Amblyceps cerinum, a new catfish (Teleostei: Amblycipitidae) from northeastern India
Author
Ng, Heok Hee
Author
Wright, Jeremy J.
text
Zootaxa
2010
2672
50
60
journal article
10.5281/zenodo.199168
1fea9910-68c2-48fd-8801-1e44d01f963c
1175-5326
199168
Amblyceps cerinum
sp. nov.
(
Fig. 1
)
Amblyceps mangois
(in part)—
Hora 1933
: 617
.
Amblyceps apangi
(non Nath & Dey)—
Sullivan
et al.
2008
: 64
;
Ng & Wright 2009
: 374
.
Type
material.
Holotype
:
UMMZ
248850,
72.8 mm
SL
;
India
, West Bengal, Raidak I River at Shipra, just outside Buxa Tiger Reserve approx.
8 km
toward Barobisha on Siliguri-Guwahati road,
26°31’12”N
,
89°43’25”E
; A. Rao,
30 January 2010
.
Paratypes
:
BMNH
1932.4.22.2–5 (3),
28.1–30.8 mm
SL
;
RMNH
16093 (2),
38.6–51.6 mm
SL
;
India
: West Bengal, Sevoke stream, Tista Valley; S. L. Hora,
February 1931
.
CAS-SU
69784 (1),
42.8 mm
SL
;
India
: West Bengal, Kalimpong Duars and Siliguri Terai; S. L. Hora,
November 1938
.
UMMZ
248834 (4), 59.0–
89.2 mm
SL
; collection data as for
holotype
.
UMMZ
248835 (21),
61.4–97.3 mm
SL
; locality data as for
holotype
; A. Rao,
23 March 2010
.
UMMZ
244754 (7), 30.0–83.0 mm
SL
; locality data as for
holotype
; H. H. Ng
et al.
,
13 April 2004
.
Diagnosis.
Amblyceps cerinum
differs from all congeners except
A. apangi
,
A. murraystuarti
, and
A. torrentis
in having a truncate (vs. forked or strongly emarginate) caudal fin. It differs from
A. apangi
in having a longer adipose-fin base (32.4–38.3% SL vs. 24.3–32.0), a more slender caudal peduncle (9.2–11.2% SL vs. 11.3–15.4), a greater number of post-Weberian vertebrae (41–44 vs. 38) and in having the lateral line terminating just posterior to the vertical through the dorsal-fin insertion (vs. extending to the end of the caudal peduncle), from
A. murraystuarti
in having a more slender body (9.2–11.2% SL vs. 11.6–15.0), a longer caudal peduncle (21.9–24.5% SL vs. 19.6–22.6) and the posterior end of the adipose fin not broadly confluent with the dorsal procurrent caudal-fin rays and separated from them by a distinct notch (vs. adipose fin broadly confluent with dorsal procurrent caudal-fin rays and not separated by a distinct notch), and from
A. torrentis
in having a more slender body (9.2–11.9% SL vs. 15.3–17.3% SL) and caudal peduncle (9.2–11.2% SL vs. 13.8– 15.6), the upper jaw longer than the lower jaw (vs. jaws equal), and an incomplete lateral line terminating at the posterior base of the dorsal fin (vs. a complete lateral line terminating at the base of the caudal fin).
Description.
Biometric data in
Table 1
. Body elongate, semi-cylindrical anterior to pelvic fins, compressed posterior to pelvic fins. Predorsal profile convex; gently sloping ventrally from dorsal-fin origin to tip of snout; contour smooth except for noticeable notch formed by origin of jaw adductor muscles on skull. Postdorsal profile relatively straight from dorsal-fin insertion to vertical through anal-fin origin, becoming gently convex posterior to vertical through anal-fin origin. Preanal profile convex from tip of snout to vertical through dorsal-fin origin, becoming convex from vertical through dorsal-fin origin to anal-fin origin. Postanal profile straight or slightly concave. Skin on flanks, head, and all fins covered with small, granular papillae, clearly visible under magnification. Lateral line incomplete, terminating at point slightly posterior to vertical through dorsal-fin insertion. No discernible difference in urogenital morphology between males and females.
TABLE 1.
Biometric data for
Amblyceps cerinum
(n=25).
