Research Article |
Corresponding author: Pradeep Kumkar ( kumkarpradeep@gmail.com ) Academic editor: Ralf Britz
© 2021 Pradeep Kumkar, Manoj Pise, Pankaj A. Gorule, Chandani R. Verma, Lukáš Kalous.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Kumkar P, Pise M, Gorule PA, Verma CR, Kalous L (2021) Two new species of the hillstream loach genus Indoreonectes from the northern Western Ghats of India (Teleostei: Nemacheilidae). Vertebrate Zoology 71: 517-533. https://doi.org/10.3897/vz.71.e62814
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The hill stream loach genus Indoreonectes is endemic to peninsular India south of the Satpura hill ranges and is represented by three species I. evezardi, I. keralensis and I. telanganaensis. Indoreonectes evezardi has been suggested as a species complex based on recent genetic studies; however, due to lack of type material the species delimitation has been difficult. Here we redescribe I. evezardi collected from its type locality and describe two new species from the northern Western Ghats of India. Indoreonectes neeleshi, described from Mula River tributary of Godavari river system, can be diagnosed from all its congeners based on a combination of characters: inner rostral barbel reaching middle of nostril; maxillary barbel reaching midway between eye and posterior border of operculum; dorsal hump behind nape; bars on lateral side of the body wider than inter-bar space; total vertebrae 35 and dorsal fin insertion between 13th and 14th abdominal vertebrae. Indoreonectes rajeevi, described from Hiranyakeshi River of the Krishna river system, differs from all its congeners based on a combination of characters: inner rostral barbel reaching anterior margin of eye; maxillary barbel reaching posterior border of operculum; conspicuous black markings on lower lip, dorsal hump absent; total vertebrae 36 and dorsal fin insertion between 12th and 13th abdominal vertebrae. Further, I. neeleshi differs from its congeners by the raw genetic distance of 6.8–14.4% for the cox1 gene and 5.7–16.2% for the cytb gene, while I. rajeevi differs from its congeners by the raw genetic distance of 10.9–14.0% for the cox1 gene and 11.8–15.8% for the cytb gene.
Biodiversity hotspot, Godavari river system, Krishna river system, Maharashtra
The genus Indoreonectes Rita, Bănărescu and Nalbant of hill stream loaches (Cypriniformes: Nemacheilidae) was initially proposed as a subgenus of Oreonectes Günther, while describing O. (Indoreonectes) keralensis Rita and Nalbant (
Indoreonectes evezardi has been considered to be a widely distributed species in peninsular India north of the Palghat Gap, occurring in the east-flowing Krishna, Godavari and Cauvery river systems in addition to several west-flowing rivers in Goa, Maharashtra, and Gujarat states, while I. keralensis is restricted to river systems south of the Palghat gap, particularly the Periyar, Pampa, Muvattupuzha, and Meenachil rivers of Western Ghats of Kerala (
Based on extensive genetic sampling from the northern Western Ghats,
In the current study we redescribe Indoreonectes evezardi from its type locality using fresh collections and specimens studied by
Individuals of the new species of Indoreonectes were collected from two different localities, one in the upper reaches of Godavari river system in Maharashtra at Harishchandragad (19°23.64′N; 73°46.74′E, ca 1180 m a.s.l.) (ten individuals) and another from Krishna river system in Maharashtra at Amboli (15°58.02′N; 74°0.66′E, ca 692 m a.s.l.) (twelve individuals) (Fig.
Measurements were taken for each specimen to the nearest 0.1 mm using digital callipers (Mitutoyo, Japan). Morphometric methods follow
Two paratypes of I. neeleshi (BNHS FWF 1074–75), three paratypes of I. rajeevi (BNHS FWF 1090–92), two specimens of topotypic I. evezardi (BNHS FWF 1068–1069) and one specimen of I. keralensis (KUFOS.2017.11.217) were cleared and stained to study skeletal morphology following the procedure described by
Gill tissues were extracted from a paratype of each species preserved in absolute alcohol (Indoreonectes neeleshi – BNHS FWF 1080 and I. rajeevi – BNHS FWF 1089). DNA was extracted using QIAamp DNA Mini Kit (Qiagen, Hilden, Germany) following the protocol given by the manufacturer. Mitochondrial cytochrome oxidase subunit I (cox1) gene was amplified using Polymerase Chain Reaction with primers FishF1 and FishR1 (
Gene sequences were aligned with MUSCLE (
Nemacheilus evezardi Day, 1872: p. 182
Oreonectes (Indoreonectes) evezardi (Day, 1872): Rita, Bănărescu and Nalbant (1978, 186)
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.
