Gangetic Fishes."
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SYSTEMATIC POSITION OF SILUROIDS IN HAMILTON'S " GANGETIC FISHES." By SUNDER LAL HORA, D.Se., F.R.S.E., F.R.A.S.B., F.Z.S., F.N.I., Director, Zoological Survey of I ndia, Calcutta. Since 1933, I have been engaged in a revision of the Siluroid fishes of India, Burma and Ceylon and have so far published notes on the genera Amblyceps Blyth,1 Akysis Bleeker,2 qlyra McClelland,s Wallago Bleeker,' H eteropne'Ustes MUller, 5 Olarias Gronovius,6 Silurus Linnaeus,7 CalUch, ous Hamilton,8 Gagata Bleeker, 9 Batasio Blyth, 10 Silonopangasitl8 Hora,11 Pseudeutropius Bleek~r,12 Proeutropiichthys Hora,ls and Ailia Gray.14 In a series of articles on the' Game Fishes of India " detailed revisions are given of the genera Eutropiicht~ys Bleeker,15 Olupisoma Swainson16 Silonia Swainson,17 Pangasias Ouvier and Valenciennes, 18 Bagarius Bleeker19 and Wallagonia Myers.20 These studies were interrupted owing to my deputation for a period of 5 years to Bengal in May 1942 t.o organise a fish eries department there, but the earlier work had shown that great difficulty was experienced in elucidating the precise systematic p'Jsition of some of the SilurQid fishes described by Hamilton21 in his monumental work" Gangetic Fishes." The circumstances under which this work was published could not but lead to insufficient characteriza tion of a. number of species which resulted in great confusion in later taxonomic works on Indian freshwater fishes. An aid to the study of ---------------------------------------------------------1Hora, S. L., Rec. Ind. Mus. XXXV, pp. 607-621 (1933). I Rora, S. L., ibid. XXXVIII, pp. 199-202 (1936). a Hora, S. L., ibid. - XXXVIII, pp. 202-207 (1936). 'Rora, S. L., ibid. XXXVIII, pp. 207-208 (1936). 6 Rora, S. L., ibid. XXXVIII, pp. 208-209 (1936). e Rora, S., L. ibid.r XXXVII, pp. 347-351 (1936); XLIII, pp. 112.] 14 (1941). 7 Rora, S. L., ibid. XXXVIII, pp. 351-356 (1936). B Rora, S. L., ibid. XXXVIII, pp. 256-361 (1936). • Rora, S. L., ibid. XLIII, pp. 9-27 (1941). 10 Rora, S. L., ibid. XLIII, pp. 28-42 {1941). 11 Rora, S. L., ibid. XLIII, pp. 97-100 (1941). 11 Hora, S. L., ibid. XLIII, pp. 100-105 (1941). J8 Hora, .S. L., ibid. XLIII, pp. 105-110 (1941). 1& Rora, S. L., ibid. XLIII, pp. 110-112 (1941). 16 Rora, S. L., Journ. Bombay Nat. Hi8t. 80c. XXXIX, pp. 431-446 (1937). 18 Rora, S. I~., ibid.. XXXIX, pp. 659-678 (1937). 17 Rora, S. L., ibid. XL, pp. 197-147 (1938). 18 Rora, S. L., ibid. XL, pp. 355-366 (1938). 18 Rora, S. L., ibid. XL, pp. 583-593 (1939). 10 ROTa, S. L., ibid. XLI, pp. 64-71 (1939). 21H&milton, F., A.n A.ccount 01 the Fi8ku found in the River Gange8 and it, branche, (Edinburgh: 1822). [ 63 ] 64 Records of the Indian Museum. [VOL. XLVI, Hamilton's "Gangetic Fishes" was publishedl to bring together all scattered data concerning this work in one place but no attempt was made to elucidate the systematic position of the various species described therein. The object of this note is to define the specific limits of the ~iluroids in Hamilton's "Gangetic Fishes" and to give up-to-date references to literature in support of the views expressed herein. Indian species of some of