Pangasius sabahensis, Gustiano & Teugels & Pouyaud, 2003

Gustiano, R., Teugels, G. G. & Pouyaud, L., 2003, Revision of the Pangasius kunyit catfish complex, with description of two new species from South-East Asia (Siluriformes; Pangasiidae), Journal of Natural History 37 (3), pp. 357-376 : 372-375

Pangasius sabahensis sp. n.

(figure 8)

Pangasius kunyit (in part) Pouyaud et al., 1999: 251 (specimens from Kinabatangan River). Pangasius n. sp. 1 (in part) Pouyaud et al., 2000: 1513 (specimens from Kinabatangan).

HOLOTYPE. MZB 10848, 335 mm SL; from Sukau, Kinabatangan River , Sabah,

North Borneo ( Malaysia); A. Pariselle; October 1998 .

PARATYPES. Eleven specimens: MNHN 2001-0602 , 121–343 mm SL ; same data as holotype .

Diagnosis

Pangasius sabahensis is distinguished from all other Pangasius (Pangasius) species by the combination of the following characters: a broad and rounded head (snout length 44.2–49.6% HL; head depth 11.8–14.0% SL; head width 15.2–18.3% SL); the short distance from the snout to the isthmus (90.9–102.8% SNL); the long mandibular (56.0–66.0% HL) and maxillary (77.6–96.7% HL) barbels reaching beyond the posterior border of the operculum; a slender dorsal spine (width 4.4–5.7% SL); the posterior margin of the dorsal spine with 14–20 strong serrae; the pectoral spine with 16–19 strong serrae on the posterior margin; the short palatine toothplates (6.4–10.0% HL); and the presence of 19–23 gill rakers on the first branchial arch.

Description

Based on the holotype and 11 paratypes. The results of morphometrics taken on the type series are given in table 5.

Head broad and rounded in ventral profile and deep anteriorly. Snout long and elongated. Nostrils large; anterior nostrils entirely situated on anterior margin of upper lip; posterior nostrils located completely on dorsal surface of head; distance between anterior nostrils smaller than distance between posterior nostrils. Mouth large. Premaxillary toothplate visible when mouth closed; premaxillary teeth conical; vomerine toothplate large and slender, consisting of two separate patches in young, becoming fused ontogenetically; vomerine teeth submolariform; palatine toothplates short and slender throughout ontogeny; palatine teeth conical. Eyes latero-ventrally placed. Maxillary and mandibular barbels long, reaching beyond posterior border of operculum. Distance between snout and isthmus proportionally long. Gill rakers short, 19–23 (20 in holotype) on first branchial arch. Swimbladder with two chambers extending to above anterior portion of anal-fin base.

Body robust and broad. Dorsal with two spines; first very small, second long and slender. Dorsal-fin rays six or seven (seven in holotype). Posterior margin of dorsal spine with 14–20 strong serrae; numerous minute serrae on anterior margin. Pectoral-fin rays 9–12 (holotype nine). Pectoral spine robust with 16–19 strong serrae on posterior margin and no serrae on anterior margin. Pectoral fin not reaching vertical through base of last dorsal fin-ray basis. Six soft pelvic fin-rays; prepelvic distance proportionally long; dorsal, pectoral and pelvic fins with short extention at tip; anal fin short with 24–32 (32 in holotype) soft fin rays. Adipose fin of notable size, its length almost twice eye diameter. Caudal fin short and somewhat lobed.

Maximum observed size 343 mm SL.

Coloration

In live specimens, head and body sky-bluish grey dorsally; body sides silvery grey laterally and pale ventrally; dorsal, pectoral and anal fins yellowish or whitish.

Distribution

Pangasius sabahensis is endemic to northern Borneo and is presently known only from the type locality, the Kinabatangan River, Sabah State, Malaysia .

Habitat and ecology

Pangasius sabahensis is reported from estuarine areas. The species is omnivorous with a tendency towards piscivory increasing with age. Pangasius sabahensis occurs sympatrically with P. micronema and P. kinabatanganensis in the Kinabatangan River.

Etymology

Named after the Sabah State, in Malaysia, the region from which the type series originates .