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).
General morphology is shown in Figure
Morphometric data of Indoreonectes evezardi topotypes (BNHS FWF 299–300, 1068–1070, BNHS FWF, WILD-17-PIS-350–359), I. neeleshi holotype (BNHS FWF 1071), paratypes (BNHS FWF 1072–1080) and I. rajeevi holotype (BNHS FWF 1081) and paratypes (BNHS FWF 1082-1092). Mean, standard deviation (sd) and range of new species include holotype.
Characters | I. evezardi (n = 15) | I. neeleshi (n = 10) | I. rajeevi (n = 12) | ||||||
Mean (sd) | Range | Holotype | Mean (sd) | Range | Holotype | Mean (sd) | Range | ||
Total length (mm) | 45.2 (4.4) | 40.5–53.3 | 47.9 | 39.6 (4.1) | 34–47.9 | 55.9 | 41.2 (5.7) | 33.2–55.9 | |
Standard length (SL, mm) | 37.7 (3.8) | 33.5–44.6 | 38.5 | 32.1 (3.2) | 28.2–38.5 | 45.8 | 33.9 (4.8) | 26.4–45.8 | |
Head length (HL, mm) | 8.9 (0.8) | 8.0–10.8 | 8.3 | 7.1 (0.8) | 5.9–8.3 | 8.8 | 6.8 (1.0) | 5.3–8.8 | |
%SL | |||||||||
Head length | 23.7 (0.8) | 22.3–25.2 | 21.4 | 22 (0.9) | 20.8–24.1 | 19.3 | 20 (1.1) | 17.7–21.4 | |
Predorsal length | 55.4 (1.5) | 52.0–57.2 | 55.3 | 56.5 (1.2) | 54.6–58.7 | 52.5 | 53.9 (1.2) | 52.2–56.1 | |
Dorsal-fin origin to caudal-fin base | 46.4 (1.4) | 43.8–48.8 | 48.6 | 46.3 (1.3) | 45.2–48.7 | 48.7 | 47.8 (1.0) | 45.8–49.0 | |
Prepectoral length | 24.1 (1.1) | 21.9–25.3 | 23.8 | 22.9 (0.9) | 21.3–23.9 | 20.3 | 21.7 (0.9) | 20.3–22.8 | |
Prepelvic length | 54.1 (1.7) | 50.8–56.0 | 50.7 | 52.6 (1.7) | 50.7–55.7 | 50.9 | 49.9 (2.4) | 42.7–51.4 | |
Preanus length | 75.2 (1.2) | 72.3–77.1 | 72.0 | 72.6 (1.9) | 70.1–76.3 | 71.4 | 70.1 (2.1) | 66.9–73.3 | |
Preanal-fin length | 80.9 (1.4) | 78.1–82.8 | 78.1 | 79.1 (1.6) | 76.3–81.4 | 77.3 | 76.5 (1.7) | 73.6–78.9 | |
Body depth (at dorsal-fin origin) | 17.8 (1.7) | 15.4–21.7 | 14.9 | 14.4 (1.8) | 11.2–16.1 | 14.7 | 14.8 (1.2) | 12.3–16.1 | |
Body depth (at anus) | 15.9 (1.3) | 14.5–19.0 | 14.2 | 13.7 (1.5) | 10.3–15.2 | 13.7 | 12.9 (0.9) | 10.9–13.8 | |
Body width (at dorsal-fin origin) | 12.6 (1.5) | 10.3–14.9 | 13.9 | 12.1 (1.6) | 8.6–13.9 | 12.7 | 11.2 (1.3) | 8.5–13.5 | |
Body width (at anus) | 9.6 (1.4) | 7.1–11.6 | 10.4 | 9.3 (1.4) | 6.4–10.6 | 10.3 | 8.9 (1.3) | 6.0–10.9 | |
Height of dorsal fin | 17.7 (1.2) | 16.1–19.9 | 18.9 | 18.5 (1.3) | 15.8–20.4 | 17.1 | 18.4 (1.3) | 16.6–20.7 | |
Length of dorsal-fin base | 10.7 (0.8) | 9.5–12.2 | 12.7 | 10.6 (1.3) | 8.1–12.7 | 11.8 | 11.6 (1.5) | 9.0–13.7 | |