the genera, such as Arius euvier & Valenciennes (=Tackysurus Lacepede), have not yet been revised but there appears to have been little or no confusion regarding their systematic position or specific limits. I wish to record here my thanks to Dr. K. S. Mis~a in looking up records of distribution of various species and for putting up relevant literature connected therewith. Of the 49 species of Cat-fishes (Siluroidea) described by Hamilton, 41 are found to be valid according to modern standards. The remaining eight were either based on deformities, such as Macropteronotus jagur, or on variations in colour, fin rays, etc., such as Silurus pabda, S. canio, S. duda, S. ckeckra, Pimelodus chandrarnara, P. botius, P. urUQ;, etc. Of the 41 valid species, six have been relegated to the synonynlY of earlier species, but it is worthy of note that Hamjlton himself had pointed out the affinities of his species to earlier know~ forms. For example, in describing Macropte'lonotus magur (=Olarias batrachus), he observed :- " This species, if it be distinct, has the utmost affinity to the M acroptercmotu, . batrackus of La Cepede, (Bi8t. de8 Poia801'ta, Tome V, page 84), or the Siluru8 batrackus of Bloch, (1enth. Tome XI, page 34, PI. CCCLXX. fig. 1). The fish, indeed, described by these a.uthors differs from oura in the number of rays supporting i~s fins, but, owing to the thickness of the skin, no grea.t reliance can be placed on the accuracy of this mark; and besides, these authors desoribe their fish as of an uniform brown colour, and state, that the priokle of each pectoral fin is strongly indented behind." It will thus be seen that number of rays in the fins, colouration and nature of pectoral spines influenced Hamilton in separating his s-pecies from Olarias batrackus. I2 have already shown the great variability of certain taxonomio characters in this species and it is no wonder that Hamilton attached some importance to them in those early days. In the case of his Silurtts singio, he observed :- "This fish, if really different, is most nearly allied to the 8iluru8 /088ilis of Blooh, (Ichth. Tome XI, p. 36, Pl. CCCLX, fig. 2), and La Cepede, (Hist. dea Poissons, Tome V, p. 74). Their fish is of a ohocolate colour, its lateral lines ascend towards the shoulder; and the number of rays in its fins is somewhat different from that of the fish in Bengal. The most marked differences, however, to judge from the figure of Bloch, atA, that he ;represents th~ prickles of the pectoral fins as slender, and without barbs." lHora. S. L., Mem. Ind. Mu,. IX, pp. 169-192 (1929). tHora, S. L., Bee. Ind. MUI, XXXVIII, pp. 347-351 (1936). 1948.] S. ,L. BORA: Siluroids in " Gangetic Pishes. H This shows how incomplete description and bad delineations of earlier species influenced him to propose new species. Similarly he pointed out very strong resemblance of his Silurus canio to S. bimaculatus of Bloch; of S. boalis to Wallago of Dr. Russell and of Pimelodus urua to P. atherinoides of Lac~pp.de. All this shows that he was a very careful worker on the systematics of fishes. According to our present-day knowledge, Hamilton's Siluroids can be arranged in the following systematic ordf'! :- Olassification of Siluroids 'l,n Hamilton's "Gangetic Fishes. " Family CLARnDAE. 