M. J. PENRITH A NEW SPECIES OF FLAT FISH, MANCOPSETTA MILFORDI, FROM SOUTH AFRICA, WITH NOTES ON THE GENUS MANCOPSETTA September 1965 September Volume 48 Band Bart 7.077) Deel ANNALS OF THE SOUTH AFRICAN MUSEUM ANNALE VAN DIE SUID-AFRIKAANSE MUSEUM Cape Town Kaapstad The ANNALS OF THE SOUTH AFRICAN MUSEUM are issued in parts at irregular intervals as material becomes available Obtainable from the South African Museum, P.O. Box 61, Cape Town (Cash with order, post free) Die ANNALE VAN DIE SUID-AFRIKAANSE MUSEUM word uitgegee in dele op ongereelde tye na beskikbaarheid van stof Verkrygbaar van die Suid-Afrikaanse Museum, Posbus 61, Kaapstad (Kontant met bestelling, posvry) OUT OF PRINT/UIT DRUK I, 2(1, 3, 5» EO RUD Gy Wo) WE Gy Fob 61, tpi), 70, 3), 8 9(1-3), _ 10(1-3), Ti (0-25) Joints Dle)si 20242) eg (1 3) aaa). Price of this part/ Prys van hierdie deel 25¢ Printed in South Africa by In Suid-Afrika gedruk deur The Rustica Press Pty., Ltd., Die Rustica-pers Edms., Bpk., Court Road, Wynberg, Cape Courtweg, Wynberg, Kaap A NEW SPECIES OF FLATFISH, MANCOPSETTA MILFORDI, FROM SOUTH AFRICA, WITH NOTES ON THE GENUS MANCOPSETTA By M. J. PenriTH* South African Museum, Cape Town (With 2 figures in the text and 1 plate) CONTENTS PAGE Introduction. : : : 181 Mancopsetta milfordi sp. n. . Lo Generic grouping 5 : Ht83 Genus Mancopsetta. ; . 186 Distribution : : F F 187 Acknowledgements. : SOS Summary : : , ; 188 References , : 5 Ba aiksks} INTRODUCTION The genus Mancopsetta was proposed by Gill (1881) to replace the pre- occupied generic name Lepidopsetta used by Gunther (1880) when describing M. maculata, the first of the bothid fishes found which lacked pectoral fins. This species has until now remained the only species in the genus and has been known from a very few specimens found in the Southern Hemisphere. The related genus Achiropsetta (Norman, 1930) was known from two species, both rare and recorded only from the Southern Hemisphere. Recently the South African Museum was presented with two specimens of a bothid fish lacking pectoral fins. These have been assigned to the genus Mancopsetta. Mancopsetta milfordi sp. n. (fig. 1, pl. ITT) Material : S.A.M. 24041: trawled by a commercial trawler in 300 fathoms west of Cape Town. Standard length 393 mm. (Holotype). S.A.M. 23767: trawled by a commercial trawler in 370 fathoms west of Cape Town. Standard length 298 mm. The body is compressed, sinistral and fairly elongate, the maximum depth being about 2% in body length (excluding the caudal fin). The axial portion of the body is thickened relative to the rest of the body in the smaller specimen, * Seconded from the Council for Scientific and Industrial Research Oceanographic Unit, University of Cape Town. 181 5 Ann. S. Afr. Mus. 48 (7), 1964, 181-188, 2 figs., 1 pl. 182 ANNALS OF THE SOUTH AFRICAN MUSEUM but this seems to become less marked with increase in size as it is not noticeable in the larger specimen. The caudal peduncle is very short, being only 4 of the longitudinal diameter of the eye. There is a single straight lateral line on both sides with about 160 scales on the ocular side. The scales are ctenoid with normally eight to twelve spinules. Towards the edges of the fish, especially on or near the fins, the spinules project at an angle away from the body, but on the main trunk they lie flat. The entire head, including the jaws and part of the eyes, is covered with fine scales. The eyes are separated by a low, scaled, bony ridge. All fin rays, including the caudal, have a row of scales. The head from the tip of the maxilla to the hindermost edge of the oper- culum is contained 4 times in standard length, while the greatest diameters of the eyes (both eyes equal) are } the length of the head. The snout is slightly shorter than the eye diameter. There is a small fleshy growth over the front of the maxilla. The mouth reaches back to a point almost level with the posterior edge of the lower eye. Teeth are present on both sides of the jaw but are slightly better developed on the ocular side. The mouth has a very wide gape and is protrusible. The membranes on the ocular side are more protrusible than those on the blind side. There are nine small gill-rakers on the lower arch of the first