Length of pectoral fin | 18.2 (1.9) | 12.1–20.0 | 20.2 | 19.7 (0.6) | 18.6–20.4 | 17.5 | 17.8 (0.9) | 16.9–19.9 | |
Length of pelvic fin | 16.5 (1.2) | 14.4–18.1 | 17.7 | 17.4 (1.0) | 15.8–19.0 | 16.5 | 16.8 (0.9) | 15.5–18.2 | |
Length of anal fin | 14.8 (0.7) | 13.7–15.8 | 15.7 | 14.7 (1.1) | 13.0–15.9 | 15.6 | 15.6 (1.3) | 13.0–17.6 | |
Length of anal-fin base | 6.9 (0.6) | 5.9–7.9 | 6.9 | 6.4 (0.6) | 5.1–7.0 | 7.8 | 7.4 (0.8) | 5.8–8.3 | |
Length of caudal fin | 20.4 (1.1) | 18.5–22.4 | 23.1 | 22.5 (0.9) | 20.9–23.3 | 21.4 | 20.6 (0.9) | 18.7–21.8 | |
Depth of caudal peduncle | 14.8 (1.5) | 12.5–16.9 | 14.7 | 13.9 (2.2) | 9.7–16.4 | 13.1 | 13.6 (0.8) | 12.1–14.6 | |
Length of caudal peduncle | 11.6 (1.4) | 9.8–15.5 | 14.6 | 14.1 (1.7) | 12.0–17.7 | 13.8 | 15.3 (1.6) | 12.7–17.5 | |
% HL | |||||||||
Head depth | 55.1 (4.7) | 45.4–60.1 | 64.0 | 60.6 (2.9) | 55.6–64.0 | 62.4 | 59.6 (5.6) | 47.0–66.6 | |
Head width | 69.1 (4.3) | 59.3–74.5 | 78.9 | 74.5 (4.3) | 66.5–78.9 | 75.9 | 72.8 (6) | 60.5–79.1 | |
Snout length | 41.3 (2.5) | 36.1–45.1 | 46.2 | 43.1 (3.4) | 36.5–46.3 | 46.8 | 45 (4.2) | 38.5–51.9 | |
Eye diameter | 12.2 (1.7) | 9.8–15.9 | 15.7 | 15.6 (1.0) | 14.2–17.9 | 16.7 | 17.5 (1.9) | 14.1–20.7 | |
Interorbital width | 37.3 (2.5) | 32.9–41.4 | 45.3 | 40.1 (3.8) | 33.3–45.3 | 39.6 | 38.2 (5.2) | 28.1–45.3 | |
Width of mouth | 29.6 (4.4) | 24.3–37.5 | 37.4 | 32.9 (3.1) | 29.5–37.8 | 42.6 | 34.9 (4) | 28.0–42.6 |
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.
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.
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.
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.
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.
In life (Fig.
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
The types of I. evezardi are not traceable and are suspected to be lost (see for details,
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.
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.
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).
General morphology is shown in Figure
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.
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.
In life (Fig.
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.
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.
BNHS FWF 1081, 45.76 mm SL, India: Maharashtra, Hiranyakeshi River, Krishna river system, Amboli (15°58.02’N; 74°0.66’E, ca 692 m a.s.l.), coll. P. Gorule and A. Gorule 23 Oct. 2017.
