 25 mm SL), lower number of olfactory lamellae (10 on each half rosette), lower vertebral number (total, 37 or 38 cf. 40-41) and a small, bluntly triangular pectoral axial scale. There are 28-33 lateral line scales. Worthington (1932) gives a count of 34-37, but in fact none of the types have more than 34 lateral line scales even if one includes scales at the base of the caudal fin. Branched anal fin rays number 12-18. Pharyngeal teeth are in 2 rows, 4.2. SPECIMENS EXAMINED. Neobola bottegi; 1902.11.7:22, Imi, Webi Shebeli; 1905.7.25:94-5, Modjo R.; 1905.7.251:1 10-1 12, Wabbi R.; 1905.7.25:106-9, Iraro R.; 1950.1 1.25:5-6, Webi Shebeli; 1982.5.17:9-14, Webi Shebeli. Neobola fluviatilis; 1961.5.3:1 (holotype); 2-6 (paratypes), Athi R. near Kithimani; 1966.7.5:29^2, Athi R. at Yalta: 1966.8.25:6, Tana R. Neobola stellae; 1932.6.13:57-65 (syntypes); 1932.6.13:47-56, all labelled 'Lake Rudolf; 1973.8.6:65-76, Loiengalani; 1981.12.17:2488-2587, Lodge Spit; 1981.12.17:2173-82, Ferguson's Gulf, Lake Turkana. CHELAETH1OPS Boulenger, 1899 Chelaethiops is characterized by its pointed snout and long, shallow jaws, the articulation of the lower jaw extending posterior to the centre of the eye, a dorsally channelled broad to narrow supraethmoid, laterally opening frontal pores, 16-26 olfactory lamellae on each half rosette, few (5) to many (18) gill-rakers on 1st ceratobranchial, elongate pectoral axial scales, pharyngeal teeth long, recurved in three rows, 5.3.2. Scales with 7-9 widely 158 GORDON J. HOWES Fig. 6 Infraorbital bones: A, Neobola bottegi; B, Chelaethiops bibie\ C, Mesobola brevianalis; D, Rastrineobola argentea. spaced radii, 36-42 lateral line scales; the lateral line gently decurved anteriorly and with a pronounced curve above the pelvic fin base, often with a wave-like irregularity along the caudal peduncle; swimbladder has short anterior and posterior chambers, the posterior extending to above the pelvic fin (exceptionally, long in C. minutus, extending to above the anal fin origin). CONTAINED SPECIES. Chelaethiops elongatus, C. bibie, C. congicus, C. minutus and C. rukwaensis. Cranial anatomy Osteology. The ethmoid bloc is short and deep, its anterior border varies interspecifically from shallow to deeply indented (Fig. 3B & C). The lateral edges of the supraethmoid are A REVIEW OF THE AFRICAN NEOBOLINE CYPRINID FISHES 159 B Fig. 7 Maxillae: A, Neobola bottegi; B, Chelaethiops bibie; C, Neobola stellae; D, Mesobola spinifer; E, M. bredoi; F, M. brevianalis; G, Raster -ineobola argentea. Scales in mm. raised and the width of the dorsal channel is also interspecifically variable. The mesethmoid is deep, its arms widely divergent, abutting on large preethmoids. The vomer floors the mesethmoidal indentation. As in Neobola the lateral ethmoid has an anterior extension of its dorso-lateral wall (lee, Fig. 4). Thefrontals are narrower than those of other neobolines, the sensory canal is more highly developed, and there are 4 large, conspicuous pores all of which open laterally. The nasal is large and reduced to the sensory canal tube with one dorsal pore or none. The infraorbitals more closely resemble those of Neobola than any other neoboline genus, both in their width and orbital configuration. The sensory canal, however, runs along the orbital margin of the bones and the 4th infraorbital is longer than in Neobola (Fig. 6B). The neurocranium is similar to that of Neobola except that the sphenotic has a ven- trally directed process, and there is a ventral opening between the basioccipital and the parasphenoid. The jaws are long (Figs 7 & 8); the maxilla has a low, long palatine process and the bone terminates in a spine-like tip. The upper jaw bones are longer and more slender than those of any neoboline genus. The lower jaw closely resembles that of Neobola except that the symphysial process of the dentary is more prominent and the coronoid process is lower and backwardly sloped at a shallower angle. 160 GORDON J. HOWES cp B Fig. 8 Lower jaw bones: A, Neobola bottegi; B, Mesobola brevianalis; C, Chelaethiops elongatus; D, Rastrineobola argentea; E, Leptocypris niloticus. aa = anguloarticular; cp = coronoid process; ra= retroarticular. The suspensorial bones are like those of Neobola except that the hyomandibula has a pronounced concavity to its lower anterior border and only a slight indentation separates the articulatory condyles. The posterior condyle is shaped into a long, triangular process. The palatine, ecto-, ento- and metapterygoids are all longer than those elements in Neobola and the metapterygoid has only a slight anterior dorsal process (cf. Figs 9A & B). The operculum has a rounded dorsal border and a strongly attentuated, rather triangular lower border (Fig. 9B). Myology (Fig. 13). Muscle adductor mandibulae A, is divided into anterior and posterior segments as in Neobola. The anterior part A^nt, extends from the quadrate to insert below the maxillary cleft. The segment contains an aponeurotic constriction below the anterior border of the eye. The aponeurosis is divided so that the orbital part serves as the site of the attachment for the fibres from the lower part of the muscle, and the outer division is continuous with the ligamentum primordium and serves as the site of attachment for the fibres of the anterior part of that muscle. The posterior segment of muscle A,, A^post, originates from the preoperculum and inserts on to the coronoid process of the dentary and on the rictal tissue. There is no A w section of the adductor mandibulae. The configuration of other jaw and suspensorial muscles are as described for Neobola. Pectoral girdle (Fig. IOC) The pectoral girdle resembles that of Neobola; the coracoid is deeper than in other neobolines and has a markedly fretted antero-ventral margin. There is no postcleithrum. Vertebral column (Fig. 12) The anterior face of the 1st centrum is rounded (cf. flat in Neobola), the centrum bears long lateral processes, the distal tips of which underlie the processes of the fused 2nd and 3rd centra. The lateral processes of the fused centra are curved posteriorly, their distal tips reach- ing to a level with the articulation of the 3rd and 4th centra. The neural complex is upright, the 4th neural spine sloped backward at a low angle (Fig. 12). A large plate-like supraneural, possibly two fused supraneurals, overlies the 4th neural spine and extends backwards to above the 5th; this is followed by 6 or more elements varying in shape from triangular plates to thin rods. The caudal skeleton differs from that of Neobola in elongation of the 6th hypural, the neural spine on the fused preural-ural centrum and the hypurapophysis (Fig. 17B). A REVIEW OF THE AFRICAN NEOBOLINE CYPRINID FISHES hy met pal ent op 161 Fig. 9 Suspensoria in medial view: A, Neobola bottegi; B, Chelaethiops elongatus; C, Mesobola brevianalis; D, Rastrineobola argentea. ect = ectopterygoid; ent = entopterygoid; hy = hyomandi- bula; met = metapterygoid; op = operculum; pal = palatine; po = preoperculum; q = quadrate; sy = symplectic. In Mesobola and Rastrineobola, the symplectic is shown in solid black. Taxonomy Boulenger (1911) included two species in Chelaethiops, viz: elongatus and bibie. Since then only one other species has been described, C. katangae Poll, 1948. Howes (1980) assigned three other species to the genus, Engraulicypris congicus Nichols & Griscom, 1917, Neobola minuta Boulenger, 1906, and Engraulicypris rukwaensis Ricardo, 1939. Chelaethiops elongatus Boulenger, 1899, is characterized by its long and pointed snout and upwardly inclined head (Fig. 19B); a distinct mandibular symphysial notch; 16-17 olfactory lamellae on each half rosette; 5 short gill-rakers on the 1st ceratobranchial; 16-17 branched anal fin rays; 36-38 lateral line scales; axial pectoral scale 30-33% pectoral fin length (Fig. 18C); pectoral fin extending to the origin of the pelvic fin; lower part of posterior opercular border attenuated; pharyngeal teeth in 3 rows, 5.3.2; vertebrae 38 or 39 (4 + 1 1 - 12 + 21 -22 + 1, see p. 156 for method of counting). Distribution of the species is the Zaire drainage. Chelaethiops bibie (Joannis), 1835, is characterized by its narrow supraethmoid with well-developed dorsal channel (Fig. 3C). The snout is pointed but more strongly curved than in C. elongatus and there is a prominent ridge above the eye (Fig. 19 A). There are 12-13 olfactory lamellae on each half rosette; 9 or 10 short gill-rakers on 1st ceratobranchial; 16-17 162 GORDON J. HOWES -scl Fig. 10 Pectoral girdles: A, Neobola bottegi (medial view of disarticulated girdle); B, Mesobola brevianalis; C, Chelaethiops elongatus; D, Rastrineobola argentea (medial views), cl = cleithrum; co = coracoid; mc = mesocoracoid; sca = scaphium; scl = supracleithrum; ptt = posttemporal. bh hb cl Fig. 11 Branchial arches of Mesobola brevianalis. bb = basibranchials; bh-basihyal; C 1 5 = ceratobranchials; eb = epibranchials; hb = hypobranchials; if = infrapharyngobranchials. A REVIEW OF THE AFRICAN NEOBOLINE CYPRINID FISHES 163 vl Fig. 12 Anterior vertebrae, in ventral and lateral views, of Chelaethiops bibie. cla = claustrum; ic = intercalarium; oss = ossa suspensorium; pr = pleural rib; sc = scaphium; sn = supraneurals; tr=tripus; v = vertebrae; vp = lateral vertebral process. branched anal fin rays (rarely 14 or 18); 36-38 lateral line scales; the lateral line usually more irregular and sinuous than that of C. elongatus; axial pectoral scale about 20% of pectoral fin length (Fig. 18E); pectoral fin extending to beyond the origin of the pelvic fin; lower part of the posterior opercular border attenuated; pharyngeal teeth in three rows, variants are 5.3.1. or 4.3.1; vertebrae 36-40 (4+ 1 1 - 13 + 19-22 + 1). Daget (1954) described a subspecies from the Upper Niger which he named as C. elongatus brevianalis. Blache & Miton (1960) decided that Daget's taxon represented a species, which comprised two subspecies, C.b. brevianalis and C.b. lerei from the Mayo Kebbi. It would seem, however, that Daget did not consider C. bibie as he makes no mention of the species in his description. There is no difference between C. bibie and Daget's description of C. elongatus brevianalis. It may well be that Blache & Miton's (1960) taxon from the Mayo Kebbi represents a subspecies, or morphologically distinct population, but this fact has yet to be established. There are differences in vertebral counts between Nilotic C. bibie and those from Ghana as follow: Nilotic specimens; 12 or 13 abdominal and 22 caudal, Ghanian specimens; 1 1 or 12 abdominal and 19 or 20 caudal. Chelaethiops bibie occurs in the Nile (including Lake Turkana), Niger (eastern limit uncertain) and Volta. Chelaethiops minutus (Boulenger), 1906, is characterized by its narrow supraethmoid with well-developed dorsal channel; long and downwardly curved snout, its tip extending beyond that of the lower jaw (Fig. 19E); a prominent frontal ridge above the orbit; 25-27 olfactory lamellae on each half rosette; 17 or 18 long gill-rakers on the 1st ceratobranchial; 18-21 branched anal fin rays; 39-42 lateral line scales; axial pectoral scale 22-25% pectoral fin length (Fig. 1 8G); pectoral fin not reaching beyond the origin of the pelvic fin; posterior border of the operculum rounded; pharyngeal teeth in 3 rows, 5.3.2; vertebrae 39 or 40 (4+12-13 + 22-23 + 1). This species differs from other Chelaethiops in gill-raker length and number, an elongate posterior chamber of the swimbladder extending to, or just beyond, the anal fin origin and 164 GORDON J. HOWES A i post Fig. 13 Jaw muscles of (above) Neobola bottegi and (below) Chelaethiops elongatus. A = divisions of the adductor mandibulae muscle; 1 p = ligamentum primordium; lap = levator arcus palatini; the vertical line marks the orbital centre. the articulation of the anterior 3 or 4 supraneural bones. It is endemic to Lake Tanganyika (see Poll, 1953). Chelaethiops congicus (Nichols & Griscom), 1917, is characterized by its short and blunt snout (Fig. 19C); broad supraethmoid with shallow dorsal channel; 12-15 olfactory lamellae in each half rosette; 5-6 short gill-rakers on the 1st ceratobranchial; 16-18 branched anal fin rays; 38-42 lateral line scales; axial pectoral scale 30-33% pectoral fin length (Fig. 18F); pectoral fin extending to the origin of the pelvic fin; upper part of posterior opercular border concave; pharyngeal teeth in 3 rows, 5.4.1 or 5.3.1; vertebrae 41 (4+ 14 + 22 + 1). It appears that although authors have cited C. congicus in their comparative analyses, none has actually examined the type specimens (Poll, 1945; Whitehead, 1962; Ricardo, A REVIEW OF THE AFRICAN NEOBOLINE CYPRINID FISHES 165 Fig. 14 Jaw muscles of (above) Mesobola brevianalis and (below) Rastrineobola argentea. A, lateral and B, medial views. 