gill. There is no trace of any pectoral fin on either side. The pelvic fin on the ocular side is larger than that on the blind side. On the eyed side the anterior base of the pelvic fin is median, while posteriorly the base is twisted to the left, i.e. on to the ocular surface of the body (fig. 1). The body proportions and meristic counts of the two specimens are given in Table I and compared with a specimen of M. maculata from the collection of the British Museum (Natural History) (Registered No. 1930.5.6: 41). The colour, preserved in formalin, is brown-grey with the anal and dorsal fins grey slate/blue. There is no trace of any pattern. TABLE I M. milfordi M. milfordi M. maculata Total length .. ae ets a 456 334 239 Standard length ve ae 6 392 298 199 Greatest depth .. ta sa ys 143 (364) 99 (332) 88 (442) Head length .. ae ss st IOI (258) 76 (255) 53 (266) Length of snout she : i 22 (56) 15 (50) 10 (50) Diameter of eye (horizontally ar 24 (61) 20 (67) 17 (85) Interorbital width aie Rie Sc 8 (17) 5 (15) 3 (15) Length of Maxillary .. A 48 (122) 33 (111) 18 (go) Number of scales in lateral line =f 164 177 119 Dorsal rays Ne a > 9 130 133 119 Anal rays 3 56 ate 109 110 98 Pelvic rays, blind side .. Be “8 6 6 5 Pelvic rays, ocular side re Sc 7 7 7 Gill-rakers, lower arch ae 56 9 9 12 Body proportions and meristic counts of M. milfordi and M. maculata. Body proportions in millimetres and in thousandths of standard length in parentheses. A NEW SPECIES OF FLATFISH, MANCOPSETTA MILFORDI 183 Ficure 1. Head of M. milfordi showing the twisting of the posterior portion of the left pelvic fin onto the ocular surface. Mancopsetta milfordi differs from M. maculata in the number of dorsal and anal rays and lateral line scales, the twisting of the posterior end of the left pelvic fin onto the ocular surface and in certain body proportions. It resembles M. maculata, however, in general body shape, especially head shape, and in the type of scales. The species is named for Mr. C. S. Milford, managing director of the trawling firm, Messrs. Irvin and Johnson (Pty.) Ltd., in recognition of generous support for marine biological research. GENERIC GROUPING According to Norman (1934) there are only two genera of bothids (both known only from the Southern Hemisphere) which lack both pectoral fins. 184 ANNALS OF THE SOUTH AFRICAN MUSEUM These two genera, Mancopsetia and Achiropsetta are said to differ in the following characters... . (a) Achiropsetta is said to have a flat scaled interorbital space, whereas that of Mancopsetta is stated to be a naked narrow bony ridge. (b) Achiropsetta is said to be more elongate and to have a thickened trunk. (c) In Mancopsetta the pelvic fin on the ocular side is not directed to the left posteriorly as is said to be the case in Achiropsetta. (dq) In both genera the scales are small and ctenoid, but in Mancopsetta the 8-14 spinules lie flat, whereas in Achiropsetta there are only one or two spinules which are directed away from the body. These differences would seem to be clear cut, but the finding of a second species of Achiropsetia, A. slavae (Andriashev, 1960) and the present species have suggested that the differences between the genera are not so marked as was formerly thought. Neither A. slavae nor M. milfordi fits completely the generic description of the genus in which it has been placed. The distribution of various taxonomic characters among the four species of bothids which lack pectoral fins is shown in Table IT below. TABLE II Achiropsetta Mancopsetia tricholepis slavae maculata milfordi Dorsal rays un A ane ute 132 114-117 116-119 130-133 Anal rays 56 as =i Sic 114 93-96 97-98 109-110 Lateral line scales ae a ? 115 T14-120 164-177 Depth in standard length be ae 2°4. 2 2:2 DOG) Gill-rakers in lower arch a ae g-10 12 12 9 Head in standard length fe He 4°5 3°5 3°38 4 Coloration a = a ae plain patterned patterned plain Fleshy lip on maxilla tip ie J Eypresent present present present Spinules on scales aie sy . vertical vertical flat flat Pelvic fin of eyed side twisted to the left yes no no yes Maximum known total length (mm.) 105 63 270 456 Smallest known total length (mm.) .. 