BNHS FWF 1082–1092, 11 ex., 26.4–36.3 mm SL, same data as holotype. Paratypes BNHS FWF 1090 (35.1 mm SL), 1091 (33.0 mm SL) and 1092 (35.2 mm SL) used for clearing and staining.
Indoreonectes rajeevi can be distinguished from all congeners by having maxillary barbel reaching the posterior border of operculum (vs. not reaching); presence of conspicuous black marking on the lower lip of mouth (vs. absence).
Indoreonectes rajeevi is further distinguished from I. keralensis by having long nasal barbel reaching middle of eye (vs. short nasal barbel barely reaching anterior margin of eye); dorsal-fin origin vertical from pelvic-fin base (vs. posterior to vertical at pelvic-fin base); 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 on base of first dorsal-fin ray and distinct spots on dorsal side of head (vs. absence); spots on cheek below eye absent (vs. present); total vertebrae 36 (vs. 35).
Indoreonectes rajeevi is distinguished from I. evezardi by having inner rostral barbel reaching anterior margin of eye (vs. reaching middle of nostril); absence of dorsal hump behind nape (vs. presence); dorsal fin origin at vertical from pelvic-fin base (vs. posterior to vertical at pelvic-fin base); caudal peduncle slightly longer than deep (vs. deeper than long); caudal peduncle bar not divided into two spots (vs. divided); total vertebrae 36 (vs. 35).
Indoreonectes rajeevi distinguished from I. telanganaensis by lacking spots on cheek below eye (vs. spots present); absence of dorsal hump behind nape (vs. presence); caudal peduncle slightly longer than deep (vs. as long as deep).
Indoreonectes rajeevi distinguished from I. neeleshi by having inner rostral barbel reaching anterior margin of eye (vs. reaching middle of nostril); absence of dorsal hump behind nape (vs. presence); dorsal-fin insertion between neural spines of 12th and 13th abdominal vertebrae (vs. between 13th and 14th); caudal peduncle slightly longer than deep (vs. as long as deep); lateral bars narrower than inter-bar spaces (vs. wider); total vertebrae 36 (vs. 35).
General morphology is shown in Figure
Body sub-cylindrical, elongate; head and anterior part of body almost cylindrical; body laterally compressed posteriorly; pre-dorsal outline slightly convex, gradually rising up to dorsal-fin origin, no hump behind nape; post dorsal outline straight up to base of caudal fin; ventral profile almost straight. Caudal peduncle as deep as long or slightly longer. Lateral line present, incomplete, short, ending above middle of adpressed pectoral fin. Scales minute.
Head small, about one fifth 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 operculum, its diameter about 14–20% HL. Mouth semi-circular, with thick fleshy lips, lower lip interrupted medially by a deep groove with conspicuous black markings on the either side of the groove (Fig.
Dorsal-fin origin at vertical from ventral-fin origin; slightly closer to caudal-fin base than tip of snout, its posterior margin rounded, with 3 (12) simple and 7 (12) branched rays. Pectoral fin slightly shorter than head length; with 1 (12) simple and 9 (12) branched rays. Pelvic fin with 1 (12) simple and 7 (12) branched rays. Anal fin with 3 (12) simple and 5 (12) branched rays. Caudal fin rounded, 8+9 (1) or 9+9 (11) principal rays. Dorsal procurrent rays 12(8) or 14(4) and ventral procurrent rays 6(10) or 7(2).
Total vertebrae 36 (Fig.
In life (Fig.
The species name honours Rajeev Raghavan from Kerala University of Fisheries and Ocean Studies (KUFOS), Kochi, India, for his remarkable contributions to the understanding of the Systematics and Evolution of Indian freshwater fishes.
Indoreonectes rajeevi was found in a slow-flowing clear stream with boulders, pebbles and mud as major substratum. Co-occurring fish species includes Parapsilorhynchus sp., Schistura sp., Balitora laticauda, Rasbora dandia and Garra mullya. Currently, Indoreonectes rajeevi is known only from its type locality in the Hiranyakeshi tributary of east flowing Krishna River at Amboli, Maharashtra, India (Fig.
