}jull. zoo/. Surv. tndia, 8 (1-3) : 29-31, 1981

ON A NEW OF (PISCES: SILUROIDEA, FAM1L'I : SILURIDAE) FROM NAMDAPHA WILDLIFE SANCTUARY, ARUNACHAL PRADESH, INDIA

A. K. DATTA, R. P. BARMAN & K. C. jAYARAM

Zoological Survey of Illdia, Calcutta.

ABSTRACT In the faunistic survey of the Namdapha area Tirap district, Arunachal Pradesh, India, a new fish of the family Siluridae, l(ryptopterus Bleeker was found. )(ryptoplerus i"dicus sp. nov. is described here and its zoogeographical affinities are discussed.

INTRODUCTION bill point, Namdapha river, Namdapha Wild­ life Sanctuary, Arunachal Pradesh, India. Coil. An interesting collection of fish com­ Dr. S. Biswas & S. Saha. Date 18.4.81. prising 235 examples were collected during the survey and one example of of the genus Kryptopterus (Family: Siluridae) was it Kryptopterus found to be new, is named as DIAGNOSIS indicus. rudimentary with one minute MATERIAL ray, adipose dorsal absent. Anal fin long (Fig. 1) with 88 rays, continuous with caudal fin. Holotype: 218 mm. in standard length. Eyes subcutaneous above the angle of mouth. Reg. No. Z. S. I. F. F. 1699. Locality-Horn Vent with a papilliform appendage.

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. 1 Lateral view of [{ryptopterus indicus Datta, Barman and Jayaram. Fli· • Bulletin of the ZoologIcal SurveY of lad'a

DESCRIPTION one ray, ventral rays seven, anal fin confluent with the base of caudal. Dorsal fin rudimentary with one minute ray and adipose dorsal fin absent, body laterally compressed beyond vent. Abdomen rounded, head depressed dorsoventrally flattened. Measurement in mm Depth of body 5.45 in standard length. Standard length 218 Length of head 5.89 in standard length, its Depth of body - 40 width 1.32 in its length. Anterior part of Length of head - 37 back convex, posterior part concave. Eye Height of head - 23 nearer to cleft of mouth, 9.25 in head, 3.25 Width of head - 28 in snout, 4.25 in interorbital width. Jaws Length of snout - 13 subequal, maxilla over hanging, gape of Diameter of eye -4 mouth extending near to the anterior border Interotbital width - 17 of eye. Maxillary barbel tip filamentous, 1.48 Lateral line - Present in head length, reaching beyond posterior Dorsal fin - rudimen- margin of pectoral fin. Mandibular barbel tary with half the length of head. Caudal fin with one ray 17 rays shorter than head. Anal 88 rays. Pelvic ihorter than pectoral, with 8 rays. Length of pectoral - 24 Distance from anterior origin of pelvic to base of caudal - 150 Anal fin rays - 88 (3/85) AFFINITIES Distance from vent to anal - Over- The new species Kryptopterus indicus is lapping closely allied to K. limpok Bleeker. Smith Pectoral fin rays -12 (1/11) (1945) differentiated eight species of Anal length - 135 Kryptopterus found in Thailand. These are Vent - papillated K. apogon (Bleeker), K. bicirrhis (C. & v.i, K. cittis-like bleekeri GUnther, K. cryptopterus (Bleeker), Length of Maxillary barbel - 55 K. hexapterus (Bleeker), K. limpok (Bleeker), Length of Mandibular barbel - 18 K. (Bleeker), K. moo rei Smith. Brancheostegal ray - 12 The differences between the new species and Ventral fin rays - 8(1/7) the allied species (K. limpok) are in respect Lenth of ventral fin - 13 to the maxillary barbel reaching posterior margin of pectoral fin versus maxillary barbel reaching posterior fourth of anal fin, mandi­ ZOOGEOGRAPHY bular barbel half the length c;>f head versus mandibular barbel longer than head, anal fin The occurrence of Kryptopterus indicus in rays eighty eight versus anal rays seventy. Namdapha area, with its closest allies in The common characters are dorsal fin having Thailand is of zoogeographical interest. DATTA: New species of Kryptopterus from Namdapha 31

Namdapha river originates and drains North­ REFERENCES west slope of Patkai Bum, thereafter flowing HORA, S. L. 1937. Geographical distribution westward to join the Brahmaputra river. The of Indian freshwater fishes and its head waters of Namdapha is close to bearing on the probable land connec­ Chindwin drainage having a common catch­ tion between India and adjacent coun­ ment area. tries. Curr. Sci. 5 : 351-356. HORA, S.L. 1949. Dating of period of migra­ Hora (1939) postulated that the fish fauna tion of the so-called Malayan element of peninsular India has the so called Malayan in the fauna of peninsular India. Proc. element and there exists affinities at the nat. Inst. Sci. India, 15 : 345-351. generic level among th:e fauna found in Malaya and peninsular India. Hora thought HORA, S. L. 1950. Horas Satpura hypothesis. that the Malayan elements dispersed west­ Curr. Sci. 19 : 346-370. ward along the Garo-Rajmahal hills and HORA, S. L. et al 1949. Symposium on Sat­ reached peninsular areas through the Western pura hypothesis on the distribution of ghats. Jayaram (1974) showed that the Malayan fauna and flora to peninsular ichthyofauna of peninsular India was dis­ India. Proc. nat. inst. Sci. India, 15: persed by several intrusions of the so-called 309-422. Malayan element that was derived from Indo­ JAYARAM, K. C. 1974. 'Ecology and distribu­ China. He suggested that the maior faunal tion of freshwater fishes, amphibia, dispersal centre was the Yunnan plateau and reptiles', pp. 517-84 in Ecology and it was the epicentre of dispersal in all Biogeography in India, Ed. M. S. Mani, directions. Monographic BiolOgical, 23, Dr W. Junk, The Hague, 773 pp. Considering the above views, it may be MANI, M. S. 1974. 'Physical features and said that Kryptopterus indicus is one such off­ Biogeographical evolution in India', shoot of the Indo-chinese element in the pp. 11-58 and 698-722 in Ecology and Indian fauna. biogeography in India, Ed. M. S. Mani, Monographiae Biological, 23, Dr W. Junk, The Hague, 733 pp. MENON, A. O. K. 1973. 'Origin of fresh­

ACKNOWLEDGEMENT water :fish fauna of India', Curro Sci., 42 (16) pp. 533-556. The authors are graterul to the Director, SMITH, H. M. 1945. The freshwater fishes Zoological Survey of India for giving the of Siam or Thailand. Bull. U. S. natn. opportunity to do this work. Mus., Washington, 188: 302 .. 329.