Hypselobarbus bicolor Knight, Rai, D'Souza, Philip & Dahanukar, 2016, sp. nov.
Creators: name: Marcus Knight, J. D.
name: Rai, Ashwin
name: D'Souza, Ronald K. P.
name: Philip, Siby
name: Dahanukar, Neelesh
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Actinopterygii
Cypriniformes
Cyprinidae
Hypselobarbus
Hypselobarbus bicolor

description: Hypselobarbus bicolor, sp. nov.
(Figs. 1 & 2)
Hypselobarbus pulchellus (not Day, 1870): Knight et al. (2014c, p. 5196)
Holotype: BNHS FWF 159, 20.4. 2013, 197 mm SL, Sita River, Chara, Karnataka, India, coll. Ronald D’Souza
Paratypes: ZSI/SRC F 8737, 20.4.2013, 3 ex., 107–118 mm SL, Sita River, Chara, Karnataka, India, coll. Ronald D’Souza; ZSI/SRC F 8753, 1998, 1 ex., 126 mm SL, Tunga River, Shimoga, Karnataka, India, coll. K.C. Jayaram. MKC 405, 20.4.2013, 3 ex., 124–208 mm SL, Sita River, Chara, Karnataka, India, coll. Ronald D’Souza.
Diagnosis. Hypselobarbus bicolor can be distinguished from all other species of Hypselobarbus based on the combination of the following characters: two pairs of barbels, lateral line complete with 34–36+1–2 pored scales, ½6/1/3½ scales in the transverse row; 11–12 predorsal scales; last simple dorsal ray weak, dorsal fin with 9½ branched rays, gill rakers short and simple, 4–6+11–12 on first gill arch; proximal end of fifth ceratobranchial slightly curved, with 5+3+2 teeth; overall coloration dark grey, with an ill-defined silver- or bronze-coloured band running along length of body, two scales high, on lateral-line scale-row and row above it; fins devoid of any markings; and small, closely-spaced tubercles in large males (> 150 mm SL), restricted to the tip of the snout.
Description. Morphometric and meristic data are provided in Table 1. General body shape and appearance as in Figs. 1–2.
Body deep, laterally compressed; dorsal contour ascending sharply, with a clear indentation at nape, descending gradually posterior to dorsal-fin origin; ventral profile deep, equally convex, curving up to anal-fin origin, thence sloping upward towards caudal peduncle; caudal peduncle deep, its depth almost equal to its length, concave in both dorsal and ventral profiles.
Head short, snout rounded, indented transversely anterior to nares, mouth inferior, lips thick. Barbels 4, maxillary barbel a little less than orbital diameter, rostral less than half of orbital diameter. Eyes large, placed on upper half of head, orbital diameter one-third HL.
Dorsal fin with 3 unbranched and 9½ branched rays, last unbranched ray weak. Dorsal-fin origin slightly anterior to pelvic-fin origin, midway between tip of snout and base of caudal fin. Pelvic fin with 1 un-branched and 8(7)–9(1) branched rays. Anal fin with 3 un-branched and 5½ branched rays. Pectoral fin with 1 un-branched and 15 branched rays. Pectoral and pelvic fins short, not reaching pelvic and anal fin origins respectively. Caudal fin with 19(1+9+8+1) principal rays, deeply forked.
Lateral line complete, with 34(2), 35(5) or 36(1) scales, plus 1(6) or 2(2) scales on caudal-fin base. Transverse scales from dorsal-fin origin to ventral-fin origin ½6/1/3½. Predorsal scales 11–12, circumpeduncular scales 14. Pelvic axillary scale present. Gill rakers simple, 4–6+11–12 on first gill arch; fifth ceratobranchial with 5+3+2 teeth, its proximal end curved (Fig. 3).
