Barilius profundus, a new cyprinid fish (Teleostei: Cyprinidae) from the Koladyne basin, India
M. Dishma1 & W. Vishwanath2
1,2 Department of Life Sciences, Manipur University, Canchipur, Manipur 795003, India
Email: 1 email@example.com, 2 firstname.lastname@example.org (corresponding author)
Fishes of the genus Barilius Hamilton are characterised by a compressed body, blue-black bars or spots on the body and dorsal fin inserted behind the middle of the body (Hamilton 1822). The members of this genus are inhabitants of medium to fast flowing torrential mountain streams of China, western Asia, South and mainland South-east Asia. Thirteen species of the genus are hitherto known from the Eastern Himalaya region (Vishwanath et al. 2010). They are: B. ngawa Vishwanath & Manojkumar, B. dogarsinghi Hora, B. chatricensis Selim & Vishwanath, B. lairokensis Arunkumar & Tombi from the Chindwin drainage; B. barila (Hamilton), B. bendelisis (Hamilton), B. tileo (Hamilton), B. shacra (Hamilton), B. vagra (Hamilton), B. barna (Hamilton), B. dimorphicus Tilak & Husain, B. radiolatus Gunther, and B. bonarensis Chaudhuri from the Ganga-Brahmaputra drainage. The Koladyne River in Mizoram, northeastern India, is a drainage connected neither with the Ganga-Brahmaputra nor the Chindwin drainages. Its icthyofauna is poorly explored. Collections from the river (also known as Kaladan or Chhimtuipui) include an undescribed species of Barilius which is herein described as a new species.
Materials and Methods
Measurements were made point to point on the left side of specimens wherever possible with dial calipers to the nearest 0.1mm. The colour in fresh specimens was noted before fixation and preservation in 10% formalin. Counts and measurements follow Kottelat (1990) and lateral line scale count, Kottelat (2001). Head length (HL) and anatomical measurements are expressed as proportions of standard length (SL) and subunits of head as proportions of head length (HL). Osteological structures were observed in a cleared and alizarin-stained specimen following Hollister (1934). Vertebral counts follow Weitzman (1962). Fin rays were counted under a stereo-zoom light microscope. Type specimens are deposited in the Manipur University Museum of Fishes (MUMF).
Barilius profundus sp. nov.
Holotype: 24.xii.2009, 22023ÕN & 92057ÕE, 71.1mm SL; Koladyne River at Kolchaw, Lawntlai District, Mizoram, India, coll. Nebeshwar and party, MUMF 27001.
Paratypes: 4 exs., 55.2–67.7 mm SL, data as for holotype, MUMF 27002-27005; 8 exs., 30.xi.2008, 50.9–69.9 mm SL; Koladyne River at Kolchaw, Lawntlai District, Mizoram, India, coll. Nebeshwar & party, MUMF 27021-27028. One paratype (MUMF 27005, 54.5mm SL) dissected for osteology.
A species of Barilius with the following combination of characters: great body depth at dorsal-fin origin (32.0–37.3 % SL); 17–18 pre-dorsal scales; 7–10 dark blue bars against faintly brown to yellowish-cream background of body, width of bar narrower than interspace width; lateral line complete with 30–32 + 2–3 scales; eye diameter (38.3–42.9 % HL), predorsal length (58.9–64.0 % SL); dorsal-fin length (21.6–25.7 % SL); ½7/1/2½ lateral transverse scales; 12 circumpeduncular scales; and 35 vertebrae.
Morphometric data are shown in Table 1 and Appendix 1. Body compressed, abdomen rounded. Dorsal profile in front of dorsal-fin origin relatively straight, gently sloping downward towards base of caudal peduncle. Ventral profile slightly curved till pectoral-fin origin, then straight up to anal-fin origin, thereafter sloping dorsally to end of caudal peduncle. Muscular pads present at base of pectoral and pelvic fins.
Head moderately compressed; shorter than wide. Snout blunt, profile dorsally curved and rounded when viewed laterally, length shorter than interorbital distance. Eyes large, slightly bulging (convex), visible both from dorsal and ventral sides of head, situated in anterior half of head, diameter smaller than interorbital distance. Interorbital space slightly arched. Mouth terminal, obliquely directed upwards. Gape of mouth reaches anterior margin of orbit. Tubercles on snout and lower jaw poorly developed.
