Corresponding author: Pradeep Kumkar (kumkarpradeep@gmail.com)
Academic editor Ralf Britz
The hill stream loach genus
The genus
Based on extensive genetic sampling from the northern Western Ghats,
In the current study we redescribe
Individuals of the new species of
Type localities of species of the genus
Measurements were taken for each specimen to the nearest 0.1 mm using digital callipers (Mitutoyo, Japan). Morphometric methods follow
Diagram of colour markings in
Two paratypes of
Gill tissues were extracted from a paratype of each species preserved in absolute alcohol (
Gene sequences were aligned with MUSCLE (
BNHS FWF 1068–1070, 3 ex., 33.1–43.81 mm
General morphology is shown in Figure
Morphometric data of
|
|
|
|
||||||
|
|
|
|
|
|
|
|
||
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 ( |
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 ( |
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 | |
% |
|||||||||
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 | |
% |
|||||||||
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
Mouth of
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
Cleared and stained fifth ceratobranchials showing dentition pattern, in dorsal view. (
In life (Fig.
The types of
BNHS FWF 1071, 38.54 mm
BNHS FWF 1072–1080, 9 ex., 28.2–36.3 mm
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
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.
BNHS FWF 1081, 45.76 mm
BNHS FWF 1082–1092, 11 ex., 26.4–36.3 mm
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
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 (
The type species of the genus
Based on the comparison provided above, the species of
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 |
|
– | 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 | 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 |
|
– | 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 | Lateral bars wider than inter-bar spaces |
|
– | Lateral bars narrower than inter-bar spaces |
|
4 | Caudal peduncle as long as deep; caudal-peduncle bar not divided into two spots; spots on cheeks below eye |
|
– | Caudal peduncle deeper than long; caudal-peduncle bar expressed as two separate spots; no spots on cheeks below eye |
|
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
Maximum likelihood phylogram based on
Percentage raw genetic distances in cytochrome oxidase subunit 1 gene.
|
[ |
[ |
[ |
[ |
|
||||
6.8–8.1 | ||||
12.4–13.5 | 10.9–12.5 | |||
14.2–14.8 | 13.7–14.4 | 14.0 |
|
Percentage raw genetic distances in cytochrome b gene.
|
[ |
[ |
[ |
[ |
[ |
5.7–5.9 |
|
||||
11.8–11.9 | 13.2–13.3 | 0.0 | |||
6.6–6.8 | 6.5–6.7 | 13.1–13.2 |
|
||
16.0–16.1 | 16.1–16.2 | 15.8 | 15.7 |
|
Genetically, the new species are quite distinct from their congeners. Although the genetic data for
Consistent with the arguments raised by
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
Sequences used for genetic analysis, with localities and GenBank accession numbers.
|
|
|
|
|
|
|
|
Harishchandragad, MH |
|
|
|
— | Current Study |
|
Harishchandragad, MH |
|
|
|
|
|
|
Harishchandragad, MH |
|
|
|
|
|
|
Amboli, MH |
|
|
|
— | Current study |
|
Ajara, MH |
|
|
|
— |
|
|
Ajara, MH |
|
|
|
— |
|
|
Ajara, MH |
|
|
|
— |
|
|
Amboli, MH |
|
|
|
— |
|
|
Amboli, MH |
|
|
|
|
|
|
Erratayar, KL |
|
|
|
|
|
|
Pune, MH |
|
|
|
|
|
|
Pune, MH |
|
|
|
|
|
|
Pune, MH |
|
|
|
|
|
|
Maisamma Loddi, TS |
|
|
— |
|
|
|
Maisamma Loddi, TS |
|
|
— |
|
|
|
Joida, KA |
|
|
|
|
|