The type species of the genus I. keralensis can be distinguished from all its congeners based on the following characters: nasal barbels short, barely reaching anterior border of eye (vs. long, reaching middle of eye or beyond); dorsal fin origin posterior to pelvic fin origin (vs. dorsal fin origin opposite to pelvic-fin origin); no spot on base of first dorsal-fin ray (vs. dark brown to black spot on base of first dorsal-fin ray); dorsal surface of head uniformly coloured with no distinct spots (vs. distinct spots on the dorsal side of head). In addition to these characters, I. keralensis differs from I. evezardi and I. rajeevi in the dorsal fin insertion between 13th and 14th abdominal vertebrae (vs. dorsal fin insertion between 12th and 13th abdominal vertebrae) and from I. rajeevi in having 35 total vertebrae (vs. 36).
Indoreonectes neeleshi can be distinguished from all its congeners based on characters such as lateral bars wider than inter-bar spaces (vs. narrower than inter bar spaces). In addition, I. neeleshi differs from I. evezardi in caudal peduncle bar not divided into two spots (vs. divided into two spots). Indoreonectes neeleshi further differs from I. evezardi and I. rajeevi in dorsal fin insertion between 13th and 14th abdominal vertebrae (vs. between 12th and 13th). Indoreonectes neeleshi also differs from I. telanganaensis and I. keralensis in the absence of spots on cheek below eye (vs. presence).
Indoreonectes rajeevi differs from all its congeners in having very long barbels, in particular nasal barbels long reaching posterior border of eye (vs. reaching between anterior border to mid of eye); maxillary barbels long reaching posterior border of operculum (vs. maxillary barbels short not reaching beyond midway between eye and posterior border of operculum); inner rostral barbel long reaching anterior margin of eye (vs. inner rostral barbel short reaching middle of nostril); conspicuous black marking on lower lip of mouth (vs. no marking on lower lip of mouth). In addition, I. rajeevi differs from I. evezardi, I. neeleshi and I. telanganaensis in the absence of a distinct hump behind nape (vs. present). It also further differs from I. evezardi, I. neeleshi and I. keralensis in having 36 (3) vertebrae (vs. 35 (2), 35 (2), 35 (1) respectively).
Based on the comparison provided above, the species of Indoreonectes can be identified using the following key modified from
1 | Nasal barbel short, barely reaching anterior border of eye; dorsal-fin origin posterior to pelvic-fin origin; no spot on base of first dorsal-fin ray; dorsal surface of head uniformly coloured, without distinct spots | Indoreonectes keralensis |
– | Nasal barbel reaching middle of eye or beyond; dorsal-fin origin opposite to pelvic-fin origin; dark brown to black spot on base of first dorsal-fin ray; distinct spots on dorsal side of head | 2 |
2 | Nasal barbel longer, reaching posterior border of eye; maxillary barbel long reaching posterior border of operculum; inner rostral barbel long reaching anterior margin of eye; conspicuous black marking on lower lip present; hump behind nape absent | Indoreonectes rajeevi |
– | Nasal barbel shorter, reaching middle of eye; maxillary barbel short, reaching midway between eye and posterior border of operculum; inner rostral barbel short, reaching middle of nostril; conspicuous black marking on lower lip absent; distinct dorsal hump behind nape | 3 |
3 | Lateral bars wider than inter-bar spaces | Indoreonectes neeleshi |
– | Lateral bars narrower than inter-bar spaces | 4 |
4 | Caudal peduncle as long as deep; caudal-peduncle bar not divided into two spots; spots on cheeks below eye | Indoreonectes telanganaensis |
– | Caudal peduncle deeper than long; caudal-peduncle bar expressed as two separate spots; no spots on cheeks below eye | Indoreonectes evezardi |
The best partitioning scheme and nucleotide substitution model for the partition scheme for concatenated sequences was identified as TN+F+I for combined partition of first two codon positions of cox1 and cytb genes (BIC = 10659.524), HKY+F for third codon position of cox1 (BIC = 2158.262) and TN+F+I for third codon position of cytb (BIC = 3651.901). In the maximum likelihood tree all the species formed reciprocally monophyletic groups (Fig.