Barbels two pairs, short. One pair each of rostral and maxillary. Lips thin. Nostrils almost at level of upper margin of eye, distinctly nearer to anterior margin of eye than tip of snout. Jaws equal in length. Lower jaw without symphysial knob.
Dorsal fin inserted posterior to pelvic-fin origin with ii, 7½ rays and closer to caudal-fin base than tip of snout; longer than pelvic and anal fin; tip of last branched ray extending to middle of anal fin base. Pectoral fin with i,11 rays, shorter than head length; their tips pointed or nearly so; not reaching pelvic-fin origin. Pelvic fin with i, 8 rays, its origin much nearer to anal-fin origin than pectoral-fin origin, shorter than head length and pectoral fin; pelvic fin not reaching anal opening. Anal-fin origin just below base of last dorsal fin ray, with ii, 10½ rays; not reaching caudal peduncle when adpressed; fin margin concave. Anal fin shorter than head length. Anal opening located immediately anterior to anal-fin origin. Caudal fin deeply forked with i, 9+8, i principal rays, both upper and lower lobes equal in length.
Scales moderate. Circumpeduncular scales 12, lateral transverse scale ½7/1/2½. Lateral line complete with 30–32 + 2–3 scales. Vertebrae 18+17= 35 including complex vertebra.
Colour: In a fresh specimen, dorsal and dorsolateral surfaces of head and body faintly brown, ventral portion anterior to pelvic-fin origin silver coloured. Belly creamy to golden yellowish and with 7–10 dark blue bars on the sides; first anterior-most dark blue bar extends beyond lateral line, sometimes first two or three anterior-most bars touch lateral line. Dorsal fin hyaline with a row of elongated black marks. Pectoral, pelvic and anal fins golden yellow with hyaline distal margins. Caudal fin edged with black, faintly yellowish-green at the base.
In 10% formalin, body creamy, slightly dark dorsally. Dorsal fin hyaline with a row of elongated black marks. Caudal fin hyaline, edged with black. Pectoral, anal and ventral fins hyaline without dark bands.
The species name ŌprofundusÕ (Latin, meaning deep) is in reference to its great body depth, an adjective.
Presently known only from the Koladyne River at Mizoram (Fig. 1, Image 2).
Barilius profundus sp. nov. is close to its nearest congeners, B. dogarsinghi and B. barna in having a dorsal fin with 7½ branched rays and a pelvic fin with eight branched rays. However, the new species differs from B. dogarsinghi in having greater body depth at dorsal-fin origin (32.0–37.3% SL vs. 24.8–30.0), eye diameter (38.3–42.9 % HL vs. 29.2–33), and branched anal-fin rays (10½ vs. 9½); lesser pre-dorsal scales (17–18 vs. 20), lateral line scales (30–32 + 2–3 vs. 37–40 + 2). It differs from B. barna in having greater body depth at dorsal-fin origin (32.0–37.3% SL vs. 29.0–30.8); presence (vs. absence) of barbels; longer predorsal distance (58.9–64.0% SL vs. 53.9–54.9), anal-fin distance (16.6–20.4% SL vs. 13.3–15.1); shorter caudal peduncle (11.4–15.6% SL vs. 16.1–16.9); more predorsal scales (17–18 vs. 15–16); lesser lateral line scales (30–32 + 2–3 vs. 36–39 + 2–3), and branched pectoral-fin rays (11 vs. 12).
