BuZl.zooZ. SUr1). , 6 (1-3) : 279-281, 1984

ON THE OCCURRENCE OF COSUATIS (HAM.) IN KAZIRANGA NATIONAL PARK, (PISCES : )

RAJ TILAK* AND J. P. SATI Z oologicaZ Survey of India, Shi,llong.

ABSTRAOT Orrichthys cosuatis (Hamilton), a hitherto unrecorded speoies from North-eastern part of India ha.s been found distributed in Kazimnga. Nationa.l Pa.rk, Assa.m. This extends the range of distribution of this species to Eastern India and adds evidenoe to Sa.tpura Hypotbesis of migration of fishes.

INTRODUCTION SYSTEMATIC ACCOUNT Hamilton (1822) described Oyprinus cos'Ua­ Oreicbthys cosuatb (Ham.) ti8 from Kosi River and Day (1878) reported, (Fig. 1) the occurrence of this species in "Bengal, through North-western Province, the Deccan 1822. Oyprinus cosualis Hamilton, Fish , and Bombay and down the Western Coast as pp. 338, 392 (Type-locality: Kosi River). as low as Cottayam in Trivandrum." The 1878. Barbus eosuatis: Da.y, Fish India, p. 581, pI. OXLIV, Fig. 1. material of this species was also studied by Hora (1937a, b, 1942) and Hora and Nair 1937. Oreiehthys cosuatis : Hora, Bee. Indian Mus., 39 (4) pp. 321-323. (1941) from Madhya Pradesh and Peninsular BIll, D. 111/8, P 1/13, V 1/8, A 11/5, O. 19 India. Hora (1937 a) clarified the systematic position of Oyprinus cosuatis and placed it Length of head 4.59 in total length (T. L.) under the Oreichthys Smith although and 3.42 in standard length (S. L.), length of Day (1878) considered it under Barbus. This snout 3.4 in head length; length of snuut 1.4 species was not so far reported from North­ in eye diameter; eye diameter 2.44 in head eastern part of India. Recently, a specimen length; interorbital width 3.36 in head of Oreichthys c08uatis, from Kaziranga National length; height of the body 5.2 in T. L. and Park, has been studied and this report extends 3.87 in S. L.; length of caudal peduncle 6.5 the distribution of this species to North­ in T. L. and 4.84 in S. L.; height of caudal eastern region of India. Because of its interes­ peduncle 10.26 in T. L. and 7.63 in S. L. ; ting features and rather rare occurrence of height of caudal peduncle 1.58 in length of this species, it is important to give a brief­ caudal peduncle; length of longest dorsal ray description of material from North-eastern 4.59 in T. L. and 3.42 in S. L.; longest anal region. ray 6.5 in T. L. and 4.84 in S. L.; base of

·Fxoesenb Adcb:ess: Zoologica.l Survey of India, Debra-Dun. 280 Bulletin oj tke ZoologicaZ Sur'Vey of 1ndiu dorsal 1.7 in longest dorsal ray and base of is only one specimen, it is for the time being anal 2.73 in longest anal ray. kept under Oreicktl"Y8 c08uatis which is most The body is somewhat lanceolate. The close to it. upper ray is slightly longer than the lower A study of more material from the same and the mouth is small. The' dorsal fin origi­ locality and its comparison with that from nates slightly nearer the tip of snout than the other parts of India should give a clearer base of caudal and opposite the half po~terior texonomic position of this specimen. of the pectoral fin. The longest ray of the dorsal fin is a little smaller than the depth of The distribution of Oreichtkys c08uatis is the body below it. The scales along the quite interesting. It has earlier been recorded lateral-line are larger than those of rest of the from West Bengal, Madhya Pradesh, Maha­ body. The base of each scale has a dark rashtra, Karnataka and Kerala on the one tinge. There is a black band on the upper side and Thiland in the far east on the other half of the first three branched rays. A hand. The present report of this species lighter band along the lower half of the dorsal from Assam indicates that this species is rays present. A dark band along the anal found all along the route of migration of rays present. fishes according to Hora's Satpura Hypothe-

10 ?'Y}1)11 .

Fig. 1. (Ham.) from Kazita.nga. National Park, Assam.

Distribution: Assam, West Bengal, Madhya sis. The occurrence of this spices in Assam Pradesh, Mabarashtra, Karnataka, Kerala, is, therefore, very important from zoogeo­ Pakistan, Bangladesh, . graphic point of view and adds another evi­ Remarks: The present specimen differs dence to Satpura Hypothesis of migration of from the description of this species given by fishes. Day (1878: 581) in having shorter height of ACKNOWLEDGEMENT the dorsal, lesser height of the body, origin The authors feel grateful to Dr. B. K. of the dorsal fin nearer the tip of snout and Tikader, Director, Zoological Survey of India, presence of lower labial fold etc. Since there Calcutta for all facilities and encouragement. TltAK et til: On Oreiohth1Js e08uatis 281

REFERENCES tic position of Oyprinu8 e08uati8 Hamil­ DAY, F. 1878. The Fishes of India. London: ton. Ree. Indian MU8., Calcutta, 39 (4) : 581. 321-323. HAMILToN, F. 1822. An account oj the Fishe8 HORA, S. L. AND NAIR, K. K., 1941. Fishes found in the river Gange8 and its tributa­ of the Satpura range, Hoshangabad ries. Edinburgh: i-vii, 1-405, 39 pis. District, Central Provinces. Bee. Indian HORA, S. L. 1937 a. Notes on fishes in the MU8., 43 (3): 361-373. Indian Museum XXVIII. On three collections of fish from M ysore and HORA, S. L. 1942. A list of fishes of the Coorg. South India. Rec. Indian MU8., Mysore State and of the neighbouring Calcutta, 39 (1) : 5-28. Hill Ranges of the Nilgiris, Wynad and HORA, S. L. 1937b. Notes on fishes in the Coorg. Bee. Indian Mus., 44 (2): Indian Museum XXX. On the systema- 193-200.

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