1939). Poll (1948) described Chelaethiops katangae from the Lufira, Zaire. Poll did not, however, compare his specimens with C. congicus but only with C. elongatus and C. bibie. I find the holotype of C. congicus to be closely similar to the syntypes of C. katangae in all morphological aspects and consider C. katangae to be a synonym of C. congicus. The distribution of C. congicus is the Zaire basin. Chelaethiops rukwaensis (Ricardo), 1939, is characterized by its narrow supraethmoid with well-developed dorsal channel; pointed and curved snout (Fig. 19D); 16-17 olfactory lamellae in each half rosette; 5-6 short gill-rakers on the 1st ceratobranchial; 15-17 branched anal fin rays; 36-38 lateral scales; axial pectoral scale with wavy border (Fig. 18F), 20-25% pectoral fin length; pectoral fin extending to the origin of the pelvic fin; upper posterior border of the operculum shallowly concave, lower border slightly attenuated; pharyngeal teeth in 3 rows, 5.3.1; vertebrae 38^0 (4 + 14-16 + 19 + 1). 166 GORDON J. HOWES A] post Fig. 15 Jaw muscles of (above) Leptocypris niloticus and (below) Raiamas senegalensis. Ricardo (1939) described, from Lake Rukwa, a subspecies of Chelaethiops congicus, commenting: 'It is ... thought best to regard the examples from L. Rukwa as a new subspecies of E. congicus in order to show that they do differ from all forms previously known and that they are more closely related to the Engraulicypris in L. Tanganyika and the Congo than to any of the species found in other lakes or rivers.' From this statement it would seem that Ricardo was regarding the subspecies as a convenience category to demonstrate her opinion of relationship. The comparative material from Lake Tanganyika and the Congo used by Ricardo is in fact composite. The speci- mens from the Congo are those included herein under C. congicus, but those from Lake Tanganyika differ in morphometric and other characters and, in these respects, are closer to the samples from Lake Rukwa. As with the Lake Rukwa specimens, the Lake Tanganyika sample has a pectoral axial scale length of 20-25% the pectoral length, cf. 30-33% in C. A REVIEW OF THE AFRICAN NEOBOLINE CYPRINID FISHES 167 Fig. 16 Jaw muscles of Engraulicypris sardella. congicus, 16-18 olfactory lamellae, cf. 12-15 in C. congicus, and 36-38 lateral line scales, cf. 38-42 in C. congicus. There is an added difficulty concerning the exact provenance of the 'Lake Tanganyika' sample of C. rukwaensis. Neither Poll (1953) nor Brichard (1978) in their respective accounts of Lake Tanganyika fishes record any species of Chelaethiops (their Engraudicypris) other than C. minutus. The record of Lake Tanganyika C. congicus given by Ricardo (1939) is based on the material collected by Christy. No more precise locality is available than 'L. Tanganyika' and it may well be that the specimens were collected in the environs of the lake. Howes (1980) noted that C. rukwaensis was most closely related to an undescribed taxon from Lake Tanganyika. The taxon is the 'L. Tanganyika' sample discussed above. The status of the taxon is difficult to determine on the basis of such a small sample (55 specimens) and with imprecise locality data. It is further complicated by specimens from the Luiche river, Malagarasi system, having characters intermediate between the C. rukwaensis and C. congicus (viz: 38 lateral line scales, 14 branched anal fin rays and 12 olfactory lamellae on each half rosette). The 'L. Tanganyika'- Malagarasi forms may eventually prove to be a morphologically distinct local population (or subspecies) but for the present my study material is identified only as 'Chelaethiops rukwaensis'. SPECIMENS EXAMINED. Chelaethiops elongatus: 1901.12.26:31, Banzyville Ubanghi; 1912.12.6:9-10, Dungu, Uelle; 1919.9.10.241-2, Avakubi, Ituri; 1920.7.12:39^0, Banghi; 1975.6.20:308-40. 34-43, 344-47, Lualaba; 348-49, Ituri Bridge; MRAC 85848-947, Ankoro, Lualaba. Chelaethiops bibie. Nile: 1904.9.26:22-23. Kalioub, north of Cairo; 1907.13.2:1513-9, near Luxor; 1520-23, between Luxor and Asswan; 1524, Asswan; 1525, Kermeh, Nubia; 1526- 1626. Omdurman; 1627, White Nile; 1628-31, Lake No; 1632-51, 52-53, Gondokoro; 1913.11.11:5-7; Khor Barboy; 1924.5.21:1-5, near Cairo; 1981.2.17:1314-1358. Tode- nyang, L. Turkana; 1369-1431, Morago R., Turkana; 2378-2427, west shore, L. Turkana; 2428-2437, Ferguson's Gulf, L. Turkana. West Africa: 1935.5.29:9-18, Kaduna, Nigeria; 1969.11.14:109-23, Volta, Ghana; 1974.1.2:185, Black Volta; 1982.4.13:783-93, Bahindi, Nigeria; 794-797, Sokoto R., 821-830, Sokoto-Rima floodplain; 799-811, 812-820, Rima R., N. Nigeria. Chelaethiops minutus: 1906.9.8:55-60 (syntypes), Mbete (14-24 mm SL); 1955.12.20:1021- 1029, L. Tanganyika (54-66 mm SL); 1982.9.24:61-66, Kigoma (67-5-86-5 mm SL). 168 GORDON J. HOWES -pr ep Fig. 17 Caudal fin skeletons: A, Neobola bottegi; B, Chelaethiops elongatus; C, Mesobola brevianalis; D, Rastrineobola argentea. cpu = fused preural-ural centrum; ep = epural; h6 = 6th hypural; hp = hypurapophysis; ph = parhypural; pr = procurrent rays. Chelaethiops congicus; AMNH 6295 (holotype), Poko, Ubangi; MRAC 78108-9 (syntypes of C. katangae), Kafila, Lufira; BMNH 1919.9.10:238, Avakubi, Ituri; 1919.9.10:239, Busabangi, Lindi; 1902.4.14:47-8, Lindi R.; 1907.4.30:42, Atuwimi R.; 1909.7.9:62, Bumba (Boumba) R., Assobam, S. Cameroon; 1975.6.20:350-402, Lufira R. Chelaethiops rukwaensis; 1942. 12.31.: 19 1-2 10 (syntypes), Lake Rukwa; 1936.6.15:547-67, 'L. Tanganyika'; 1969.1.31:49-105, Lake Rukwa; 1971.6.22:137-138, Luiche R., Malagarasi system. MESOBOLA gen. nov. TYPE SPECIES. Engraulicypris brevianalis Boulenger, 1908, Ann. Natal M us. 1: 231 This genus is uniquely denned by its cranial, jaw bone and jaw muscle morphology. At the same time it can be included with Neobola, Chelaethiops and Rastrineobola on the basis of those synapomorphies denning the neoboline group (p. 177). Mesobola is characterized by a narrow, dorsally channelled supraethmoid; vomer forming a floor to the ethmoid inden- tation; pre-ethmoids directed rostrad; nasal without dorsal pores; frontal canal with 4 or 5 pores; narrow, triangular metapterygoid process; symplectic elongate with expanded tips; A REVIEW OF THE AFRICAN NEOBOLINE CYPRINID FISHES 169 Fig. 18 Pectoral axial scales: A, Neobola bottegi; B, Neobola stellae; C, Chelaethiops elongatus; D, C. rukwaensis; E, C. bibie; F, C. congicus; G, C. minutus. 8-10 olfactory lamellae on each half rosette; pectoral axial scale absent; pharyngeal teeth in 3 rows; swimbladder with long anterior and posterior chambers, the posterior curved downward and terminating above the anus. CONTAINED SPECIES. M. brevianalis, M. spinifer, M. bredoi and M. moeruensis. Cranial anatomy Osteology. The most characteristic feature of the cranium is the morphology of the ethmoid region (Fig. 3D). The ethmoid bloc is hour-glass shaped, the supraethmoid with a deep anterior notch, its lateral walls lamellate and forming a deep channel posterior to the notch. The mesethmoid has a V-shaped anterior indentation, the preethmoids being situated on the tips of the mesethmoid arms and thus considerably extending the depth of the indentation. The vomer floors the notch and where it meets the preethmoids there is a thickening of the bone, thus forming what appears to be medial processes of the preethmoids. In some specimens there is a small vomerine foramen. The lateral ethmoid margin curves antero-ventrally and lacks the dorsal lamellae present in Neobola and Chelaethiops. The frontal canal (Fig. 2C) lies close to the edge of that bone and has 4-5 pores. The size and position of the canal pores is interspecifically variable, but the posterior pore always opens laterally. The nasal is large, lacking dorsal pores. The cranial roof is convex in the area of the fronto-parietal suture; in all other neoboline genera the roof is flat. The infraorbitals (Fig. 6C) are shallow, as in Rastrineobola (cf. deep in Neobola and Chelaethiops). The infraorbital canal runs along the ventral part of the 1st bone, the orbital border of the 2nd and through the centres of the 3rd, 4th and 5th infraorbitals. The orbitosphenoids are connected to the parasphenoid via a deep, narrow septum. The anterior trigemino-facialis foramen indents the border of the prootic and there is a long lateral commissure (Fig. 5). There is a small foramen between the parasphenoid and basioccipital. 1 70 GORDON J. HOWES The jaws are long (Figs 7 & 8); the palatine process of the maxilla varies interspecifically from being low and long, to high and triangular in shape (see p. 180 & Figs 7D-F). The articulation of the dentary with the quadrate is below the centre of the orbit. The dentary is rather deep with a convex dorsal border and a backwardly sloped coronoid process. The anguloarticular has a long, almost horizontal dorsal border. The suspensorium (Fig. 9C). The hyomandibula is narrow with a straight anterior border. The dorsal border is sloped so that the anterior articulatory condyle is at a level lower than that of the posterior condyle. The ento- and metapterygoids are deeper than those of other genera. The entopterygoid is long with a slightly concave dorsal border; the metapterygoid has a narrow, triangular anterior process directed mesad. The most noticeable feature of the suspensorial elements is the length and shape of the symplectic. The bone is excessively elongate with expanded tips where it contacts the quadrate and the hyomandibula. Branchial arches (Fig. 11). The ceratobranchials bear 7-12 long gill-rakers, pharyngeal teeth are arranged in 3 rows with interspecific variation of 4.2.1, 4.3.1 and 5.3.2. The operculum has a concave upper posterior border and an attentuated lower part (Fig. 9C). Myology (Fig. 14). As in Neobola and Chelaethiops, section A, of the adductor mandibulae muscle is divided, but A. { ant lacks the aponeurotic constriction present in those two genera and extends from the quadrate to insert below the anterior cleft of the maxilla. Muscle A, post extends from the lower limb of the preoperculum to insert partly on the coronoid process of the dentary and partly, via a long tendon, into the fascia of \ { ant. Other muscles are arranged as in Neobola. Pectoral girdle (Fig. 1 0) The upright part of the cleithrum is narrower than in Neobola and more closely resembles that of Chelaethiops in shape; the coracoid is deep and its posterior border forms a sharp angle with the ventral border. There is no postcleithrum. Vertebral column The 1st vertebra has a flat anterior face, and short, blunt lateral processes. The 2nd and 3rd centra are fused, bearing long, lateral processes with posteriorly curved tips. The caudal fin skeleton closely resembles that of Neobola in having a small 6th hypural and reduced spine on the fused ural centrum, and short hypurapophysis (Fig. 17C). There are no paired uroneurals. Dorsal and ventral procurrent rays are well-developed. Taxonomy Mesobola brevianalis (Boulenger), 1908, is characterized by a maxilla with a high, narrowly triangular mid-lateral (palatine) ascending process (Fig. 7F); 10 olfactory lamellae on each half rosette; absence of pectoral axial scales; 12-15 branched anal fin rays (12 in the type specimen, 14-15 in others); 9-12 gill-rakers on 1st ceratobranchial; 48-50 lateral line scales, the lateral line with a pronounced and abrupt downward curve over the pectoral fin, and another at the caudal fin base; pectoral fin reaching to origin of the pelvic; pharyngeal teeth in 3 rows, interspecific variation, 4.2.1-5.3.2; swimbladder with long anterior and posterior chambers, the posterior curving downward and terminating above the anus; vertebrae 39 or 40 (40+ 13 -14 + 20-22 + 1). Jubb (1967) gives a description, synonymy and distribution for the species. Bell-Cross (1956a) records M. brevianalis from the Kabompo river and an 'isolated' example from Fort Rosebery, off the Luapula river. Jubb (1967) refers to M. brevianalis from the Cunene river, although this species is not listed by Bell-Cross (19656) in his check-list of the fishes of that river. The species is recorded from Zambia, Zimbabwe, Transvaal and Natal. On the western side of South Africa, it occurs below the Aughrabies Falls of the Orange river (Jubb, 1967:127). A REVIEW OF THE AFRICAN NEOBOLINE CYPRINID FISHES 171 Fig. 19 Characteristics of Chelaethiops species: A, C. bibie\ B, C. elongatus; C, C. congicus; D, C. rukwaensis; E, C. minutus. The arrows indicate specific features; length and shape of snout, inclination of head, prominence of frontal ridge, shape of opercular border. Mesobola bredoi (Poll), 1945, is characterized by a maxilla with a high and narrowly triangu- lar palatine process (Fig. 7E); low number of olfactory lamellae, 8 on each half rosette; 1 1-13 anal fin rays; lateral line scales 36-39; 12 long gill-rakers; pharyngeal tooth formula: 4.2.1; vertebral number 37-39 (4+12 13 + 19 21 + 1). The species is confined to Lake Albert. Mesobola moeruensis (Boulenger), 1915, is characterized by a maxilla with a low, sloped palatine process; 9 long gill-rakers; the lower posterior border of the operculum attenuated; 8 olfactory lamellae on each half rosette; 1 5 branched anal fin rays; lateral line scales 4 1 ; pharyngeal tooth formula, unknown; vertebral number 38 (4+12 + 21 + 1). All characters taken from a syntype. A sample of 10 specimens from Katanga (MRAC 85812-847) named as this species, have gill-rakers less spinose than those of the type specimen and more closely resembles M. spinifer. Mesobola moeruensis is most probably confined to Lake Mweru, and those samples from elsewhere named as this species belong to some other taxon. 172 GORDON J. HOWES 4-6 8-11 Fig. 20 Above, synapomorphy scheme of the neoboline group. Synapomorphies are, I , chan- nelled supraethmoid; 2, frontal canals at edge of the bones with extensive, laterally opening pores; 3, divided A, muscle with complex aponeurotic inclusions; 4, derived ethmovomerine morphology; 5, elongate symplectic; 6, derived jaw morphology; 7, forward shift of jaw articula- tion; 8, anterior extension of lateral ethmoid; 9, aponeurotic constriction of muscle A,an/; 10, enlarged frontal pores; 1 1, hypertrophied supraneurals; 12, divided A, aponeurosis (see text, pp. 179). Below, cladogram showing relationships of the neoboline group. Synapomorphies are, 1, divided A, muscle; 2, pectoral axial scales (secondarily lost in some taxa); 3, A, post muscle insertion divided; 4, derived ethmovomerine morphology (see text, pp. 181). A REVIEW OF THE AFRICAN NEOBOLINE CYPRINID FISHES 173 Mesobola spinifer (Bailey & Matthes), 197 1 , is characterized by a maxilla with a low, sloped palatine process (as in M. moeruensis)', 7-8 olfactory lamellae on each half rosette; 9-1 1 gill-rakers on 1st ceratobranchial; 15-16 branched anal fin rays; lateral line scales, 41-45; pharyngeal tooth formula, 4.3.2.; vertebral number 39-41 (4+13 + 21 -23 + 1). Bailey & Matthes (1971) compare M. spinifer with other species here included in Neobola and Mesobola and conclude that it is most closely related to M. moeruensis. They distinguish spinifer from moeruensis principally on the higher number of gill-rakers. However, in the syntype of M. moeruensis I count 9 rakers on the ceratobranchial, not 7-8 as given by Bailey & Matthes. There is no substantial difference in lateral line scales and branched anal fin ray counts. Bailey & Matthes (1971) also distinguish M. spinifer from M. moeruensis on body depth. The authors give a body depth range of 18-3-2 1-8% of SL for M. spinifer but give no figures for M. moeruensis. The body depth for the only examined syntype is 22-8% of the SL and the range for the Katangan specimens of 'moeruensis ' (see above) is 21 -1-24-7% (mean 23-5%). In numbers of branched fin anal fin rays (16-18) and vertebral count (total 39-40), the Katangan specimens of M 'moeruensis' are closer to M. spinifer than to the type specimen of M. moeruensis. Mesobola spinifer occurs in the Malagarasi and Ruaha drainages (see Bailey & Matthes, 1971). SPECIMENS EXAMINED. Mesobola brevianalis: 1907.4.17:90 (holotype), Mkuzi R., Zululand; 1907.5.15:5-7, Devaard R., Transvaal; 1915.6.29:15-17, Aapies R., at Petronella; 1977.6.27:299-300, Namaini Pan, Pongolo R.; 1977.6.27:307-1256, Pongolo R., below Jazini Dam, Mzinyeni Pan, N. Natal; 1982.4.13:4693-97, Sabe R., Chisumbanje, Zim- babwe; 1978.8.3:158-62, L. Chiuta; MRAC 186489-947, Chambesi R., Rhodesia. Mesobola bredoi: 1969.3.18:1-15, Lake Albert. Mesobola moeruensis, 1920.5.26:84 (syntype), Lake Mweru; Mesobola 'moeruensis ' MRAC 85812-847, Elizabeth ville, Katanga. Mesobola spinifer. 1970.3.10:1 (holotype), Kazima, Malagarasi watershed; 1970.3.10:2-9; 10-11 (paratypes), same locality as holotype. RASTRINEOBOLA Fowler, 1936 Rastrineobola argentea (Pellegrin), 1904 is the type and only species of the genus. It is characterized by an elongate ethmoid region, short, deep jaws, long gill-rakers, 10 olfactory lamellae on each half rosette, absence of pectoral axial scale and a swimbladder with long anterior and posterior chambers, the posterior curving downward and extending to above the anus. Cranial anatomy Osteology (Figs 2, 3 & 5). The ethmoid bloc is long, narrow and deep. The lateral edges of the supraethmoid are raised forming a shallow dorsal channel; posteriorly the bone is overlapped by the frontals. The mesethmoid has an omega-shaped (ft) indentation, the lateral arms abut on long, anteriorly directed preethmoids. The vomer floors the mesethmoid indentation and its anterior border is also strongly indented. The exposed portion of the vomer, between the mesethmoid arms, is sometimes perforated (Fig. 3E). The lateral ethmoid has a marked lateral protrusion (cf. the truncated condition in Neobola and Chelaethiops) from the frontal margin and is sloped anteroventrally. The frontal canal in common with other neobolines lies on the margin of the bone and has 3 dorsally directed sensory pores; the 4th pore opens laterally. The nasal is broad, lacking dorsal pores. The morphology of the neurocranium is essentially like that of Mesobola except in having a flatter cranial surface, smaller sphenotic, straighter edged pterotic, longer basioccipital and parietals. The supraoccipital is also shorter than in Mesobola and bears a slight crest (Fig. 5). There is a ventral opening between the basioccipital and parasphenoid. 174 GORDON J. HOWES Fig. 21 Distribution of Neobola and Chelaethiops. The single dashed line indicates the probable limit of Neobola distribution; the area enclosed by the dotted line is devoid of any records of Neobola species. The Nile marks the eastern boundary of Chelaethiops, that in the west is unknown and is indicated as the Volta, the northern extent is marked by a double-dashed line. The lakes where Chelaethiops species occur are shown in solid black. The infraorbitals (Fig. 6D) are all of approximately the same depth, the 1st is broadly triangular with the sensory canal passing through its centre, the 2nd bears an antero-dorsal process and the canal, as in the 3rd, 4th and 5th, runs through the centre of the bone. The 5th infraorbital is separated from the wide supraorbital. The jaws (Figs 7 & 8) are shorter than in other neobolines. The maxilla bears a high mid- lateral (palatine) ascending process with a convex (cf. concave) posterior border (Fig. 7G). A REVIEW OF THE AFRICAN NEOBOLINE CYPRINID FISHES 175 Fig. 22 Distribution ofMesobola, Rastrineobola, Leptocypris and Engraulicypris. The supposed limits of Mesobola species are indicated by hatched lines, the lakes where they occur by solid black. Exclamation signs mark the western records. The Nile is the eastern boundary of Leptocypris, while the dotted lines indicate the supposed northern and southern boundaries. Rastrineobola occurs only in Lakes Victoria and Kioga, and Engraulicypris in Lake Malawi. Anteriorly the maxilla is not bifurcated as in the other genera where the arms of the bifurca- tion are of equal length. Instead the medial arm is the longer and is directed ventrally. The ventral border of the maxilla is concave. The premaxilla has a short anterior ascending process. The dentary is deep with a convex dorsal border and a high, rounded coronoid process, halfway along the bone. The anguloarticular is long with a horizontal dorsal surface (Fig. 8D). Suspensorium (Fig. 9D). The hyomandibula is broadly triangular, its anterior edge vertical; the articulatory condyles are widely separated, the intervening border of the bone being gently concave. The metapterygoid bears a well-developed, narrow process which is directed medially and overlies the posterior margin of the entopterygoid. The ectopterygoid 1 76 GORDON J. HOWES is a short, deep bone (cf. long and slender in other neobolines). As in Mesobola, the symplectic is elongate with expanded tips and extends the length of the metapterygoid. Branchial arches. The ceratobranchials are short with 12 or 13 long gill-rakers; epi- branchials with 3 or 4; pharyngeal teeth long and recurved, in 3 rows, 4.3.2. Infrapharyngo- branchial 2 is short and almost square, compared with a longer, triangular element in other neobolines. The operculum (Fig. 9D) is long with a sloped and rounded posterior border. Myology (Fig. 14). As in Mesobola, the adductor mandibulae section A, is divided, the anterior part, A, ant, originating from the quadrate and inserting musculosly on to the anterior part of the maxilla; the posterior part, A t post, originates from the preoperculum to insert in part via a long tendon into the medial fascia of A, ant and in part on to the dorsal rim of the coronoid process of the dentary. Muscle A 2 originates from preoperculum and is divided by the levator arcus palatini. The muscle inserts via a long tendon on to the medial face of the anguloarticular; a small segment of muscle runs from the tendon of A 2 to the medial rim of the coronoid process, this segment is taken to represent A w (Fig. 14B). Pectoral girdle (Fig. 10D) The upright part of the cleithrum is short, the tip of the horizontal limb extending to a point below the parasphenoid ascending process. There is a longer upright cleithral lamina than in other neobolines. The coracoid is deeper posteriorly than in any other neoboline and has an irregularly shaped posterior border; there is also a slight fretting of the anteroventral margin in some specimens. Vertebral column The 1st centrum has a flat articulatory face and long lateral processes; the 2nd and 3rd centra are fused with long, recurved lateral processes. There are 38-40 vertebrae (4+16+17 + 19 + 1). The caudal skeleton (Fig. 17D) more closely resembles that ofChelaethiops in having a long 6th hypural; it differs from other neobolines in possessing a bifurcate or trifurcate spine on the fused ural centrum, a bowed epural and anteriorly expanded neural spine on the 1st preural centrum. There is a long hypurapophysis. Taxonomy There is a considerable variation in lateral line scale counts in the several samples examined. Also, there is a higher range of branched anal fin rays in a sample from Lake Kioga than in those from Lake Victoria. The compared samples are, however, small and it is possible