Indoreonectes neeleshi, Kumkar & Pise & Gorule & Verma & Kalous, 2021

Kumkar, Pradeep, Pise, Manoj, Gorule, Pankaj A., Verma, Chandani R. & Kalous, Lukas, 2021, Two new species of the hillstream loach genus Indoreonectes from the northern Western Ghats of India (Teleostei: Nemacheilidae), Vertebrate Zoology 71, pp. 517-533 : 517

Indoreonectes neeleshi sp. nov.

Figs 4 , 5 , 6 , 7 Common name: Neelesh’s hill stream loach

Holotype.

BNHS FWF 1071, 38.54 mm SL, India: Maharashtra, Mula River, Godavari river system, Harishchandragad (19°23.64′N; 73°46.74′E, ca 1180 m a.s.l.), coll. M. Pise and P. Kumkar 30 Mar. 2018.

Paratypes.

BNHS FWF 1072-1080, 9 ex., 28.2-36.3 mm SL, same data as holotype. Paratypes BNHS FWF 1074 (36.26 mm SL), and BNHS FWF 1075 (32.43 mm SL) used for clearing and staining.

Diagnosis.

Indoreonectes neeleshi can be distinguished from all congeners by having the lateral bars wider than inter-bar spaces (vs. narrower in I. evezardi , I. keralensis I. telanganaensis , and I. rajeevi ). Further, Indoreonectes neeleshi can be distinguished from I. keralensis by having long nasal barbel reaching middle of eye (vs. short nasal barbel barely reaching anterior margin of eye); inner rostral barbel reaching middle of nostril (vs. reaching further posteriorly to anterior margin of eye); presence of dorsal hump behind nape (vs. absence); presence of a dark brown to black spot on base of first dorsal-fin ray and distinct spots on the dorsal side of head (vs. absence); caudal peduncle as deep as long (vs. longer than deep); spots on cheek below eye absent (vs. present). Indoreonectes neeleshi can be distinguished from I. evezardi by having caudal peduncle as deep as long (vs. deeper than long); caudal peduncle bar not divided (vs. divided into two spots). Indoreonectes neeleshi can be distinguished from I. telanganaensis by having inner rostral barbel reaching middle of nostril (vs. reaching further posteriorly to anterior margin of eye); spots on cheek below eye absent (vs. present). Indoreonectes neeleshi can be distinguished from I. rajeevi by having inner rostral barbel reaching middle of nostril (vs. reaching further posteriorly to anterior margin of eye); maxillary barbel not reaching posterior border of operculum (vs. reaching to posterior border of operculum); absence of conspicuous black marking on lower lip (vs. presence); presence of dorsal hump behind nape (vs. absence); dorsal-fin insertion between neural spines of 13th and 14th abdominal vertebrae (vs. between 12th and 13th abdominal vertebrae); caudal peduncle as deep as long (vs. slightly longer than deep); total vertebrae 35 (vs. 36).

Description.

General morphology is shown in Figure 7 ; morphometric data are provided in Table 1 .

Body sub-cylindrical, elongate; head and anterior part of body almost cylindrical; body laterally compressed posteriorly; predorsal outline convex, gradually rising up to dorsal-fin origin, a distinct hump behind nape; postdorsal outline straight up to base of caudal fin; ventral profile almost straight. Caudal peduncle as deep as long. Lateral line present, incomplete, short, ending above middle of adpressed pectoral fin. Scales minute.

Head small, less than a quarter of SL. Snout round, its length more than one-third of head length. Eye dorso-laterally positioned, closer to tip of snout than to posterior margin of operculum, its diameter about 15% HL. Mouth semi-circular, with thick fleshy lips, lower lip interrupted medially by a deep groove (Fig. 4B ). Barbels four pairs. Two pairs of rostral barbels, inner rostral barbel extending to middle of nostril, outer rostral barbel reaching anterior margin of eye; Maxillary barbel longest, originating at vertical from nostril, reaching midway between eye and posterior border of operculum. Nasal barbel well developed, reaching middle of eye.