100 48 134 334. Comparison of the four known species of bothid fishes which lack pectoral fins. From the table it is clear that the only important character that the two species of Achiropsetta have in common, and distinct from the two species placed in the genus Mancopsetta, is the unusual form of the scales with vertically projecting spinules. Although A. tricholepis is stated to have a flat scaled interorbital space (Norman, 1930, 1934), a specimen examined from the collection in the British Museum (1933.5.8: 1) shows a clear bony ridge. M. maculata on the other hand was said (Norman, 1934) to have a bony ridge without scales. In the specimen of M. maculata examined however, scale pockets were clearly present on the ridge. It seems likely that the scales were rubbed off in the trawl net. A scaled ridge is therefore present in M. maculata, M. milfordi and A. tricholepis. Nothing is known concerning this feature in A. slavae. A NEW SPECIES OF FLATFISH, MANCOPSETTA MILFORDI 185 Another difference, the thickened trunk in Achiropsetta, is most probably a function of size as it is present in Achiropsetta (of which only small specimens are known) and the smaller of the two M. milfordi but not in the larger nor in M. maculata. From the illustrations in Norman (1934) there is a strong suggestion of marked differences in the shape of the head in M. maculata and A. tricholepis but this is caused by illustrating the largest available example of the former species and the smallest of the latter. Figure 2 gives some idea of the changes of head shape that may occur in a species with an increase in size. = at eS € << i \< 2 at po) Ficure 2. Head shapes of various specimens of the genus Mancopsetta redrawn from various sources (not to scale). A. M. maculata of 238 mm. total length (After Norman, 1934). B. M. maculata of 134 mm. total length (After Gunther, 1880). C. M. milfordi of 334. mm. total length. D. M. slavae of 63 mm. total length (After Andriashev, 1960). E. F. M. slavae of 56 mm. total length (After Andriashev, 1960). M. tricholepis of 100 mm. total length (After Norman, 1930). 186 ANNALS OF THE SOUTH AFRICAN MUSEUM From the above it is evident that there is only one important and constant difference between the two genera Mancopsetta and Achiropsetta, viz. the type of spinules present on the scales. At the same time, however, there are several clear points of similarity between A. tricholepis and M. milford: and again between A. slavae and M. maculata. It is extremely probable that the presence of vertically projecting spines in Achiropsetta is a larval or juvenile character as similar spines occur in many bothid larvae (Kyle, 1913). Andriashev (1960) holds a similar view and has stated ‘It is very probable that the peculiar prickliness of the body of Achiropsetta (that is, the strongly developed, vertically projecting spines) can be considered as a larval character of a caenogenetic nature’. He also noted the similarity in fin counts between A. slavae and M. maculata, as well as the fact that these two species had the most similar distribution. He concluded, however, that the specimens of A. slavae could not be assigned to the genus Mancopsetia since in the latter genus the body is not transparent and the scales do not have the vertically projecting spinules. Andriashev further states that it is not possible to explain these in terms of development, as the difference in size between the smallest M. maculata and the largest A. tricholepis is only 29 mm. The greatest similarities are, however, between M. milfordi and A. tricholepis, where the minimum difference between the two species is 229 mm., and between A. slavae and M. maculata, where the difference is 71 mm. While it is not possible at this stage in our knowledge of these fishes to suggest that A. tricholepis is actually the juvenile stage of M. milfordi or A. slavae that of M. maculata, it is suggested that for the reasons given above, and bearing in mind that these four species, in lacking pectoral fins, form a unique group within the family Bothidae, the species should not be separated into two genera but should rather be united into one genus, Mancopsetta. The differences between the species of the former genus Achiropsetta and those of Mancopsetta being far more likely due to growth rather than major genetic