that there may be a greater overlap of minimum values than those indicated: LOCALITY N SL RANGE (MM) SCALES IN LL. MEAN ANAL RAYS Mwanza 51 49-0-70-0 42-56 50 12-14 Entebbe 20 38-5-78-7 44-56 49 12-14 Lake Kioga 13 38-0-52-6 40-54 49 14-16 In the sample from Entebbe the largest specimen examined, 78-7 mm SL, has 51 scales compared with 56 in a specimen 52-5 mm SL. SPECIMENS EXAMINED. L. Victoria: 1905.2.28:2-8 (syntypes), Kavirondo Bay; 1906.5.30:146-51, Bunjako; 1908.10.19:8, Sesse Island; 1909.7.27:11, Kavirondo Bay; 1909.11.15:20, Kizumu Bay; 1964.2.20:12-18, Entebbe; 1982.9.24:1-10; 41-50, Entebbe; 1982.9.24:31-40, Katebo; 1982.9.24:11-20, Mwanza; 50 specimens measured at Mwanza but not preserved. Lake Kioga: 1929.4.16:21-22; 1939.3.8:1-10; 1982.9.24:21-30; 1982.9.24:51-60. A REVIEW OF THE AFRICAN NEOBOLINE CYPRINID FISHES 177 Asia V .Q-Za-G-Zi. N N-Za-G-Zi. Za-G. N-Ec-Zi Fig. 23 Reduced area cladogram of African bariliines and neobolines. a = Opsaridium + Asian bariliines; b = Raiamas; c = Leptocypris + Engraulicypris; d = Chelaethiops; e = other neoboline genera. EC = East Coast; G = Guinean; N = Nilo-Sudanian; Q = Quanzan; Za = Zairean; Zi = Zambesian. Phylogenetic relationships of the neoboline group Monophyly The assumed monophyly of Neobola, Chelathiops, Mesobola and Rastrineobola is based on the following synapomorphies: 1. Ethmovomerine morphology. The supraethmoid in all neobolines is narrow and dorsally channelled (see p. 1 52). The plesiomorphic cyprinid supraethmoid is broad and flat (see Howes, 1981). Within the neobolines, the most extreme form of supraethmoid channelling occurs in Mesobola (Fig. 3D). The width and development of the dorsal channel varies interspecifically in Chelaethiops (Figs 3B & C). In Neobola the dorsal channel is least developed. Howes (1979) argues that the overlap of the supraethmoid by the frontals is a synapomor- phy for chelines and possibly Chelaethiops (Engraulicypris of Howes, 1979). However, further study shows a similar condition in several other cyprinid taxa, usually in juveniles, where it is an ontogenetic precursor to the sutured joint of the adult. Where it survives in adults, it must be looked upon as ontogenetic retention and therefore plesiomorphic. 2. The frontal canals situated at the edge of the bone. Frontal canals occupy the border of the bone only in neobolines. The sensory canal openings are few (3-5), of large aperture, and in Neobola and Chelaethiops alone all open laterally (Fig. 2). The common condition in cyprinids is for the frontal sensory canals to be embedded within the bone, distant from its margin and with small dorsal pores. See Howes, 1981 : 17-18 for an account of the plesiomorphic cyprinid frontal. 3. A derived jaw muscle morphology. In all neobolines, the adductor mandibulae A, section is divided into anterior (A,a0 and posterior (A^post) segments. A^nt originates from the quadrate and inserts on the maxilla; A,/?as/ originates from the lower part of the preoperculum and inserts variously into the lower jaw bone and rictal tissue (see below). 178 GORDON J. HOWES Zairean L. Rukwa LTang'ka Zairean Nilotic congicus rukwaensis minutus elongatus bibie Fig. 24 Cladogram of Chelaethiops species. Synapomorphies are 1, A. { post inserts entirely into the dorsal aponeurosis of A. l ant, well-developed frontal canal openings; 2, ethmoid region elongated, dentary with convex margin, articular face of 1st centrum prominently rounded, maxillary valve of increased width; 3, highly developed aponeurotic connection between A { ant and A. t post, elongate axial scales. The plesiomorphic cyprinid condition of the adductor mandibulae A, is an undivided element with a simple insertion on the maxilla (see Takahasi, 1925; Howes, 1982 : 31 1). The only other cyprinids known to possess a divided A, are certain bariliines (see below). Another, assumed, synapomorphy is the loss of the single pair of uroneurals in the caudal skeleton. All neoboline genera lack these elements that are present in all other cyprinid taxa examined or documented; the only known exception is Engraulicypris sardella. It would appear that several sets of uroneurals is a primitive teleost character (see Patterson, 1968). Amongst other otophysans, characoids have up to 3 pairs, and in siluriformes, they are consolidated with other elements of the caudal skeleton (see Fink & Fink, 1981). In those cyprinid genera considered to be plesiomorphic (Opsariichthys, Opsaridium, Barilius), the paired uroneurals are elongate bones extending to the base of the 5th hypural. In the majority of cyprinid taxa the bones are short, triangular or curved elements. On grounds of commonality amongst cyprinids, the loss of paired uroneurals in neobolines should probably be looked upon as a synapomorphy. Relationships of neoboline genera A series of further derived states of those synapomorphies listed above together with other derived features relate the neoboline genera in the following pattern: Neobola and Chelaethiops share: 1. A derived form of the lateral ethmoid. The dorsal part of the outer wall of the lateral ethmoid is produced anteriorly as a 'shield' covering the posterior portion of the olfactory A REVIEW OF THE AFRICAN NEOBOLINE CYPRINID FISHES 179 Asia N-Ec-Zi-Q Fig. 25 Reduced area cladograms of (above) Vari's (1979) scheme of distichodontid and cithari- nid relationships; a-f indicate a = Citharinidae, b = Distichodontidae, Vari's (fig. 47) genera D-E; c genera G-I; d = genera J-Q; e = Paradistichodus; f=Xenocharax; (below) Parenti's (1981) scheme for Old-World aplocheiloids, another aplocheiloids; b = Aphyosemion. Area abbrevia- tions are as in Fig. 23. organ (see p. 152 & Fig. 4). Elsewhere amongst cyprinids this condition is known only in Salmostoma, but here it is the entire lateral ethmoid wall, rather than just the dorsal part, that extends forward. This is probably a parallelism with neobolines in view of the opposing synapomorphy scheme of Salmostoma among chelines (see Howes, 1979; 1983). 2. An aponeurotic constriction of muscle segment A { ant. This configuration of the muscle may be a mechanical device allowing A, to circumvent the eye. Otten (1981) presents a diagram hypothesising the functional advantage of A, having an aponeurotic sheet in just such a position as occurs in Neobola and Chelaethiops. In Chelaethiops there is a further derived state whereby the aponeurosis is bifurcated. 3. Enlarged frontal pores opening laterally. Those in Chelaethiops are all laterally directed and the frontal canal is raised above the level of the supraorbital so forming a pronounced ridge in some species (Fig. 19). 4. Hypertrophied supraneurals. The supraneurals are plate-like elements. In Chela- ethiops the bones are larger than in Neobola, their most extreme form is encountered in Chelaethiops minutus where the anterior 3 or 4 are articulated in a similar fashion to those in some chelines (see Howes, 1979). The presence in Chelaethiops of a condylar face on the 1st centrum suggests the facility of cranial elevation, again as in chelines. 180 GORDON J. HOWES Mesobola and Rastrineobola share: 1. A derived ethmovomerine morphology. Mesobola and Rastrineobola both have a deep mesethmoid indentation which in Mesobola is V-shaped and in Rastrineobola omega-shaped (see p. 173). In both genera the arms of the mesethmoid abut on long, anteriorly directed preethmoids which, in effect, extend the depth of the indentation. The mesethmoid inden- tation is floored by the vomer which in both genera is often perforated, the foramen may be small or may coincide with the rim of the overlying mesethmoid. There are also dorsal protruberances of the vomer on either side of the medial notch (Figs 3D & E). 2. An elongate symplectic. The cyprinid symplectic is usually a near-triangular bone (the base of the triangle abutting on the lower tip of the hyomandibula). This form of symplectic occurs in Neobola and Chelaethiops (Figs 9A & B), but in Mesobola and Rastrineobola, the bone is elongate and horizontal rather than forming the usual steep angle (Figs 9C & D). The tips of the symplectic are spatulate. 3. A derived jaw morphology. The maxilla in Mesobola and Rastrineobola has a tall mid-lateral (palatine) ascending process. In this respect the form of the maxilla is near to that postulated for the presumed plesiomorphic cyprinid type (see Howes, 1981: 28). That this is a secondarily derived form in Mesobola and Rastrineobola is suggested by the following observations: (i) In Chelaethiops and Neobola, the sister-taxa to Mesobola and Rastrineobola, the upper jaw bones are long and slender; the maxilla having a long, low palatine process. This is the characteristic morphology for all bariliines and chelines, considered as the close relatives of the neobolines (see below); (ii) There is a marked concavity of the posterior border of the palatine process, and an acute lateral curvature. These features are absent in plesiomorphic cyprinid maxillae, but present in bariliine and cheline taxa; (iii) The presence of a transitional sequence in Mesobola species. In M. spinifer the palatine process is long and low, but even so is still higher than that of Neobola, Chelaeth- iops and bariliines. In Mesobola brevianalis and M. moeruensis, the process is taller and more triangular, and in Rastrineobola, the palatine process is best developed (Figs 9D-G). In Mesobola and Rastrineobola the dentary is deep with a convex dorsal border, a feature particularly marked in Rastrineobola (Fig. 8E). In both genera the anguloarticular is long with a horizontal dorsal surface. The usual cyprinid condition, exemplified by Neobola and Chelaethiops (Figs 8A & C), is for the anguloarticular to be short and deep with a sloped or concave dorsal border. This condition also appears general for teleosts (see Nelson, 1972). In Rastrineobola the jaw articulation is situated so far forward that it lies below the anterior half of the orbit (cf. below, or posterior to the centre in other neobolines). Only in Engraulicypris, amongst bariliines, is the jaw articulation so far forward (see below). A feature also shared by Mesobola and Rastrineobola is the elongation and ventral curvature of the posterior chamber of the swimbladder. Comparative out-group data is too sparse to recognize this feature as a synapomorphy, but a brief survey of cyprinids suggest the condition is, at least, unusual. In summary Neobola and Chelaethiops, and Mesobola and Rastrineobola form paired sister groups related on a synapomorphy scheme involving ethmovomerine, frontal, jaw bone, suspensorial and jaw muscle morphology (Fig. 20). The relationships of the neobolines are with certain bariliines. Relationships of the neoboline group The neobolines share with the bariliine genera Engraulicypris, Leptocypris, Raiamas and Opsaridium the following synapomorphies: 1. A divided adductor mandibulae A, muscle. In Leptocypris and Engraulicypris the fibres of A,/?atf insert partly into the fascia of A u ant and partly into the rictal tissue as in the neobolines. In Raiamas, Opsaridium and South-East Asian Barilius, all the fibres of A { post insert into the fascia of A,anf (Fig. 15), a condition taken to represent the predecessor of the more complex arrangement in the neobolines, Leptocypris and Engraulicypris. A REVIEW OF THE AFRICANi NEOBOLINE CYPRINID FISHES 1 8 1 2. Pectoral and pelvic axial scales. Howes (1983) proposes a fundamental dichotomy of the bariliine group based on axial scale type (viz: elongate 'typical' scales versus modified scales in the form of fleshy lobes). Amongst the neobolines, axillary scales are reduced in some species of Mesobola and are lacking in Rastrineobola. In bariliines, axillary scales are absent in Engraulicypris. From the widespread distribution of axial scales amongst neoboline and bariliine genera, it is assumed that their absence in those above cited taxa are indepen- dent losses. Where scales are reduced or absent, this condition is confined to lacustrine species. 