Wetzone Butter Catfish

description

Description. For general appearance, see Figure 1; morphometric data are provided in Table 1. Body laterally compressed; body depth greatest at dorsal-fin origin; head as broad as body, slightly depressed. Dorsal profile of head evenly convex (Fig. 2 C). Anterior profile of snout rounded. Anterior nostril tubular, placed anteromedial to base of maxillary barbel. Posterior nostril bordered by fleshy dorsal and ventral membranes, placed posteromedial to base of maxillary barbel. Mouth terminal; lower jaw longer than the upper; gape almost horizontal, large; rictus beneath anterior orbital margin, separated from it by about a half-eye diameter. Rictal lobes well developed, subtended by deep submandibular groove. Thin supralabial fold extending from below orbit to base of maxillary barbel. Jaw teeth depressible, villiform. Premaxillary teeth in narrow, gently-curved bands. Dentary teeth similar, bands extending from symphysis almost to mouth corners. First of row of dentary teeth just visible with mouth closed. Palatal teeth in two gently-curved arc-shaped patches on either side of midline. O. argestes O. bimaculatus O. ceylonensis Pectoral-spine length 9.5 8.0 – 14.1 10.1 ± 1.8 8.6 –

Ompok argestes, a new species of silurid catfish endemic to Sri Lanka (Teleostei: Siluridae)

diagnosis

Diagnosis. Ompok argestes is distinguished from its Indian and Sri Lankan congeners by the combination of the following characters: body color pattern mottled; predorsal profile uniformly convex; maxillary barbels reach or extend slightly beyond the base of the dorsal fin; eye diameter 14.2 – 17.1 % head length; body depth at anus 19.8 – 22.3 % standard length (SL); head width 14.3 – 16.8 % SL; caudal peduncle depth 5.6 – 6.5 % SL; and vertebrae 48 – 52.

Ompok argestes, a new species of silurid catfish endemic to Sri Lanka (Teleostei: Siluridae)

etymology

Etymology. The specific epithet argestes is a Homeric (Greek) term for ‘ southwest’, a reference to the region of Sri Lanka in which the species occurs.

Ompok argestes, a new species of silurid catfish endemic to Sri Lanka (Teleostei: Siluridae)

materials_examined

Holotype: 2016.04.01. NH, 147 mm SL; Sri Lanka, Bentara River basin, Mathugama. H. Sudasinghe. Apr 2015. Paratypes: 2016.05.01. NH 110 mm SL; same data as holotype. 2016.05.02. NH, 92.5 mm SL, Sri Lanka, Kelani basin, Karawanella. H. Sudasinghe, Jan 2015. DZ 3199, 3200; same data as holotype. DZ 1380, 76.4 mm SL; Sri Lanka, Kalu basin, Dombagaskanda. H. Sudasinghe, Mar 2014. DZ 1395, 3049, 87.3 – 94.7 mm SL, Sri Lanka, Deduru Oya basin, tributary Kolamunu Oya. H. Sudasinghe, Jan 2015.

Ompok argestes, a new species of silurid catfish endemic to Sri Lanka (Teleostei: Siluridae)