Barilius profundus sp. nov. differs from B. barila, B. tileo, B. shacra and B. vagra in having greater body depth at dorsal-fin origin 32.0–37.3 % SL (vs. 23.4–24.0 in B. barila, 29.9 in B. tileo, 22.2–23.2 in B. shacra and 25.2–26.7 in B. vagra), 17–18 predorsal scales (vs. 22 in B. barlia, 28 in B. tileo, 22–25 in B. shacra and 21–22 in B. vagra) and 30–32 + 2–3 lateral line scales (vs. 40–42 + 2–3 in B. barila, 59+4 in B. tileo, 59–70 in B. shacra and 40–42 + 3 in B. vagra). Barilius profundus sp. nov. further differs from B. bendelisis in having greater body depth at dorsal-fin origin (32.0–37.3% SL vs. 22.1–26.1), 30–32 + 2–3 lateral line scales (vs. 39–42 + 2–4), scales without dark spot (vs. with dark spot); from B. radiolatus in having greater body depth at dorsal-fin origin (32.0–37.3% SL vs. 22.2), 30–32 + 2–3 lateral line scales (vs. 58), ventral fin not reaching vent (vs. reaching vent); from B. bonarensis in having greater body depth at dorsal-fin origin (32.0–37.3% SL vs. 21.7–22.2), 30–32+2–3 lateral line scales (vs. 47); from B. dimorphicus in having greater body depth at dorsal-fin origin (32.0–37.3% SL vs. 24.9–28.8), 30–32 + 2–3 lateral line scales (vs. 60–66), 17–18 predorsal scales (vs. 25–27). The new species differs from B. ngawa, B. chatricensis and B. lairokensis in having greater body depth at dorsal-fin origin (32.0–37.3 % SL vs. 24.8–28.3 in B. ngawa, 23.2 in B. chatricensis, 25.5 in B. lairokensis), 17-18 predorsal scales (vs. 21–22 in B. ngawa, 15 in B. chatricensis, 21 in B. lairokensis), 30–32 + 2–3 lateral line scales (40–41 + 2–3 in B. ngawa, 36+2 in B. chatricensis, 41+3 in B. lairokensis).
In case of Barilius radiolatus, B. bonarensis, B. dimorphicus and B. shacra, the specimens are not available for examination. Thus, the lateral line scale counts used for comparison are from the published data, which might include the pored scales behind the hypural plate which are normally 2–3. However, the differences in the counts are great and we can confirm these to be different.
Kar & Sen (2007) listed three species of Barilius viz., B. barna, B. vagra and B. shacra from the Koladyne River basin but they neither gave descriptions of the species nor mentioned where the collections were eventually deposited. The three species are not represented from the basin in our collections. However, we compared B. profundus sp. nov. with B. barna, B vagra from the Dikrong and Barak rivers (both Brahmaputra drainage) respectively and with B. shacra using the published data. As noted above, the three species are readily distinguishable from the new species.
Barilius barila: MUMF 5049, 5051, 83.2–89.5 mm SL, Khuga River, Churchandpur, Manipur, India.
Barilius barna: MUMF 27061–27064, 73.0–83.1 mm SL, Dikrong River, Arunachal Pradesh, India.
Barilius bendelisis: MUMF 27067–27068, 100.3–105.8 mm SL, Iyei River, Noney, Manipur, India; MUMF 27069–27072, 72.4–105 mm SL, western side of Maram Khulen & Laironching, Manipur, India.
Barilius chatricensis: MUMF 503/1 (holotype), 86.4mm SL, Chatrickong River, Ukhrul District, Manipur, India. 150 km from Imphal. Additional data from Selim & Vishwanath (2002).
Barilius dogarsinghi: MUMF 207–210, 52.9–72.2 mm SL, Chakpi stream, Manipur, India.
Barilius ngawa: MUMF 149 (holotype), 96.5mm SL, Sherou River (tributary of Manipur river), 83km south of Imphal, Manipur, India; MUMF 27056–27058, 80.0–82.9 mm SL, Singda, Manipur, India.
Barilius lairokensis: MUMF 27075, 105.0 mm SL, Moreh bazar, Moreh, Chandel District, Manipur, India.
Barilius vagra: MUMF 4091–4093, 88.0–107.3 mm SL, Barak River, Vanchengphai, Tamenglong District, Manipur, India.
Barilius tileo: MUMF 27076, 128.1mm SL, Umtrao River, Byrnihat, Norbong, Ribhoi District, Assam, India.
Barilius dimorphicus: Data from Tilak & Husain (1990).
Barilius bonarensis: Data from Chaudhuri (1912).
Barilius shacra: Data from Talwar & Jhingran (1991).
Barilius radiolatus: Data from Gunther (1868).
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