3. Derived ethmovomerine morphology. Amongst the bariliines, only Leptocypris and Engraulicypris have an ethmovomerine architecture approaching that of the bariliines. In neither genus is there a dorsal channelling of the supraethmoid as in neoboline genera, but in Leptocypris there is a slight lateral elevation of the bone (Fig. 3F). In some Leptocypris species and in Engraulicypris there is an omega-shaped ethmoid indentation, anterior elongation and perforation of the vomer (see Howes, 1980; 1983). These are features shared with the neobolines Mesobola and Rastrineobola. This pattern of ethmovomerine mor- phology is disjunct throughout Leptocypris, Engraulicypris and neoboline species and may, therefore, be a case of homoplasy. Likewise, a somewhat channelled supraethmoid occurs in a group of South-East Asian and Indian Barilius species. In these taxa, however, the ethmoid bloc is depressed, rather than laterally compressed as in the neobolines, and other characters such as tubercle pattern and palatine morphology suggest that they form a lineage distinct from that of the neobolines, Leptocypris and Engraulicypris. One other feature to be considered is the absence in Engraulicypris of paired uroneurals. It was noted above (p. 178) that these elements are lacking in all neoboline genera, and their loss might be construed as a synapomorphy. If this is the case, then Engraulicypris would appear to be the sister group to the neobolines, thence to Leptocypris. In the synapomorphy scheme presented here (Fig. 20), the caudal fin character has been reserved until such time as more complete comparative data on its distribution are available. In summary, the neobolines form the sister group to that comprising Leptocypris and Engraulicypris, which in turn is the sister group to Raiamas. This combined assemblage comprises the sister group to the South-East Asian bariliines (possibly including some Indian 'Barilius' and Opsaridium. Neoboline distribution and its biogeographic implications Neoboline taxa have a wide distribution in Africa, embracing the 'ichthyofaunal provinces' Roberts (1975) termed Nilo-Sudanian, East Coast, Guinean, Zambesian and Zairean. Neobola species occur in eastern flowing rivers of Ethiopia and Somalia, northern Kenya and in Lake Turkana (Fig. 21). Chelaethiops, the derived sister group of Neobola, is extensively distributed throughout the Zairean, Guinean and Nilo-Sudanian provinces and also includes Lakes Tanganyika and Rukwa (Fig. 21). Mesobola is present in Lake Albert, the Malagarasi, Rufiji and Zambesi systems, and eastern flowing rivers as far south as Natal (Fig. 22). The genus is also known from the Orange River on the western side of Africa, although there is some doubt about the record from the Cunene River; see p. 170. Rastrineobola occurs only in the Lake Victoria basin-including Lake Kioga (Fig. 22). The most notable feature of neoboline distribution is the geographical division of the genera by the eastern Rift system, so that Chelaethiops is the only genus with a continuous westward extension. When depicted as an area cladogram, the branching sequence of neoboline taxa shows a sister-group relationship between Nilotic and Zairean areas and East-Coast and Zambesian (Fig. 23). The sister group of the neobolines, Leptocypris + Engraulicypris, display a congruent area pattern, with Lake Malawi forming the sister-area to the Nilo-Zairean (Fig. 22). Within Leptocypris, those species considered as derived, weynsii, lujae and modestus, are Zairean, again a pattern in agreement with that of the derived neoboline, i.e. Chelaethiops, species; see below. 1 82 GORDON J. HOWES On the eastern side of the Rift, the area relationship signified by the sister group Mesobola + Rastrineobola, is between East Coast-Zambesian + Lake Victoria basin. The distributional pattern of these sister-group pairs is readily explicable on vicariance events involving, in the case of Neobola and Chelaethiops, the formation of the Rift system, and, in that of Mesobola and Rastrineobola, the isolation of the latter in the Victoria basin. Roberts (1975) includes Lake Victoria in the East-Coast province, and this geographical relationship is certainly borne out by the neoboline phylogeny. Chelaethiops also occurs in both the Malagarasi and Lake Rukwa. This distribution can either be interpreted as a subsequent dispersal from Lake Tanganyika or, as representing the result of an interrupted (vicariant) distribution due to the topographical evolution of that lake; see Banister & Clarke, 1980. The synapomorphy scheme of Chelaethiops species (Fig. 24) makes the latter interpretation more economical. Chelaethiops congicus (Zairean) has least derived features and together with C. rukwaensis (Lake Rukwa and Malagarasi) and C. minutus (Lake Tanganyika) forms the sister group to the derived species C. bibie (Nilo- Sudanian) and C. elongatus (Zaire-Guinean); see Fig. 24 for character summary. Mesobola occurs sympatrically with Chelaethiops in the Malagarasi drainage and the Lualaba, it is also disjunct in distribution, being found in the Orange River below the Aughrabies Falls on the western side of the continent. There is a single, unconfirmed record of its presence in the Cunene (see p. 170). Roberts (1975 : 309) supposed this distribution to be the result of dispersal through South-West Africa. It would be more parsimonious to recognise in this pattern the fragmentation of a formerly uninterrupted distribution. In terms of historical biogeography, the neobolines seem uninformative. This is due partly to the genera resolving only into two-area cladograms, and the mostly unresolved interrelationships of their contained species. Indeed, for Mesobola, a species cladogram cannot be constructed as the species are presently recognised only on the basis of mainly, meristic differences. For Neobola, of the three species, one, N. fluviatilis, is possibly a population variant of another, N. bottegi, and the third, N. stellae is a lacustrine endemic. The other reason is that there are few cladograms of African freshwater fishes which can be used in broader comparison with neobolines. Only three phylogenies can be considered as a basis for constructing area cladograms; those of Vari (1979), Parenti (1981) and Howes (1983). Vari (1979) studied the characoid families Citharinidae and Distichodontidae, recognising them as sister groups. Both families are widespread throughout Nilo-Sudanian, Guinean, Zairean, East-Coast and Zambesian provinces. Within the Distichodontidae, most taxa, which according to Vari's scheme of interrelationships are the derived ones, occur in Zairean and lower Guinean regions. As a simplified area cladogram, the distichodontid pattern is one of repeated dichotomy between Nilotic and Zairean-Guinean regions (Fig. 25). Parenti's (1981) geographical analysis of African aplocheiloid cyprinodonts demonstrates a sister-group relationship between Zairean-Guinean (derived forms) and Nilo-Sudanian, Zambesian-East Coast and Quanzan provinces (Fig. 25). The bariliine relationships presented by Howes (1980; 1983) show both Opsaridium and Raiamas with Asiatic relatives and representatives. Opsaridium has as its sister group the South-east Asian Barilius (and possibly some Indian species, see above, p. 180), and Raiamas is represented also in India and Burma. At this high level of universality, the pattern of bariliine distribution is virtually concordant with that presented by Parenti (1981) for Old World aplocheiloids (cf. fig. 23 in Parenti with fig. 47 in Howes, 1980). Interestingly, all these patterns - aplocheiloids, characoids, bariliines and neobolines -exclude the Cape Province (see below). African ichthyogeography and biotic subdivision Too few data are available to form any refined picture of African ichthyogeographical history. Those that are available suggest a widespread, plesiomorphic fauna disrupted by A REVIEW OF THE AFRICAN NEOBOLINE CYPRINID FISHES 183 a Zairean-Nilotic break with a subsequent (or even contemporaneous) Zairean-Guinean fragmentation. To date, studies of African ichthyogeography have been little more than catalogues of endemism and scenarios of dispersals (see Greenwood, 1983 for discussion). The various hypotheses proposed for African freshwater fish distribution are ad hoc assumptions based on the supposedly known histories of past drainage patterns. An example of this approach is given by Livingstone et al (1982) who account for fish distribution patterns by invoking dispersal from refugia, competition and 'powers of dispersal'. These authors find the ' . . . pattern of faunal similarities surprising . . . ' and rather than accepting that this pattern reflects a previously uniformly distributed fauna (Greenwood, 1983) would prefer to see in it a reflection of '. . . more recent faunal exchange'. The same problems have beset discussions of the biogeography of other African faunas and, as for fishes, ecological parameters are seen as the determinate factors in shaping dis- tributional pattern. Two recent examples are works dealing with molluscs (Brown, 1978) and birds (Crowe & Crowe, 1982). According to Brown ' . . . many distributional patterns seem to be dependent mainly on existing ecological conditions'. He does, however, draw attention to the taxonomic relationships between southern east African and Malagasian molluscs. Crowe & Crowe correlate their avian zones with vegetation types, although admitting that the distributional patterns of passerine and non-passerine birds cannot be explained solely on environmental factors; there is no reference to the possible phylogenetic relationships of the respective bird groups. Similarly, the reasoning behind accounts for mammal distribution has been entirely eco- logical. Indeed, Rautenbach (1978) emphasises that faunal interrelationships should be inter- preted from an ecological point of view. No consideration has been given to a vicariographic approach. There is a cladistic analysis of African bufonids by Grandison (1981) which shows that the plesiomorphic lineage, represented by Capensibufo, is restricted to Cape Province. A reduced area cladogram of the other bufonid taxa also reveals repeated east-west dichoto- mies. Interestingly, Grandison remarks of Capensibufo that it may ' . . . have had an austral origin'. It was noted above that some groups of cyprinids, characoids and cyprinodonts are congru- ent in their distribution in being absentees from the Cape Province. The relationships of those freshwater fishes endemic to the Cape are at present largely unknown. According to McDowall (1973) the South African galaxiid, Galaxias zebratus, may have a close phylo- genetic relationship with Brachygalaxias bullocki in Chile, although McDowall would prefer to recognize any affinity between the two as convergence. Reid (pers. comm.) has pointed out that the Labeo umbratus group of the Cape may be more closely related to Asian than to other African Labeo species. The ichthyofaunal peculiarities of the Cape are paralleled by its flora. Miller (1982) in reviewing bryophyte distribution concludes that the Cape was ' ... an island which was left behind and later caught up with the primary continental block It is clear that if the phylogenetic relationships of the endemic Cape fishes were resolved, a general biogeographic pattern for this region would begin to emerge. This example serves to underline Greenwood's (1983) thesis that only by resolving the phylogenetic relation- ships of African freshwater fishes will any understanding be gained of their present-day distributional patterns. Acknowledgements The manuscript benefited greatly from the criticisms, advice and information offered by Drs P. H. Greenwood, K. E. Banister and G. M. Reid My sincere thanks are due to Bernice Brewster, Margaret Clarke, Debbie Green and Adrian Penrose for assisting with morphometric and other data, to Tony and Jane Hopson for supplying additional 184 GORDON J. HOWES data on Lake Turkana specimens, to Dr Lynne Parent! for informative discussions on biogeography, and to Dr Thys van den Audenaerde, Luc de Vos, Dr Donn Rosen and Dr Richard Vari for the loan of specimens. I owe special thanks to Drs Martien van Oijen and Frans and Els Witte for their warm hospitality and assistance in securing specimens at Mwanza. References Bailey, R. G. & Matthes, H. 1971. A new species of Engraulicypris (Cyprinidae) from Tanzania, East Africa. Revue de Zoologie et de Botanique Africaine 83(1-4): 79-83. Banister, K. E. & Clarke, M, A. 1980. A revision of the large Barbus (Pisces, Cyprinidae) of Lake Malawi with a reconstruction of the history of the southern African Rift Valley lakes. Journal of Natural History 14: 483-542. Bell-Cross, G. 1965a. 