(Teleostei: Cypriniformes: Cyprinidae), a new freshwater fish from the Brahmaputra drainage, India

: Barilius torsai is described from the Torsa, a tributary of Brahmaputra River system in West Bengal, India. The new species is distinguished from all its congeners by the presence of a complete lateral line with 52–53 scales, 29 pre-dorsal scales, pectoral fin notched, two well-developed pairs of barbels (rostral and maxillary), length of rostral barbel slightly larger than maxillary, which reaches the orbit. Tubercles on snout and lower jaw absent, 9–11 blue vertical bars along the body, dorsal fin hyaline with dark pigment concentrated along lower two-third of the dorsal-fin rays. Abstract बरीलियस

During an ichthyological survey in the Torsa, a tributary of the Brahmaputra River during July and November 2015, a total of 83 individuals of a Barilius species were caught by cast net of mesh size 15-20 mm at Jaldapara, Alipurduar District, West Bengal, India.Examination of the collected specimens in July 2015 and detailed re-examination in November 2015 following standard literature (Jayaram 2010;Arunkumar & Singh 2000;Nath et al. 2010;Dishma & Vishwanath 2012;Knight et al. 2015) revealed that 11 of the 83 specimens could not be assigned to any of the known species.The new species is described herein as Barilius torsai.

MATERIALS AND METHODS
Measurements were made with digital caliper with an accuracy of 0.1mm.Counts and measurements were made on the left side of the specimens wherever possible and based on standard methods following Dishma & Vishwanath (2012)

Diagnosis
Barilius torsai is distinguished from all other species of Barilius by a combination of the following characters: lateral line complete with 52-53 scales, 29 pre-dorsal scales, pectoral fin notched, two well-developed pairs of barbels (rostral and maxillary), body with 9-11 blue vertical bars, dorsal fin hyaline with dark pigment concentrated along lower 2/3 rd of dorsal-fin rays.

Description
See Table 1 and Supplementary 1 for morphometric characters and image 1 for general appearance.Body shallow, its depth about one-fourth standard length (SL), laterally compressed with ventral profile more convex than the dorsal profile.Caudal peduncle long, narrower near the caudal base.Head small and compressed, length about one-fourth SL, snout slightly blunt.Mouth oblique, angle of gape not reaching vertical from the anterior margin of the orbit.No symphysial process in the lower jaw.Eyes large, situated in the anterior half of the head, diameter about one-fourth head length (HL).Nostrils closer to anterior margin of eye than the snout tip.Two pairs of well-developed barbels (rostral and maxillary), length of rostral barbel slightly larger than maxillary, which reaches the orbit.Tubercles on snout and lower jaw absent.
Dorsal fin with two simple and seven branched rays, its origin posterior to the pelvic-fin origin, and closer to the caudal-fin base than tip of the snout.Pectoral fin with two simple and 11 branched rays, not reaching the pelvic-fin base, notched after third (between third and sixth ray).Pelvic fin with two simple and seven branched rays, its origin closer to the anal-fin than pectoral-fin origin, posterior tip not reaching anus/anal fin origin, muscular pad at base present.Anal fin with two simple and eight branched rays, its origin just below base of the last dorsal fin ray.Caudal fin deeply forked, lobes equal, with 17 principal rays.Scales cycloid and small.Lateral line complete, slightly curved, running along lower half of the body and passing almost through middle of the caudal base, with 52-53 scales in the lateral-line row up to the end of the caudal base.Scales in transverse line on body 11/1/5 between dorsal fin origin and pelvic fin base.29 pre-dorsal scales.

Colour
In live and fresh specimens, dorsum appears greyish, sides and belly silvery.Body with 9-11 blue vertical bars, three to five anterior bars almost reaching lateral line, number of bars on either side of the body unequal.Pectoral, pelvic and anal fin hyaline.Caudal fin hyaline, with black margin on fork edges.Dorsal fin hyaline with dark pigment on rays, concentrated along lower twothird of dorsal-fin rays.In preserved specimens, silvery colouration disappears and all dark pigment in fins and body bar turns black.Dorsum appears black and ventral areas creamy.

Etymology
The specific name refers to the Torsa, type locality of the species, and a tributary of the Brahmaputra River System.An adjective.

Distribution
Presently known only from the Torsa River in West Bengal, India (Figure 1, Image 2).
A new species of Barilius adds to our understanding of the diversity of freshwater fishes of the Torsa River and the eastern Himalayan ecoregion.New discoveries such as this also shows that our understanding of diversity and conservation of freshwater fishes of this region needs to be improved and more exploratory surveys are required.

Barilius torsai sp. nov. (Image 1)
. Colour pattern was recorded from fresh and preserved (10% formalin) specimens.Voucher specimens are deposited in the Museum of the Zoological Survey of India (ZSI), Kolkata and at the ICAR-Central Inland Fisheries Research Institute (CIFRI), Barrackpore.