Ompok karunkodu, Ng, Heok Hee, 2013

Ng, Heok Hee, 2013, Ompok karunkodu, a new catfish (Teleostei: Siluridae) from southern India, Zootaxa 3694 (2), pp. 161-166 : 161-164

Ompok karunkodu sp. nov.

( Fig. 1 )

Type material. Holotype: UMMZ 249905, 229.1 mm SL; India: Tamil Nadu, Amaravathi River in the vicinity of Amaravathi Dam, 10°24'N 77°16'E; A. Rao, January 2010.

Diagnosis. Ompok karunkodu can be distinguished from all congeners in the Indian subcontinent in lacking (vs. having) a process on the posteromedial edge of the coracoid, having a markedly convex predorsal profile (vs. with a slight or distinct concavity in the supraethmoidal or supraoccipital region), and a unique combination of the following characters: prognathous lower jaw causing snout to appear rounded when viewed laterally, maxillary barbel reaching to base of pectoral-fin spine, eye diameter 13.7% HL, head width 13.0% SL, body depth at anus 14.2% SL, 65 anal-fin rays, caudal peduncle depth 5.0% SL, caudal-fin length 12.6% SL, caudal fin with rounded lobes, 54 vertebrae, and dark midlateral stripe running along sides of body.

Description. Biometric data in Table 1. Body laterally compressed; maximum body depth located at dorsal-fin origin; head as broad as body and slightly depressed. Dorsal profile of head convex.

UMMZ 249905 Holotype

% SL

Predorsal length 29.3 Preanal length 30.3 Prepelvic length 28.1 Prepectoral length 19.1 Dorsal-fin base length 1.9 Anal-fin base length 68.0 Pelvic-fin length 6.8 Pectoral-fin length 14.6 Pectoral-spine length 5.6 Caudal-fin length 12.6 Body depth at anus 14.2 Caudal peduncle depth 5.0 Head length 19.1 Head width 13.0 Head depth 11.6 % HL

Snout length 38.6 Interorbital distance 48.2 Eye diameter 13.7 Maxillary barbel length 94.3 Mandibular barbel length 34.3

Anterior profile of snout rounded. Anterior pair of nostrils tubular and anteromedial to maxillary barbel base. Posterior pair of nostrils bordered by fleshy dorsal and ventral membranes and posteromedial to maxillary barbel base.

Mouth terminal; gape almost horizontal, large and extending between anterior orbital margins. Well-developed rictal lobes present, subtended by deep submandibular groove; upper rictal lobe without skin fold. Thin, broad supralabial fold extending from below orbit to maxillary barbel base.

Jaw teeth depressible and villiform. Premaxillary teeth in narrow, gently curved rectangular bands. Dentary teeth in similar, slightly narrower bands narrowing posterolaterally, reaching from symphysis almost to mouth corners. First row of dentary teeth slightly visible when mouth is closed. Palatal teeth in two gently curved arcshaped patches on either side of midline.

Two pairs of barbels, slightly flattened along entire length. Maxillary barbels reaching to base of pectoral-fin spine. Mandibular barbels (only outer pair present) reaching to one-third of distance between its base and base of pectoral-fin spine.

Eyes small, subcutaneous (without free orbital margin); located approximately midway on head and immediately behind supralabial fold. Dorsal orbital margin visible dorsally; ventral orbital margin not visible ventrally.

Gill membranes separate and overlapping, free from isthmus; gular fold well-developed and v-shaped. Branchiostegal rays 12. Gill rakers long and thin; anteriormost rakers on lower first arch widely spaced; 2+9.

Dorsal fin small, with i,3 rays. Depressed pectoral fin to base of second anal-fin ray; distal margin broadly convex, with rounded tip. Fifth branched pectoral ray longest and fin with 12 rays. Proximal two-thirds of first pectoral-fin element co-ossified into a slender spine. Spine with shallow oblique striae on dorsal and ventral surfaces; spine in females smooth and in males with 5–7 serrations on posterior edge spanning the distal end of the ossified and proximal end of the flexible distal tip. Axillary pore small, located just above pectoral spine base. Depressed pelvic fin reaching to base of first or second anal-fin ray; distal margin convex with i,6,i rays. Distal margin of anal fin straight, with 65 rays; separate from caudal fin. Integument over anal fin thickened proximally for approximately half of ray length; fin-ray erector muscles attaching to anterior edges of fin rays, ventralmost extent of muscles defined by area of thickened integument. Caudal peduncle slender. Caudal fin deeply forked, lobes elongate and with rounded tips; upper lobe slightly longer; principal rays i,7,8,i.

Lateral line complete, extending to middle of caudal-fin base, with short branches along flanks directed posteroventrally. Urogenital papilla located immediately posterior to insertion of pelvic fin. Vertebrae 13+41=54.

Coloration. In 70% ethanol: Body and head mottled brown, fading to cream ventrally. Humeral region with dark ovoid spot. Dark midlateral stripe running along sides of body, extending from posterior margin of humeral spot to middle of ural complex. Fin rays of dorsal, pectoral and caudal fins with scattering of melanophores, imparting dusky color to rays; all fin membranes devoid of melanophores. Maxillary barbels brown throughout; mandibular barbels cream.

Distribution. Known from the Amaravathi River (a right-hand tributary of the Kaveri River) in southern India ( Fig. 2).

Etymology. The specific epithet comes from the Tamil karun, a contraction of karuppu, meaning black and kodu, meaning line. This refers to the dark midlateral stripe running along the side of the body in this species. Used as a noun in apposition.

Figures

FIGURE 1. Ompok karunkodu, UMMZ 249905, holotype, 229.1 mm SL; India: Tamil Nadu, Amaravathi River.