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Manuscript accepted for publication 6 December 1983 British Museum (Natural History) Tilapiine fishes of the genera Sarotherodon, Oreochromis and Danakilia Dr Ethelwynn Trewavas The tilapias are cichlid fishes of Africa and the Levant that have become the subjects of fish-farming throughout the warm countries of the world. This book described 41 recognized species in which one or both parents carry the eggs and embryos in the mouth for safety. Substrate-spawning species, of the now restricted genus Tilapia, are not treated here. Three genera of the mouth-brooding species are included though in one of them, Danakilia, the single species is too small to warrant farming. The other two, Sarotherodon, with nine species, and Oreochromis, with thirty-one, are distinguished primarily by their breeding habits and their biogeography, supported by structural features. Each species is described, with its diagnostic features emphasised and illustrated, and to this is added a summary of known ecology and behaviour. Conclusions on relationships involve assessment of parallel and convergent evolution. Dr Trewavas writes with the interests of the fish culturists, as well as those of the taxonomists, very much in mind. 580pp, 188 illustrations include halftones, diagrams, maps and graphs. Extensive bibliography. Publication 1983. 50 0565008781 Publications Sales British Museum (Natural History) Cromwell Road London SW7 5 BD England Titles to be published in Volume 47 Miscellanea A review of the Mastacembeloidei, a suborder of synbranchiform teleost fishes Part II: Phylogenetic analysis. By Robert A. Travers A review of the anatomy, taxonomy, phylogeny and biogeography of the African neoboline cyprinid fishes. By Gordon J. Howes The haplochromine species (Teleostei, Cichlidae) of the Cunene and certain other Angolan rivers. By Peter Humphry Greenwood Miscellanea Anatomy and evolution of the feeding apparatus in the avian orders Coraciiformes and Piciformes. By P. J. K. Burton A revision of the spider genus Cyrba (Araneae: Salticidae) with the descriptions of a new presumptive pheromone dispersing organ. By F. R. Wanless Printed in Great Britain by Henry Ling Ltd., at the Dorset Press, Dorchester, Dorset Bulletin of the British Museum (Natural History The haplochromine species (Teleostei, Cichlidae) of the Cunene and certain other Angolan rivers Peter Humphry Greenwood Zoology series Vol47 No 4 27 September 1984 The Bulletin of the British Museum (Natural History), instituted in 1949, is issued in four scientific series, Botany, Entomology, Geology (incorporating Mineralogy) and Zoology, and an Historical series. Papers in the Bulletin are primarily the results of research carried out on the unique and ever-growing collections of the Museum, both by the scientific staff of the Museum and by specialists from elsewhere who make use of the Museum's resources. Many of the papers are works of reference that will remain indispensable for years to come. Parts are published at irregular intervals as they become ready, each is complete in itself, available separately, and individually priced. Volumes contain about 300 pages and several volumes may appear within a calendar year. Subscriptions may be placed for one or more of the series on either an Annual or Per Volume basis. Prices vary according to the contents of the individual parts. Orders and enquiries should be sent to: Publications Sales, British Museum (Natural History), Cromwell Road, London SW7 5BD, England. World List abbreviation: Bull. Br. Mus. nat. Hist. (Zool.) Trustees of the British Museum (Natural History), 1984 The Zoology Series is edited in the Museum's Department of Zoology Keeper of Zoology : Dr J. G. Sheals Editor of Bulletin : Dr C. R. Curds Assistant Editor : Mr C. G. Ogden ISBN 0565 05007 9 ISSNO 07 - 1498 ^Nopp ,87-239 British Museum (Natural History) Cromwell Road London SW7 5BD Issued 27 September 1984 The haplochromine species (Teleostei, Cichlidae) of the Cunene and certain other Angolan rivers *o\ f "^w /? Peter Humphry Greenwood Department of Zoology, British Museum (Natural History), Cromwell Road, London SW7 5BD . BRIT Contents Introduction 187 Methods and materials 188 The haplochromine species of the Cunene river 189 Thoracochromis Greenwood, 1979 189 Thoracochromis buysi (Penrith), 1970 190 Thoracochromis albolabris (Trewavas & Thys van den Audenaerde), 1969 . 197 Orthochromis Greenwood, 1954 206 Orthochromis machadoi (Poll), 1967 206 Pseudocrenilabrus Fowler, 1934 213 Pseudocrenilabrus philander (Weber), 1897 214 Serranochromis Regan, 1920 216 Serranochromis (Sargochromis) Regan, 1920 216 Serranochromis (Sargochromis) gracilis sp. nov 225 Serranochromis (Serranochromis) Regan, 1920 228 Serranochromis (Serranochromis) thumbergi (Castel.) 228 Serranochromis (Serranochromis} macrocephalus (Blgr) 229 Serranochromis (Serranochromis) angusticeps (Blgr) and S. (S.) robustus jallae(E\gr) 229 Zoogeographical considerations 229 Appendix I 233 The generic status of various Angolan haplochromine species previously referred to Haplochromis by Regan (1922), Trewavas (1973) and Bell-Cross (1975). Appendix II The generic status of Pelmatochromis welwitschi Blgr, 1898 234 Acknowledgements 238 References 238 Introduction L 'Angola est un plateau d' ou descendant de nombreux Jleuves et rivieres qui cachet encore bien des secrets Poll (1967:16) Despite Poll's (1967) extensive monograph on the fishes of Angola, and the work of Trewavas (1964, 1973) and Bell-Cross (1975) much has still to be learnt about the biology, taxonomy and zoogeography of the haplochromine cichlid species in this region of Africa (see Greenwood, 1979). A basic inventory of the species has been worked out, but many taxa are known only from the type specimen, by a limited number of type specimens or by some specimens whose locality is recorded no more precisely than 'Angola'. Above all, almost nothing is known about the phyletic relationships of the species, and hence zoogeographical conclusions based on them are correspondingly uncertain. Judging from the present-day hydrography of Angola, especially the isolated rivers which discharge directly into the Atlantic, and the numerous tributaries emptying into the Zaire system, one might expect a high degree of localized endemicity in the various rivers. In other Bull. Br. Mus. nat. Hist. (Zool.) 47(4): 1 87-239 Issued 27 September 1984 187 188 P. H. GREENWOOD words, the physical background would seem ideal for promoting vicariant speciation, a situation that is, indeed, suggested by some of the taxonomic data already available. Thus it was with considerable pleasure and interest that I accepted an invitation from Dr M. Penrith (then of the Windhoek Museum) to study a large collection of cichlid fishes from, principally, the Cunene river. The Cunene is one of the least studied Angolan rivers, and physiographically is one of the most isolated in the country. The collection has provided an opportunity to redescribe a number of species on the basis of many more specimens than were previously available, and to confirm the presence in the Cunene of species either not previously recorded from there or recorded with some uncertainty. Also, it has established that several species have an extensive distribution within the river itself, their ranges stretch- ing from or near the river mouth, almost to its northernmost tributaries. Less has been learnt about the relationships of the endemic Cunene species, and the collec- tion has underlined the still unsatisfactory taxonomic situation surrounding species of the Serranochromis subgenus Sargochromis. However, a species currently of indeterminable status 'Haplochromis' welwitschii (Blgr), whose type specimen is probably from the Cunene, can now be referred to the genus Chetia, a taxon otherwise known from the Limpopo system in South Africa (see Appendix II), and a tributary of the Zaire system (see Balon & Stewart, 1983). In terms of species numbers and morphological diversity, the Cunene seems to have a haplochromine fauna more complex than that in any other Angolan river and, indeed, more diverse than that of the Zambezi-Kafue systems. The new collection also apparently corroborates existing ideas that the Cunene fauna, on a broad zoogeographical scale, has phyletic affinities with both the Zaire and the Zambezi drainage systems (Trewavas, 1964, 1973; Bell-Cross, 1975; Roberts, 1975). However, sister-group relationships for the endemic haplochromines both within and outside the different sytems still cannot be established. Zoo- geographical problems are compounded by the fact that precise specific identification is impossible for most Cunene representatives of the Serranochromis (Sargochromis) species complex, and is unlikely to be obtained until more specimens, coupled with data on male breeding colours, are available from the different river systems within and outside Angola. Methods and materials Methods. Measurements and counts generally are those used in my other papers on haplo- chromine fishes (see Greenwood, 1981). Measurements relating to the neurocranium are those used in Greenwood (1980: 4-6); an additional measurement used here, ethmovomerine length, is taken directly from the anterior tip of the vomer to the most ventrolateral point on the lateral ethmoid bone. When the length of the ascending premaxillary process is given for whole specimens it is measured directly from the dentigerous surface of the bone, between the teeth on either side of the midline, to the distal tip of the processes (determined through the skin by moving the premaxillae gently forwards and downwards). When this length is taken from a skeletal preparation, the depth of the dentigerous arm is excluded, and the reference points are those illustrated in Greenwood (1980: 5, fig. 2), viz from the distal tip of the processes to a hori- zontal line drawn level with the upper margin of the dentigerous arm immediately posterior to the basal region of the ascending processes. Measurements of the lower pharyngeal bone are those employed by Bell-Cross (1975: 410), viz: length is taken along the median axis of the bone, from the anterior tip of its shaft to a line drawn transversely between the tips of the posterior horns. Lower pharyngeal breadth is measured directly between the outer edges of the two horns. A feature not previously mentioned in the description of haplochromine species is the anal sheath scales. My attention was drawn to these scales when examining part of the type series of Tilapia steindachneri Blgr (see p. 190). In these specimens, a distinct but shallow sheath of small, almond-shaped scales, aligned in a single row, lies between the anal fin base and the ventral row of body scales. The long axes of the scales are arranged horizontally, and the scales are either imbricate or spaced, sometimes widely spaced. CUNENE RIVER HAPLOCHROMINE SPECIES 189 It seems that anal sheath scales occur in a number of haplochromine lineages. A sheath, or at least some characteristically almond-shaped scales, has been found in species from Lakes Victoria, Tanganyika and Malawi, as well as in some fluviatile taxa. Sheath length varies intraspecifically to a considerable extent. It can be present along almost the entire base of the fin, or it may be confined to the base of the spinous part (apparently the common- est condition). Often it is represented merely by a few isolated scales. Since the scales are easily dislodged, the latter condition may be artefactual. The taxonomic value of the anal sheath, in whatever form it is present, cannot yet be assessed. Materials. All the type specimens of Angolan haplochromine species in the BM(NH) collec- tions were examined, as were other specimens identified as conspecific with these types or with type specimens of Angolan species held in other institutions. Likewise, all the BM(NH) material of Serranochromis and Pseudocrenilabrus species was studied, together with the type and other specimens of 'Haplochromis'' darlingi, a species first recorded from Angola by Poll (1967). In addition, the following material was borrowed from the Zoological Museum of Hamburg (ZMH) and the Musee Royal de 1'Afrique Centrale, Tervuren (MRAC). ZMH 4599 Haplochromis species (7 specimens) Cunene R. 4599a Haplochromis species (1 specimen), Cunene R. at Capelongo. 