Species | [1] | [2] | [3] | [4] |
Indoreonectes evezardi [1] | 0.0–0.2 | |||
Indoreonectes neeleshi [2] | 6.8–8.1 | 0.0–0.8 | ||
Indoreonectes rajeevi [3] | 12.4–13.5 | 10.9–12.5 | 0.0–1.1 | |
Indoreonectes keralensis [4] | 14.2–14.8 | 13.7–14.4 | 14.0 | 0.0 |
Species | [1] | [2] | [3] | [4] | [5] |
Indoreonectes evezardi [1] | 0.0–0.6 | ||||
Indoreonectes neeleshi [2] | 5.7–5.9 | 0.1 | |||
Indoreonectes rajeevi [3] | 11.8–11.9 | 13.2–13.3 | 0.0 | ||
Indoreonectes telanganaensis [4] | 6.6–6.8 | 6.5–6.7 | 13.1–13.2 | 0.1 | |
Indoreonectes keralensis [5] | 16.0–16.1 | 16.1–16.2 | 15.8 | 15.7 | 0.0 |
Genetically, the new species are quite distinct from their congeners. Although the genetic data for cox1 gene are not available for I. telanganaensis, both I. neeleshi and I. rajeevi are distinct from it in cytb gene sequence. For loaches, the interspecific genetic distances for cytb gene have been observed to range from 2.0% in Balitoridae (
Consistent with the arguments raised by
Indoreonectes keralensis: Paratypes, ZSI FF 1326, 3 ex., Pampadumpara, Periyar River, Kerala, India, coll. S. D. Rita, 1976 (only photographs examined); KUFOS.2017.11.217 (Fig.
Indoreonectes telanganaensis: Data from
The authors are grateful to Sanjay Molur for his encouragement, Ashwini Keskar for her support during the studyand Anoop V. K. for providing specimens of Indoreonectes keralensis. Authors also thank Rahul Khot, Assistant Director, Natural History Collections department, for his help during the registration of specimens in BNHS, Mumbai. The critical comments and suggestions of the anonymous reviewers and Ralf Britz greatly improved the manuscript.
Sequences used for genetic analysis, with localities and GenBank accession numbers.
Species | Location | Latitude (N) | Longitude (E) | coxI | cytb | Reference |
Indoreonectes neeleshi | Harishchandragad, MH | 19.394 | 73.779 | MW136273 | — | Current Study |
Indoreonectes neeleshi | Harishchandragad, MH | 19.507 | 73.698 | KX384756 | KY497100 |
|
Indoreonectes neeleshi | Harishchandragad, MH | 19.507 | 73.698 | KX384757 | KY497101 |
|
Indoreonectes rajeevi | Amboli, MH | 15.967 | 74.011 | MW136274 | — | Current study |
Indoreonectes rajeevi | Ajara, MH | 16.14 | 74.206 | KX946668 | — |
|
Indoreonectes rajeevi | Ajara, MH | 16.14 | 74.206 | KX946669 | — |
|
Indoreonectes rajeevi | Ajara, MH | 16.14 | 74.206 | KX946670 | — |
|
Indoreonectes rajeevi | Amboli, MH | 16.1 | 74.123 | KX384748 | — |
|
Indoreonectes rajeevi | Amboli, MH | 16.1 | 74.123 | KX384749 | KY497093 |
|
Indoreonectes keralensis | Erratayar, KL | 9.799 | 77.106 | MG018976 | MG018981 |
|
Indoreonectes evezardi | Pune, MH | 18.436 | 73.635 | KX384763 | KY497107 |
|
Indoreonectes evezardi | Pune, MH | 18.472 | 73.808 | KX384764 | KY497108 |
|
Indoreonectes evezardi | Pune, MH | 18.472 | 73.808 | KX384765 | KY497109 |
|
Indoreonectes telanganaensis | Maisamma Loddi, TS | 19.192 | 78.977 | — | MT569389 |
|
Indoreonectes telanganaensis | Maisamma Loddi, TS | 19.192 | 78.977 | — | MT569390 |
|
Balitora chipkali | Joida, KA | 15.342 | 74.441 | KU378004 | KU378017 |
|