Indoreonectes evezardi (Day, 1872)

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 evezardi (Day, 1872)

Figs 3 , 4 , 5 , 6

Nemacheilus evezardi Day, 1872: p. 182

Oreonectes (Indoreonectes) evezardi (Day, 1872): Rita, Bănărescu and Nalbant (1978, 186)

Material examined.

BNHS FWF 1068-1070, 3 ex., 33.1-43.81 mm SL, India: Maharashtra, Mutha River , Krishna river system, Pune (18°23.28'N; 73°38.52'E, ca 580 m a.s.l.), coll. M. Pise, P. Gorule and P. Kumkar 8 Oct. 2017 . BNHS FWF 299-300, 2 ex., 40.5-44.6 mm SL, Mutha River at Warje (18°28.32'N; 73°48.48'E), Pune, Maharashtra, India, coll. N. Dahanukar and M. Paingankar, 10 Jul. 2008 ; WILD-17-PIS-350-358, 9 ex., 35.0-43.0 mm SL, Mutha River at Warje (18°28.32'N; 73°48.48'E), Pune, Maharashtra, India, coll. N. Dahanukar and M. Paingankar, 10 Jul. 2008 ; WILD-17-PIS-359, 1 ex., 33.5 mm SL, Mutha River at Panshet (18°26.16'N; 73°38.1'E), Pune, Maharashtra, India, coll. P. Kumkar, 8 Oct. 2017 .

Diagnosis.

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

Description.

General morphology is shown in Figure 3 ; 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 deeper than long. Lateral line present (14) or absent (1), when present then incomplete, short, ending above middle of adpressed pectoral fin. Scales minute.

Head small, slightly longer than a quarter of SL. Snout round, its length more than one-third of head length. Eye dorsolaterally positioned, closer to tip of snout than to posterior margin of opercle, its diameter 10-16% HL. Mouth semi-circular, with thick fleshy lips, lower lip interrupted medially by a deep groove (Fig. 4A ). 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 slightly posterior to pelvic-fin origin; slightly closer to caudal-fin base than tip of snout, its posterior edge rounded, with 4 (15) simple and 7 (15) branched rays. Pectoral fin slightly shorter than head length; with 1 (15) simple and 9 (3) or 10 (12) branched rays. Pelvic fin with 1 (15) simple and 7 (15) branched rays. Anal fin with 3 (15) simple and 5 (15) branched rays. Caudal fin rounded, with 9+9 (15) principal caudal-fin rays. Dorsal procurrent rays 11(8) or 13(7) and ventral procurrent rays 6(10) or 7(5).

Total vertebrae 35 (Fig. 5A ) with 17 (2) abdominal and 18 (2) caudal vertebrae. Dorsal-fin insertion in both cleared and stained specimens is between neural spines of 12th and 13th abdominal vertebrae. Fifth ceratobranchial (Fig. 6A ) with single row of 15 to 16 small curved teeth with pointed tips; anterior teeth longer than posterior ones.

Colouration.

In life (Fig. 3A ), background colour pale yellow, slightly darker on dorsal profile than lateral profile; with brownish-black irregular bars on lateral and dorsal side of body, lateral and dorsal bars separated from each other; lateral bars narrower than inter-bar spaces; lateral complete bars 13 (3), 14 (6), 15 (4) or 16 (2); lateral incomplete bars 4 (6), 5 (6), 6 (2) or 7 (1). Head dorsally covered with dark brown spots; cheek spots below eye absent. Caudal peduncle bar split into two conspicuous spots. Dorsal fin anterior spot dark brown to black in colour; dorsal-fin membrane hyaline with three rows of black spots on rays. Pectoral, pelvic 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. 3B-D ), colouration similar to that in life, but less conspicuous.

Habitat and distribution.

Indoreonectes evezardi was collected from fast-flowing clear streams with substrate consisting of rock, pebbles and sand. Co-occurring fish species include Paracanthocobitis mooreh , Schistura denisoni , Rasbora dandia and Devario malabaricus . Indoreonectes evezardi sensu stricto is currently known only from its type locality in Pune (see Keskar et al. 2018) from Mutha River a tributary of the east flowing Krishna river system, Maharashtra, India (Fig. 1 ).

Remarks.

The types of I. evezardi are not traceable and are suspected to be lost (see for details, Prasad et al. 2020). Specimens we examined, which include the specimens studied by Prasad et al. (2020) from the type locality in Pune, closely resemble the specimens in the original description of the species as pointed out by Prasad et al. (2020). However, it should be mentioned that in the original description Day (1872) mentions that the lateral line is absent in I. evezardi . However, this is a relatively rare character state and out of total 15 individuals we examined, the lateral line is absent in only one specimen. In all other specimens the lateral line is present, but incomplete and does not extend beyond the middle of the adpressed pectoral fin.

Figures

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

Figure 3. Indoreonectes evezardi (BNHS FWF 1070, 33.5 mm SL), topotype, collected from Kuran, Mutha River, Pune, in life (A) and preserved (B - D).

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.