Coloration. In life (Fig. 2 A), overall dark grey with an ill-defined silver- or bronze-coloured band running along the length of the body, two scales high, on lateral-line scale row and row above it. Head silvery; all fins dusky grey. Formalin-fixed and alcohol-preserved specimens (Figs. 1, 2 B) dark grey with lateral band becoming white. All fins dark grey.
Etymology. The specific epithet ‘bicolor’ meaning ‘of two colours’ in Latin, a noun in apposition alluding to the predominantly black and silver coloration of this fish.
Distribution. Hypselobarbus bicolor is currently known from the Sita and Tunga Rivers in Shimoga District, Karnataka State, India (Fig. 4).
Genetic analysis. Best partition scheme for the concatenated Cytb and COI partial gene sequence data was HKY+R2 for first two codon positions of both the genes, TIM2+R3 for third codon position of Cytb and TIM3+G4 for third codon position of COI. Maximum likelihood analysis (Fig. 5) suggests that H. bicolor is a sister taxon to a monophyletic clade consisting of H. dobsoni, H. jerdoni and H. pulchellus from which it is separated by genetic distances of 7.5%, 7.9% and 7.0–7.2% respectively (Table 2).
Identity of Hypselobarbus pulchellus. It is relevant to note that some of the specimens which were used to revalidate H. pulchellus by Knight et al. (2013c) have now been included in H. bicolor. This makes it necessary to clarify the identity of H. pulchellus, especially in comparison with H. dobsoni and H. jerdoni. While the description in Knight et al. (2013c) remains valid, Hypselobarbus pulchellus is characterized by possessing the following characters: barbels 2 pairs, maxillary barbel approximately one-fourth HL, rostral less than one-fifth HL; dorsal fin with 3 simple and 9½ branched rays, the last simple ray weak; pelvic fin with 1 simple and 8 branched rays; anal fin with 3 simple and 5 ½ branched rays; pectoral fin with 1 simple and 15 branched rays; pectoral and pelvic fins short, not reaching pelvic and anal-fin origins, respectively; caudal fin with 19 (1+9+8+1) rays, deeply forked; lateral line complete, with 31–32 scales on the body and 1 scale on the caudal-fin base; scales in transverse line from dorsal-fin origin to ventral-fin origin ½5– 6/1/2½ – 3; predorsal scales 11; circumpeduncular scales 12; and 4 +12 gill rakers on the first gill arch.
Coloration. In life, dark grey above and light grey below, with a well-defined silver- or bronze-coloured band running across the length of the body, two scales high, including the lateral-line scale row and one scale row above it. All fins dark grey without any markings. Formalin-fixed and alcohol-preserved specimens are dark grey with the lateral band becoming white. The well-defined light band running along the lateral line is perceivable also in the dry-skin mount of H. pulchellus in the Natural History Museum, London (BMNH 1889.2.1.4328).
Comparison among H. pulchellus, H. dobsoni and H. jerdoni: Hypselobarbus pulchellus can be distinguished from both H. dobsoni and H. jerdoni from the well-defined silver- or bronze-coloured band running across the length of the body, two scales high, including the lateral line scale row and the scale row above it (vs. absence of the band in H. dobsoni and H. jerdoni). Dorsal fin, pelvic fin and caudal fin tips devoid of any markings (vs. distal portion of the dorsal fin black, with pelvic fin tips and caudal fin tips black in H. dobsoni and H. jerdoni). Furthermore, H. pulchellus can be distinguished by a higher lateral line scale count of 31–32+1 (vs. 29–30 + 1 scales in H. jerdoni).
description: Published as part of Marcus Knight, J. D., Rai, Ashwin, D'Souza, Ronald K. P., Philip, Siby & Dahanukar, Neelesh, 2016, Hypselobarbus bicolor, a new species of large barb (Teleostei: Cyprinidae) from the Western Ghats of India, pp. 316-328 in Zootaxa 4184 (2) on pages 317-324, DOI: 10.11646/zootaxa.4184.2.4, http://zenodo.org/record/164764