differences. The generic definition of Mancopsetta will, however, have to be modified from that given by Norman (1934), not only to include the species formerly placed in the genus Achiropsetta, but also the new species M. milfordi. Genus MANCOPSETTA Lepidopsetta (non Gill, 1864) Gunther, 1880, p. 18. Mancopsetta Gill, 1881. p. 373. Achiropsetta Norman, 1930. p. 361. Body fairly elongate, compressed and sinistral. Eyes large, close together and with the upper parts of each eyeball densely scaled. Lower eye a little in advance of the upper. Mouth of moderate size not reaching farther back than a point level with the posterior edge of the lower eye, maxillary narrow, not expanded behind. Jaws and teeth about equally developed on both sides. A small fleshy growth over the front tip of maxilla. Teeth small, conical and usually uniserial; vomer toothless. Few gill-rakers, those present being short. A NEW SPECIES OF FLATFISH, MANCOPSETTA MILFORDI 187 Dorsal fin starting far forward on head. All fin rays simple, scaled. Pelvic fin of eyed side may or may not be posteriorly deflected to the left. No true pectoral fins but a fin bud may be present in small specimens. Lateral line on both sides single, straight and well developed. Type species Lepidopsetta maculata Gunther, 1880. The genus contains four species: M. maculata (Gunther) 1880. M. tricholepis (Norman) 1930. M. slavae (Andriashev) 1960. M. milfordi sp. n. DIsTRIBUTION Andriashev (1955) has discussed the distribution of these fishes and has shown that they are known from a few specimens found over a wide area of the Southern ocean. The following are the only published locality records: M. maculata. This species is known from three specimens, all caught by bottom trawling in deep water— Marion Island: 46° 43’ S. 38° 5’ E. 580 m. (Gunther, 1880). Falkland Islands: 45° 45’ S. 59° 35’ W. 311-247 m. (Norman, 1937). South Georgia: 53° 48’ S. 35° 57’ W. 411-401 m. (Norman, 1938). M. tricholepis. This species is known from only two examples taken by bottom trawling in shallow water — Tierra del Fuego: 53° 00’ S. 68° 06’ W. 22-20 m. (Norman, 1930). Falkland Islands: (No details available) (Norman, 1937). M. slavae. Four specimens of this species are known and all were caught in midwater using an Isaacs—Kidd midwater trawl— Wilkes Land: 64° 51’ S. 114° 17’ E. 725 m. cable (Andriashev, 1960). (Antarctic) 63° 50’ S. 116° 25’ E. 1,100 m. cable (Andriashev, 1960). 64° 22’ S. 121° 08’ E. 1,100 m. cable (Andriashev, 1960). 64° 10’ S. 127° 46’ E. 1,100 m. cable (Andriashev, 1960). M. milfordi. Known from only two specimens both taken by bottom trawl in deep water— Cape of Good Hope, west of Cape Town. 550 m. Cape of Good Hope: 33° 40’ S. 17° 30’ E. 675 m. Some of these records are very widespread, especially M. maculata and suggest that these fishes are more common than the small number of known records would suggest. This is undoubtedly due to the very small amount of trawling that has been undertaken in the Southern ocean. More collecting would be very useful, as a good set of growth stages would certainly show whether M. slavae and M. maculata are in fact growth stages of the same species, and likewise with M. milfordi and M. tricholepis. 188 ANNALS OF THE SOUTH AFRICAN MUSEUM ACKNOWLEDGEMENTS I am grateful to Professor J. L. B. Smith of Grahamstown, Dr. A. P. Andriashev of Leningrad, and Mr. P. R. Sloan of La Jolla for help in obtaining literature; to the Trustees of the British Museum (Natural History) for the loan of valuable material for comparative purposes; to Messrs. Irvin and Johnson (Pty.) Ltd. for presenting these two interesting specimens to the South African Museum; and to Dr. F. H. Talbot and my wife, Mary-Louise Penrith, for reading the manuscript. The Trustees of the South African Museum are grateful to the Council for Scientific and Industrial Research for the award of a grant to publish this paper. SUMMARY A new species of bothid, Mancopsetta milfordi (Pisces: Bothidae), is described from deep water off the Cape of Good Hope. Four species of bothids are known which lack pectoral fins. They have been placed in two genera, Mancopsetia and Achiropsetta. It is shown that the two genera exhibit a marked overlap in characters and can be divided on only one character, which is probably a juvenile feature. The genus Mancopsetta is redefined to include all four species. REFERENCES ANDRIASHEV, A. P. 1960. Families of fishes new to the Antarctic. 