19. Mystu8 menoda (Ham.). 1. Claria8 batrachtl,8 (Linn.). 20. M y8tus cavasiu8 {Ham.~ 21. Mystus aor (Ham.). Family HETEBOPNEUSTIDAE. 22. Ramo, rama (Ham.): 2. Beteropnetl,ste8 j08silis (Bl.). 23. Rita rita (Ham.). Family SILURIDAE. 'Family AMBLYCEPITIDAl!:. 3. Ompok bimac'Ulat'U& (BZ.). 24. A mblyceps manUoill (Ham.). 4. Ompok pabo (Ham.). Family SISORIDAE. 6. Wallagonia attu (Bl.). 25. Bagariu8 baga."1·U& (Ham Family CBAOIDAE. 26. Gagata cenia «Ham:). 6. Cltaca chaca (Ham.). 27. Gagat gagata (Ham.). f Family PLOTOSIDAE. 28. Gagata ~'iridescen8 (Ham.). 7. PlotO&'U8 caniu8 (Ham.) 29. Gagata ,,,angra (Ham.). Family SORILBEIDAE. 30. GZyptothorax telchitta (Ham.). 8. Ailia coila (Ham.). 31. GZyptothorax cat'ia (Ham.). 9. Clupisoma garua (Ham.). 32. Eretkiste8 (1) hara (Ham.). 10. Eutropiichth1l8 vacha (Ham.). 33. Eretkistes (1) conta (Ham.). 11. EutropiichthY8 m'Urius (Ham.). 34. Sisor rabdophor'U8 (Bam.) 12. P,eudeutropius atheri11.oides (Bl.). F&"mily TACHYSURIDAE. 13. Bilonia silondia (Ham.). 35. BatrachocephaZu8 mino (Ham.) 14. Pangasius pangasiu8 (Ham.). 36. Tachysurus ariU8 (Ham.). Family BAGRIDAE. 37. Tachysuru8 gagora (Ham.). 15. Batasio bata8io (Ham.). 38. Tachysurus jatiu8 (Ham.). 16. Bata8io tengana (Ham.). 39. TachY8urus nenga (Ham.l. 17. M1IstfJ,! fJiliatu8 (Ham.). 4,0. 'TackY8uru8 sagor (Ham.). 18. Mt/8tu8 gulio (Ham.). 41. Tach1J8uru8 80na (Ham.). Table shouyiflg Sy'tematic Position of Silu'I'oids in Hamilton's " G'.ltlgetic Fi,helt." No. ~&tlJ.e and Referflnce in Locality and Local Name , Locality and Local Current Scientific Name and Distrilution. U Gangetic Fishes.') in " Gangetic Fishes. " Names in Original Notes. Reference. PlatystaCtL8 chaca, p. 140, North-East Bengal; Fluviis et stagnis Ben- Ckaca ckaca (Hamilton); India, Burma, Malacca, pl. xxviii, fig. 43. Ohaw. gala; Okalllca. ,,\\'eber & de Beaufort, Fish. Malay Peninsula, Banka, Indo-Au8tral. II, p. 246, Borneo and Sumatra. fig. 99 (1913). 2 Plotosu8 Canitl8, p. 142, Southein Bengal; Kani Fluviis Bengalainferioris; Pl(tc~'U8 cani'U8 Hamilton; Ceylon, India, Burma- pl. xv, fig. 44. magur. Kaanee .Maagoor. Weber & de Beaufort, ibid. Siam, Nalaya and Indo- II, p. 227. Australian Archipelago, Canton (China). I M acropteronot'I.UJ Jag'll', Stagnis BengalI, inferioris; Olarta s bafrw ntls (Linnaeus) ; Ceylon, India, Burma, p.145. Jagur Lukipura. Bora, Ree. Ind. M'U8. Malaya, Dutch East XXXVIII, p. 348 (1936). Indies, Philippines, French Indo-China. and Hongkong. • Macropteronotu8 mag'Ur, Mag'Ur Stagnis et fopis Bengala Ditto. Ditto. p. 146, pl. xxvi, fig. 4.5. inferioris in luto Post. 6 8iluf''U8 8i'llgio, p. 147, Singgi Stagnorum et fosearum Heteropnf'U8te8 /o8sili8 (Bloch); Ceylon, India, :Burma, pl• .xxvii, fig. 46. luto; Kamacha singgi. Bora, Ree. Ind. Mus. Siam and Indo-China. XXXVIII, p. 208 (1936). Bilurfl8 (OaUickro'U8) Bengal; Pabda. Fluviis et stagnis Ben Ompok bimaculatu8 (Bloch) ; Ceylon, India, Burma, fJabda, p. 150, pl. xxv, gala. inferioris ; P aebdaa B ora., Bee. Ind. MU8. Siam, Mala.ya, Java, fig. 47. XXXVIII, pp. 356-361 Borneo, Suma.tra, o-< (1936). Smith (U. S. Nat. Chusan, Yunnan and MtUJ.