| Holotype |
Range |
Mean±SD |
| Standard length (mm) |
72.8 |
59.0–97.3 |
| %SL |
| Predorsal length |
26.9 |
22.8–29.2 |
26.1±1.82 |
| Preanal length |
63.3 |
62.7–67.1 |
65.0±1.45 |
| Prepelvic length |
48.1 |
46.6–50.6 |
48.3±1.00 |
| Prepectoral length |
20.9 |
16.3–22.9 |
20.2±2.19 |
| Length of dorsal-fin base |
7.1 |
6.2–8.7 |
7.5±0.84 |
| Dorsal-spine length |
6.7 |
5.0–8.9 |
7.3±1.18 |
| Length of anal-fin base |
12.1 |
10.6–13.6 |
12.1±0.86 |
| Pelvic-fin length |
8.8 |
7.2–9.5 |
8.4±0.71 |
| Pectoral-fin length |
10.4 |
10.0–11.6 |
10.9±0.62 |
| Pectoral-spine length |
6.9 |
5.7–8.5 |
6.8±0.95 |
| Caudal-fin length |
14.7 |
14.0–18.0 |
16.2±1.30 |
| Length of adipose-fin base |
33.9 |
32.4–38.3 |
34.8±1.90 |
| Dorsal to adipose distance |
29.7 |
26.8–33.3 |
30.0±2.29 |
| Length of caudal peduncle |
23.8 |
21.9–24.5 |
23.4±0.99 |
| Depth of caudal peduncle |
9.8 |
9.2–11.2 |
9.9±0.59 |
| Body depth at anus |
11.7 |
9.2–11.9 |
10.4±0.95 |
| Head length |
23.8 |
19.8–24.3 |
22.6±1.64 |
| Head width |
13.0 |
12.4–16.4 |
14.3±1.29 |
| Head depth |
7.0 |
7.0–9.2 |
8.3±0.72 |
| %HL |
| Snout length |
34.7 |
33.1–43.1 |
37.7±3.22 |
| Interorbital distance |
20.2 |
20.2–26.7 |
23.3±2.17 |
| Eye diameter |
5.2 |
5.1–8.1 |
6.0±1.02 |
| Nasal barbel length |
33.5 |
31.5–48.3 |
38.9±5.41 |
| Maxillary barbel length |
78.6 |
78.6–110.1 |
88.5±10.35 |
| Inner mandibular barbel length |
35.3 |
30.8–51.7 |
40.5±6.19 |
| Outer mandibular barbel length |
64.2 |
49.4–79.4 |
79.4±67.4 |
FIGURE 1.
Amblyceps cerinum
, holotype, UMMZ 248850, 72.8 mm SL; India: West Bengal, Raidak I River.
FIGURE 2.
Amblyceps cerinum
, paratype, UMMZ 248835, 59.0 mm SL, showing yellowish color in life.
Head depressed, broad, wedge-shaped in lateral profile. Snout long, acutely triangular when viewed laterally, broadly rounded when viewed dorsally. Anterior nostril located at base of nasal barbel, forming short, ovaline tube. Anterior margin of posterior nostril confluent with posterior base of nasal barbel; posterior margin surrounded by short flap of skin. Gill membranes narrowly joined at isthmus. Eye located dorsally, well posterior of nasal barbel, subcutaneous, ovoid, horizontal axis longest. Interorbital area markedly concave.
FIGURE 3.
Map of Indian subcontinent showing collecting locality of
Amblyceps cerinum
(circle) and type locality of
A. tenuispinis
(triangle).
Mouth subterminal, upper jaw extending well beyond lower, lips thickened and papillate. Premaxillary teeth short, conical, posteriorly directed; arranged in semi-rectangular band with well developed posterior extensions. Mandibular teeth small, conical, arranged in narrow crescentic band. Maxillary barbel short, when adpressed reaching just beyond origin of pectoral fin. Nasal barbel short, when adpressed posteriorly, reaching far beyond posterior margin of eye. Lateral mandibular barbel reaching to posterior base of pectoral fin. Medial mandibular barbel short, less than ¼ length of head. All barbels lacking membrane.
Dorsal fin i,5 (4) or i,6 (21)*, origin at vertical through middle of pectoral fin; first element flexible, incompletely ossified. Pectoral fin i,7 (23)* or i,8 (2), first element flexible, incompletely ossified. Pelvic fin with i,5 (25) rays, located approximately at vertical through midpoint between dorsal-fin insertion and adipose-fin origin. Anal fin with iv,8 (3), iv,9 (4), v,8 (10)* or v,9 (6) elements, margin rounded, origin at point 1/3 distance between pelvic-fin origin and caudal-fin origin. Caudal fin with x,7,8,xii (1), xi,8,8,xi (2), xi,8,8,xii (4), xi,8,8,xiii (1), xii,8,7,xii (1), xii,8,8,xi (1), xii,8,8,xii (10)*, xii,8,8,xiii (1), xii,8,9,xiii (1) or xiii,8,8,xiii (1) rays; emarginate; upper lobe slightly longer than lower, terminating in short filament. Adipose fin long, low, upper margin convex; origin at vertical midway between adpressed tip of pelvic fin and anal-fin origin. Vertebral column with 41 (6), 42 (9)*, 43 (6) or 44 (3) post-Weberian vertebrae.
Coloration.
In 70% ethanol: Dorsum and upper flanks reddish beige to light gray. Lower flanks beige, trending lighter toward cream-colored belly. Nasal and maxillary barbels with gray basally, becoming lighter distally. Mandibular barbels cream colored. Dorsum coloration extending onto base of dorsal and adipose fins; both fins with lighter outer margin, very thin on adipose fin. Pectoral, pelvic, and anal fins with very faint pigmented area at base, otherwise uniformly cream colored. Caudal fin uniformly dusky, upper rays slightly more so than lower. Live color similar, but with a strong brownish- or orange-yellow hue (
Fig. 2
).
FIGURE 4.
Type locality of
Amblyceps cerinum
(Raidak I River). Photograph courtesy of Antti Vuorela.
Distribution and habitat.
Amblyceps cerinum
is known only from the Brahmaputra River drainage in northern West Bengal,
India
(
Fig. 3
). The
type
locality is a shallow, swift-flowing stream with a substrate of cobble and sand (
Fig. 4
). The fish were frequently found under cobble.
Etymology.
The specific epithet derives from the Latin adjective
cerinus
, meaning wax-colored. This name is used in allusion to the yellowish coloration in life of this species.