1300 Serranochromis angusticeps (1 specimen), Cunene R. at Capelongo. 1307 Serranochromis angusticeps (1 specimen), Cunene R. at Capelongo. 1718 Serranochromis robustus jallae Cunene R. at Miilongo Fiirt. 1719 Serranochromis thumbergi (2 specimens) Cunene R. at Capelongo. The identity of all these Serranochromis specimens has been confirmed. 1 722 Haplochromis frederici (4 specimens), Cunene R. at Capelongo. Two specimens are members of the Serranochromis (Sargochromis) giardi-codringtoni complex (see pp. 2 1 7-224 below), and two probably can be referred to S. (Sargo.) coulteri (Bell-Cross). Musee Royal de 1'Afrique Centrale (MRAC), Tervuren. MRAC 154779-780 Haplochromis welwitschii, Sanguenque Uembe Cuanaa, Angola. MRAC 66470 Haplochromis schwetzi, holotype, Cuango R., Angola. MRAC 163992; 164013-016; 164023-026; 164027-032; 164033-39 Haplochromis schwetzi, paratypes (26 specimens), Cuango R., Angola. MRAC 163981-986 Haplochromis darlingi, Lac Calundo, Angola. Other material examined is listed in the text. Regrettably, as a result of extensive reorgani- zation now been carried out in the fish collections of the Vienna Museum, it was impossible to examine the types of two Steindachner (1866) species: Chromis humilis and Chromis acuticeps. Both taxa are described, simply, as coming from Angola. Fortunately the types of both species were carefully examined by my colleagues Dr Ethelwynn Trewavas, and later by Mr G. Bell-Cross (now of the Port Elizabeth Museum, South Africa). I have been able to use the notes and recollections of both these people, to whom I am most indebted. The haplochromine species of the Cunene river THORACOCHROMIS Greenwood, 1979 Several Angolan species, currently referred to the genus Haplochromis, show the diagnostic features of Thoracochromis, viz an abrupt size change between the small scales on the chest and the larger scales on the ventrolateral aspects of the flanks, a marked anteroventral embayment of the cheek squamation (with, in some species, a narrow, horizontal naked area lying between the cheek scales and the preoperculum), and the absence of true ocelli, but not discrete spots, on the anal fin or adult males (see Greenwood, 1979: 290-292). 190 P. H. GREENWOOD The Angolan species now placed in Thoracochromis are: Haplochromis lucullae (Blgr), 1913; H. albolabris Trewavas & Thys van den Audenaerde, 1969; H. schwetzi Poll, 1967, and H. buysi M.-L. Penrith, 1970. Haplochromis lucullae was treated as a junior synonym of H. acuticeps (Steindachner, 1866) by Regan (1922: 255), but the species has been informally 'resurrected' by several recent authors, notably Trewavas (1964: 8-9, 1973: 31), Penrith (1970: 170-171) and Bell- Cross (1975: 427). Unfortunately, I have not been able to examine the holotype of H. acuticeps (see p. 1 89) but from Dr Trewavas' comments, based on detailed examination of that specimen, its separation from lucullae, at least at the species level, is justified (see also Trewavas, 1973: 31). Regrettably, neither Steindachner's (1866) original description, nor Trewavas' later reexamination of the acuticeps type specimen provide any information on the nature of the size-change at the chest-abdominal scale transition line, nor are there data on the nature of the cheek squamation. Thus it is impossible to comment on the generic assignment of ''acuticeps'. Steindachner's figure, however, suggests that the scale transition is of the Thoracochromis type. With one exception (Th. schwetzi), and unlike species of Thoracochromis from the Nile, Lake Turkana and the Zaire river system, none of the Angolan species has more than 4 or 5 upper lateral line scales each separated from the dorsal fin base by one large and one small scale. This low number is thought to represent the primitive condition, the higher number (8 or 9 scales) occurring in the other species being the derived one (Greenwood, 1979: 291). As compared with the Nilo-Zairean taxa most Angolan species have more scales in the lateral-line series and higher modal counts for this feature. Again, an exception is Th. schwetzi, whose lateral line counts are like those in the Nilo-Zairean species; interest- ingly, Th. schwetzi occurs only in the Cuango river, an Angolan affluent of the Zaire system. In all other meristic and morphometric features the Angolan Thoracochromis do not lie outside the range of variability found in other members of the genus. The significance, if any, of the differences in squamation cannot be assessed until more data are available from those Angolan species which are currently represented only by one or a few type specimens. Species previously referred to Haplochromis and which are not members of Thoraco- chromis, are discussed in Appendix I. Thoracochromis buysi (Penrith), 1970 SYNONYMY Haplochromis buysi Penrith, M.-L., 1970. Cimbebasia, ser A, 1 (7): 168-171, plate 2; fig. 1. Holotype: SM5099, a specimen 75mm standard length, from the Cunene river mouth. Paratype: SAM 25243, a specimen 6 1 mm SL from the same locality. This specimen is now damaged extensively, and was not used in the redescription of the species. It is, however, conspecific with the holotype. Tilapia steindachneri (part) Boulenger, 1913. Ann. Mag. nat. Hist. (8) 12: 483. Five of the syntypical specimens only (BMNH 1907.6.29:141-5, from the Que river). The largest specimen, 104.5 mm SL, alone is in reasonable condition. Although Boulenger (1913) did not select a holotype, he did later (1915) designate one specimen as 'Type' in the caption to a figure of that specimen. The fish in question is one of the syntypes from Mossamedes which Regan (1922) included in the species Sargochromis mellandi. Thus the inclusion of the five Que fishes in the synonymy of Thoracochromis buysi (Penrith), 1970 raises no question of nomenclatural priority for Boulenger's earlier name ' steindachneri'. Haplochromis acuticeps (part): Regan, 1922. Ann. Mag. nat. Hist. (9) 10: 255 (the syntypical specimens of T. steindachneri noted above; BMNH 1907.6.29:141-5). DESCRIPTION. Based on 46 specimens, including the holotype, 44-0-1 18-0 mm standard length. Depth of body 29-4-34-7 (M = 32-0)% of standard length, length of head 30-4-36-4 (M = 31-5)%. Dorsal head profile gently curved (almost straight in a few specimens), sloping at an angle of 35-40 to the horizontal, the angle increasing with the fish's srze. The upper margin of CUNENE RIVER HAPLOCHROMINE SPECIES 191 Fig. 1 Thoracochromis buysi. Adult male (1984.2.6: 24). Drawn by G. J. Howes. Scale = 20 mm. the eye is coincident with, or lies immediately below the dorsal profile of the head, but never extends above it. The extent to which the curve of the profile is interrupted by the intrusion of the premaxillary ascending process varies, but is never marked and may be influenced by preservation methods. Preorbital depth 18-5-26-0 (M = 22-9)/o of head length, showing slight positive allometry with standard length; least interorbital width 16-6-23-6 (M=19-4)% of head. Preorbital depth is generally greater than least interorbital width, but in some individuals the measure- ments are equal; in no specimen examined is the interorbital width greater than the preorbital depth (cf. Th. schwetzi where the interorbital is wider than the preorbital is deep). Snout length shows clear cut allometry with standard length. The range for the whole sample is 31-0-39-0% of head; in specimens less than 70mm SL (n=17) it is 31-0-35-3 (M = 33-l)% and in larger individuals (71-0-1 18-0 mm SL, n = 29) it is 34-5-39-0 (M = 36-7%). The snout is from 1-0-1-3 times longer than broad (modal range 1-0-1-1). Eye diameter is negatively allometric with standard length; for the whole sample it is 25-4-36-2% of head length, in fishes <70 mm SL it is 28-6-36-2 (M = 33-6)%, and in larger individuals 25-4-33-3 (M = 28-3)%. Cheek depth is 18-2-27-8 (M = 22-7)% head, and shows no obvious allometry with standard length. Caudal peduncle length is 16-2-22-0 (M= 19-0)% of standard length, and 1-3-1-9 (modal range 1-5-1-7) times its depth. Mouth horizontal or almost so, the lips slightly but noticeably thickened, the jaws equal anteriorly. The posterior tip of the maxilla reaches a vertical closer to the anterior orbital margin than to the nostril, rarely extending to a vertical through the margin of the orbit. Lower jaw 1-5-2-0 (mode 1-8) times longer than broad, its length 33-3-39-0 (M = 36-0)% of head length. Ascending processes of the premaxilla 25-7-34-3 (M = 30-6)% of head. Gill-rakers and pharynx. There are 8-10 (mode 10), relatively short and moderately stout gill-rakers in the outer row on the lower part of the first arch; the lowermost one or two rakers are smaller than the others. The rakers are transversely elongate, with the upper surface produced into two or three cusp-like projections. Microbranchiospines are present. In his original description of Tilapia steindachneri (see synonymy above), Boulenger (1913) gave the gill-raker count as 13-14, a count repeated in his redescription of 1915. These figures, however, apply only to those syntypes which Regan (1922) ultimately referred to Sargochromis mellandi. The remaining syntypes, which I refer to Th. buysi, have only 9 or 10 rakers. 