Dorsal-fin origin at vertical from ventral-fin origin; slightly closer to caudal-fin base than tip of snout, its posterior margin rounded, with 4 (10) simple and 7 (10) branched rays. Pectoral fin slightly shorter than head length; with 1 (10) simple and 9 (10) branched rays. Pelvic fin with 1 (10) simple and 7 (10) branched rays. Anal fin with 3 (10) simple and 5 (9) or 6 (1) branched rays. Caudal fin rounded, 8+9 (1) or 9+9 (9) principal caudal-fin rays. Dorsal procurrent rays 10(8) or 11(2) and ventral procurrent rays 6(6) or 7(4).

Total vertebrae 35 (Fig. 5B ) with 17 (2) abdominal and 18 (2) caudal vertebrae, but vertebral column malformed in both cleared and stained specimens. Dorsal-fin insertion between 13th and 14th abdominal vertebrae. Fifth ceratobranchial (Fig. 6B ) with single row of 12 to 17 small curved teeth with pointed tips; anterior teeth longer than posterior.

Colouration.

In life (Fig. 7A ), background colour yellow ochre slightly darker on dorsal profile of anterior side; with grey irregular bars on lateral and dorsal side of body, lateral and dorsal bars separated from each other; lateral bars wider than inter-bar spaces; lateral complete bars 12 (4), 13 (2), 14 (3) or 16 (1); lateral incomplete bars 4 (2), 5 (5) or 6 (3). Head dorsally studded with dark brown spots; cheek spots below eye absent. Caudal peduncle bar continuous but sometimes faint in the middle. Dorsal fin anterior spot dark brown to black in colour; dorsal fin membrane hyaline with three rows of black spots on rays. Pectoral, ventral and anal fins hyaline, lacking spots; caudal fin with membrane hyaline, and three to four rows of dark-brown spots on rays. Ventral surface without any markings. In preservative (Fig. 7B-D ), colouration similar to that in life, but faded.

Etymology.

The species name honours Neelesh Dahanukar researcher from Indian Institute of Science Education and Research (IISER), Pune, India, for his remarkable contributions to the understanding of the systematics and evolution of Indian freshwater fishes.

Habitat and Distribution.

Indoreonectes neeleshi was found in a fast-flowing clear stream with a rocky substrate. Co-occurring fish species include Parapsilorhynchus sp. and the exotic Gambusia affinis . Currently, Indoreonectes neeleshi is known only from its type locality in the Mula tributary of East flowing Godavari River at Harishchandragad, Maharashtra, India (Fig. 1 ).

Figures

Figure 1. Type localities of species of the genus Indoreonectes in southern Peninsular India.

Figure 4. Mouth of Indoreonectes species, in ventral view. (A) Indoreonectes evezardi (BNHS FWF 1070, 33.5 mm SL), (B) I. neeleshi holotype (BNHS FWF 1071, 38.5 mm SL), (C) I. rajeevi holotype (BNHS FWF 1081, 45.8 mm SL) and (D) I. keralensis (KUFOS. 2017. 11.217, 36.1 mm SL). Scale bar 2 mm. Red arrows in C points to conspicuous black markings on lower lip in I. rajeevi.

Figure 5. Cleared and stained specimens of Indoreonectes showing vertebral column and insertion of dorsal fin, in lateral view. (A) Indoreonectes evezardi (BNHS FWF 1068, 43.8 mm SL), (B) I. neeleshi (BNHS FWF 1074, 36.2 mm SL), (C) I. rajeevi (BNHS FWF 1090, 35.1 mm SL) and (D) I. keralensis (KUFOS. 2017.11.217, 36.1 mm SL). Scale bar 5 mm. Note that vertebral column of I. neeleshi is malformed in caudal region.

Figure 6. Cleared and stained fifth ceratobranchials showing dentition pattern, in dorsal view. (A) Indoreonectes evezardi (BNHS FWF 1068, 43.8 mm SL), (B) I. neeleshi (BNHS FWF 1074, 36.2 mm SL), (C) I. rajeevi (BNHS FWF 1090, 35.1 mm SL) and (D) I. keralensis (KUFOS. 2017. 11.217, 36.1 mm SL). Scale bar 0.5 mm.

Figure 7. Indoreonectes neeleshi holotype (BNHS FWF 1071, 38.54 mm SL) (A) in life, in lateral view; preserved in lateral (B), dorsal (C) and ventral (D) views.