3. Pelagic young of flatfish (Pisces, Bothidae) off the Antarctic coast. Zool. Zh. 39: 1056-1061. Git, T. 1881. Account of recent progress in Zoology. Rep. Smithson. Instu, 1880: 331-390. GunTHER, A. 1880. Report on the shore fishes. Ref. Voy. Challenger 1873-6 1(6): 1-82. Kyte, H. M. 1913. Flatfishes (Heterosomata). Rep. Danish oceanogr. Exp. medit. 1908-10 2 (At). Norman, J. R. 1930. Oceanic fishes and flatfishes collected in 1925-27. Discovery Rep. 2: 263-370. Norman, J. R. 1934. A Systematic monograph of the flatfishes Heterosomata I. London, British Museum (Nat. Hist.). Norman, J. R. 1937. The coast fishes II. The Patagonian region. Discovery Rep. 16: 3-150. Norman, J. R. 1938. The coast fishes III. The Antarctic zone. Discovery Rep. 18: 3-104. Plate III Ill / Ann. S. Afr. Mus., Vol. XLV adAyojoyy zpofjru pyjasqoouvywy INSTRUCTIONS TO AUTHORS MANUSCRIPTS In duplicate (one set of illustrations), type-written, double spaced with good margins, including TABLE OF CONTENTS and Summary. Position of text-figures and tables must be indicated. ILLUSTRATIONS So proportioned that when reduced they will occupy not more than 4? in. x 7 in. (74 in. including the caption). A scale (metric) must appear with all photographs. REFERENCES Authors’ names and dates of publication given in text; full references at end of paper in alphabetical order of authors’ names (Harvard system). References at end of paper must be given in this order: Name of author, in capitals, followed by initials; names of joint authors connected by &, not ‘and’. Year of publication; several papers by the same author in one year designated by suffixes a, b, etc. Full title of paper; initial capital letters only for first word and for proper names (except in German). Title of journal, abbreviated according to World list of scientific periodicals and underlined (italics). Series number, if any, in parenthesis, e.g. (3), (n.s.), (B.). Volume number in arabic numerals (without prefix ‘vol.’), with wavy underlining (bold type). Part number, only if separate parts of one volume are independently numbered. Page numbers) first and last, preceded by a colon (without prefix ‘p’). Thus: Suiru, A. B. 1956. New Plonia species from South Africa. Ann. Mag. nat. Hist. (12) 9: 937-945. When reference is made to a separate book, give in this order: Author’s name; his initials; date of publication; title, underlined; edition, if any; volume number, if any, in arabic numerals, with wavy underlining; place of publication; name of publisher. Thus: Brown, X. Y. 1953. Marine faunas. 2nd ed. 2. London: Green. When reference is made to a paper forming a distinct part of another book, give: Name of author of paper, his initials; date of publication; title of paper; ‘In’, underlined; name of author of book; his initials; title of book, underlined; edition, if any; volume number, if any, in arabic numerals, with wavy underlining; pagination of paper; place of publication; name of publisher. Thus: SmirH, C. D. 1954. South African Plonias. In Brown, X. Y. Marine faunas. 2nd ed. 3: 63-95. London: Green. SYNONYMY Arranged according to chronology of names. Published scientific names by which a species has been previously designated (subsequent to 1758) are listed in chronological order, with abbreviated bibliographic references to descriptions or citations following in chronological order after each name. Full references must be given at the end of the paper. Articles and recommendations of the International code of zoological nomenclature adopted by the XV International congress of zoology, London, July 1958, are to be observed (particularly articles 22 and 51). Examples: Plonia capensis Smith, 1954: 86, pl. 27, fig. 3. Green, 1955: 23, fig. 2. When transferred to another genus: Euplonia capensis (Smith) Brown, 1955: 259. When misidentified as another species: Plonia natalensis (non West), Jones, 1956: 18. When another species has been called by the same name: [non] Plonia capensis: Jones, 1957: 27 (= natalensis West). "Wi NAN 9088 01206 5876