192 P. H. GREENWOOD The dorsal pharyngeal epithelium is thickened and thrown into well-defined, approxi- mately longitudinal furrows, the crests of the ridges often further developed into low papillae. Immediately anterior to the toothed upper pharyngeal bones of each side, the buccal roof is produced into a prominent pad which, however, has neither the size nor the shape of the visor-like hanging pad found in certain cichlid genera (see Trewavas, 1974: 389-392, and Greenwood, 1983: 265-267). Scales are ctenoid below the level of the lower lateral-line, cycloid above it and on the chest. The chest scales are small, except for a midventral row of slightly larger scales, and are noticeably smaller than those on the ventrolateral aspects of the flanks and on the belly. The size transition is abrupt and takes place along a line connecting the pectoral and pelvic fin insertions, or a little behind that line. There are 32 (rare) to 36 (rare) scales, modally 34, in the lateral-line series, 4^-6^ (modally 5 or 5) between the dorsal fin origin and the upper lateral-line, and 7-9 (mode 8) between the pectoral and pelvic fin bases. Cheek with 3-5 (mode 4) scale rows, the scaled area with a clearly demarcated, naked embayment anteroventrally. Each of the last 3 or 4 pored scales in the upper lateral-line is separated from the dorsal fin base by one large and one small Fins. Dorsal with 14 (fl), 15 (f!7), 16 (f26) or 17 (f2) spinous and 10 (f2), 11 (f24), 12 (f!8) or 13 (2) branched rays. Anal with 3 spinous and 7 (f8), 8 (f37) or 9 (fl) branched rays. In all but three of the 46 specimens examined, small, almond-shaped sheath scales are present at the base of the anal fin (see p. 188 above). The horizontal extent of these varies from a row extending along the entire spinous part of the fin and reaching the 3rd-5th branched ray, to a few isolated and often non-imbricating scales at the base of either or both the spinous and the anterior part of the soft fin; sometimes only one or two scales are present and then usually at the base of the first one or two spines. The pectoral fin length is 19-6-26-4 (M = 2H)% of standard length, 61-3-80-0 (M = 70-2)% of head length. The pelvic fins have the first branched ray longer than the second, most noticeably so in adult males, but never produced into a filamentous extension, and never reaching to the origin of the anal fin. The caudal fin generally is subtruncate, but is almost truncate in a few specimens; it is scaled on its proximal third to half. Teeth. The outer row in both jaws of fishes up to ca 90 mm SL is composed, mostly, of relatively slender, unequally bicuspid and gently recurved teeth. The small minor cusp is angled away from the vertical axis of the major cusp (Fig. 2 A). In teeth from the upper jaw, the tip of the major cusp usually lies within, or but slightly beyond, the vertical formed by the outer margin of the tooth; in lower jaw teeth, however, the tip often lies well outside that line, as it may occasionally do in upper jaw teeth as well. Posteriorly in the premaxillary outer row of most specimens there are from 2 to 8 unicuspid teeth. These teeth, unlike those in Astatotilapia (see Greenwood, 1979), are not noticeably enlarged nor are they caniniform. Although some unicuspids are present laterally and anteriorly in the jaws of fishes less than 90 mm SL (especially those in the 75-90 mm range), their frequency only increases in specimens over 90 mm SL, becoming the predominant form in fishes more than 1 10 mm SL; even in these specimens, however, a few weakly bicuspid teeth are present in both jaws. The unicuspids are slender and slightly recurved, and do not have the near-cylindrical neck and crown of typical caniniform teeth. Both uni- and bicuspid teeth often show pronounced wear at the tip of the crown. There are 42-66 (modal range 50-62) teeth in the outer premaxillary series, the number not showing any clear-cut allometry with the fish's standard length. Inner series. It is difficult to generalize about tooth form in these rows because there is both a change with growth and, apparently, some inter-population differences as well. Most fishes less than 85 mm SL have a predominance of slender tricuspid teeth in the inner rows; the median cusp of these teeth is longer and broader-based than are the cusps flanking CUNENE RIVER HAPLOCHROMINE SPECIES 193 0-5 Fig. 2 Outer row jaw teeth of: A, Thoracochromis buysi; B, Th. albolabris; C, Orthochromis machadoi. A & B are anterior premaxillary teeth, C, a tooth from the anterior part of the dentary. it. A few slender bicuspid and weakly bicuspid, nearly unicuspid teeth are interspersed amongst the tricuspids, especially in fishes over 70 mm SL. Such teeth become more frequent in specimens between 75 and 85 mm SL. In specimens from certain localities, however, this admixture of tricuspids, weakly tricuspids and bicuspids is found in much smaller fishes, even among individuals as small as 47 mm SL. Fishes above ca 80 mm SL from all localities show a further increase in the number of bi- and unicuspid inner teeth, coupled with a decline in the number of tricuspids. These latter also tend to be less distinctly tricuspid, the median cusp gaining in dominance over the lateral ones. Specimens more than 90 mm SL have an essentially unicuspid inner dentition, although a few bicuspid and weakly bicuspid teeth persist; only the largest fish examined, 118-0 mm SL, has the inner rows composed solely of unicuspids. Anteriorly and anterolaterally the inner teeth are arranged in 2 (mode) or 3 rows, rarely in a single irregular row. Posteriorly in both jaws, however, only a single row of teeth is present. All but a few of the specimens examined have the dental mucosa greatly thickened with the result that just the tips of the teeth are visible. That this situation is a preservation artefact, cannot be overruled. Lower pharyngeal bone and dentition. The lower pharyngeal bone has an approximately triangular and equilateral dentigerous surface; the anterior shaft is short (Fig. 7A). Except for about the posterior four or five teeth in the median tooth rows, the pharyngeal teeth are slender, compressed and cuspidate, and are closely spaced. The exceptional teeth are dis- tinctly coarser and larger than their lateral congeners, but still retain a cuspidate crown. Sometimes a few posterior teeth in the rows immediately lateral to the median row are slightly coarser than the other lateral teeth. The pharyngeal bone itself is not enlarged, and has slender posterior horns. Osteology. Neurocranium. Overall skull morphology in this species (Fig. 10A) departs slightly from the generalized haplochromine type (Greenwood, 1979: 274) in being more slender, with a shallower and narrower otico-occipital region, narrower interorbital and ethmoid regions, and in having a lower and less expansive supraoccipital crest. Also the dorsal skull profile, from the anterior tip of the supraoccipital bone to the tip of the vomer, slopes less steeply (ca 30 compared with ca 45 in the case of Astatotilapia nubila or A. bloyeti; c/Fig. 10A with fig. 6 in Greenwood, 1979). Expressed as percentages of neurocranial length, the orbital depth is 34-8-36-3%, pre- orbital depth 17-4-20-8%, preotic skull length 63-6-66-6%, ethmoverine length 27-0-27-4%, 194 P. H. GREENWOOD depth of otic region 37-5-40-0%, width of otic region 50-0%, and greatest height of supra- occipital crest 16-5-18-2% (Data from three skulls, 22-0, 23-0 and 24-0 mm neurocranial length; for definition of measurements see Greenwood, 1980: 4-5). The apophysis for the upper pharyngeal bones is of the Haplochromis type (Greenwood, 1978); in two of the three skulls examined the basioccipital contribution to the facet is large, but in the third it is greatly reduced. Suspertsorium (Fig. 3 A). There is a distinct gap between the palatine and entopterygoid bones, an unusual features so far recorded only in members of the Ophthalmotilapia assemblage of Lake Tanganyika, and in at least some Lethrinops species (Lake Malawi); for a discussion of this feature see Greenwood (1983: 254-6, and 279). The hyomandibula in Th. buysi (Fig. 3C) has a fairly well-developed anterior flange, but one which is less expansive than that in Orthochromis machadoi (see Fig. 3E). Jaws. The dentary (Fig. 11 A) is a slender bone, with its alveolar surface flared out- wards so as to form a shelf-like overhang above the bone's lateral face. There is no mental projection in the symphysial region, which is, however, a little swollen. The premaxilla (Fig. 8A) has no outstanding features. Its ascending processes are long (almost one fifth longer than the dentigerous arm) and have a slight but obvious posterior Fig. 3 A, Suspensorium of Thoracochromis buysi; B, that of Th. albolabris, both in left lateral view. C, D & E, hyomandibula, in left lateral view, of C, Th. buysi; D, Th. albolabris; E, Orthochromis machadoi. Scale in mm. CUNENE RIVER HAPLOCHROMINE SPECIES 195 inclination at an angle of about 10 from the vertical. The dentigerous arms are laterally compressed and are not expanded anteriorly and anteroventrally to form a beak-like process. Caudal fin skeleton. All the hypurals are free in 22 of the specimens radiographed but in some hypurals 3 and 4 are very closely apposed to one another, and in two others hypurals 1 and 2 are fused. In another fish, hypurals 1 and 2 seemingly are fused distally but are free proximally, as are hypurals 3 and 4. All these observations were made from radiographs thus rendering it difficult to distinguish with certainty between actual fusion and close apposition. Vertebrae. Excluding the fused PU, + U, centra, there are 30 (f8), 31 (flO), 32 (f4) or 33 (fl) vertebrae, comprising 13 (f2) or 14 (f21) abdominal and 16 (f7), 17 (flO), 18 (f5) or 19 (f 1) caudal elements. The syntypical specimens of Tilapia steindachneri, from the Que river, are excluded from these counts; here the range is 28 (fl), 29 (fl) and 31 (f3), comprising 12 (fl), 13 (fl) or 14 (f3) abdominal, and 1 5 (f 1 ) or 1 7 (f4) caudal centra. In her original description of Th. buysi, Penrith (1970: 169) gives the vertebral count (including PL^ + Uj) for the holotype as 16+18; I have checked this figure on a radiograph made in the BM(NH), and find that my count, including the PU, + U, elements, is 14+ 18. Coloration. No information is available on live colours. For material fixed in formol and preserved in alcohol, the coloration is: Females and immature males, with a light brown (beige) ground colour which often becomes silvery on the belly and the flanks below the midlateral line. The intensity and presence of the silvery pigment may depend on factors of preservation since in some specimens it is absent, the beige colour merely lightening on the lower half of the belly. In those specimens which are silvery, faint traces of silver are present on the cheek and, more intensely, on the operculum. Traces of from 8-12 vertical bars are visible on the flanks and caudal peduncle; some of these bars extend almost to the ventral body profile, but most fade and disappear slightly below the level of the midlateral line. The intensity and clarity of the bars is very variable in the sample as a whole, but are reasonably constant within any one sample. Dr Michael Penrith (in litt) has observed, for the small cichlids of the Cunene, that coloration is generally darkest in fishes from the upper reaches of the river. All fins are greyish-hyaline, the dorsal with darker pigmentation between the spines, and dark maculae between the branched rays; the lappets are darker than the areas between the spines. The caudal fin is faintly maculate, with a dark posterior margin; this marginal band is most obvious when the fin is closed. The anal has dark lappets, and some indication of a dark margin to the anterior region of the soft part as well. In some males there are 5 or 6 dark spots, arranged, somewhat irregularly, in two rows on the soft part of the fin; the distal row lies a little above the fin's margin, the proximal row (usually with fewer spots) lies along the middle of the fin. There is no indication of a clear surround encompassing each of the spots, which thus cannot be considered true ocelli. The pelvic fins sometimes have a peppering of dark chromatophores which are most obvious in males. Sexually active males. In the few sexually active males examined, the overall coloration is much darker than that in females and inactive males. Scales above the midlateral line are outlined in dark brown, the vertical barring is moderately intense, the dorsum of the head and the entire snout is dark, almost dusky, as are the rami of the lower jaw and the anterior two-thirds of the lower lip. The branchiostegal membrane and the chest are dusky, but are lighter than the dentaries. The cheek is brown and only a little darker than the ground colour of the body. The membrane between the dorsal fin spines is almost black, but the lappets are hyaline; the soft part of the fin is densely maculate, the spots having a clear centre and a narrow, very dark brown surround. The proximal two-thirds of the caudal fin is covered in similar maculae, but its distal third is a somewhat dusky hyaline; the posterior margin is dark. The anal fin has a dusky hyaline ground colour showing between the large number, 8-10, of pale spots, each with a narrow, dark surround. The spots are arranged in three irregular rows (with from one to three spots in each) on the soft part of the fin. The anal spots are about 196 P. H. GREENWOOD four times larger than the biggest maculae occurring posteriorly on the dorsal fin. The p