Lepidocephalus pallens ( Vaillant, 1902 )

Deein, Gridsada, Tangjitjaroen, Weerapongse & Page, Lawrence M., 2014, A revision of the spirit loaches, genus Lepidocephalus (Cypriniformes, Cobitidae), Zootaxa 3779 (3), pp. 341-352 : 347-348

Lepidocephalus pallens ( Vaillant, 1902)

Pallid Spirit Loach

( Fig. 1C )

Lepidocephalichthys pallens Vaillant, 1902:153 . Type locality "Bords du Kapoeas (Sintang?)" [ Kapuas River (at Sintang?)]. Holotype: RMNH 7783 .

Diagnosis. A species of Lepidocephalus that is readily distinguishable ( Fig. 1 , Table 1 ) from all other species of Lepidocephalus by having the dorsal-fin origin over the pelvic-fin origin (vs. dorsal-fin origin behind the pelvic-fin origin), and a concomitantly shorter predorsal length (59.9 vs. 62.4–71.3% SL). Lepidocephalus pallens further differs from L. pahangensis in having scales on top of the head, and from L. spectrum by the presence of eyes and darker pigment on the body, and absence of tubules along the lateral line.

Description. Body deep, slab-sided; greatest depth 17.4% SL. Head narrow, length 23.2% SL. Eye small, in dorsal half of head in shallow depression above bifid suborbital spine. Origin of dorsal fin over origin of pelvic fin. No axillary lobe on pelvic fin. Small fleshy lobe at origin of pectoral fin.

Scales on top of head, cheek and opercle; body completely covered with minute, partially embedded scales. Lateral line complete, ~200 scales along lateral line; no tubules along lateral line. Mouth horseshoe-shaped; upper lip without median indentation; lower lip with median indentation on lower edge. Two pairs of rostral barbels; inner pair reaching to corner of mouth, outer pair slightly longer and reaching slightly past corner of mouth; one pair of maxillary barbels, reaching approximately to vertical at posterior end of groove containing suborbital spine. Large flap on anterior nostril. Dorsal rays iii,8; pectoral rays 11; pelvic rays 7; anal rays ii,5; upper branched caudal rays 7; lower branched caudal rays 7; vertebrae 28 abdominal + 15 caudal = 43 total ( Roberts 1989:96).

Only specimen known is the holotype, which appears to be a female. The pectoral fin is falcate with the 2 nd ray longer but not thicker than other rays (20.0% SL). Pelvic fin small, but larger than in other species at 11.5% SL.

Coloration in life. Described as pallid by Vaillant (1902).

Distribution. Known only from the type locality, the Kapuas River presumably at Sintang ( Fig. 2 ).

Remarks. Roberts (1989) treated L. pallens as a synonym of L. macrochir . However, as noted above, the two species are easily distinguished by the position of the dorsal-fin origin relative to that of the pelvic-fin origin ( Fig. 1 ). Lepidocephalus pallens and L. spectrum were both described from the Kapuas River in Borneo, and possibly occur syntopically.

Figures

FIGURE 1. Species of Lepidocephalus. (A) L. nanensis, holotype, NIFI 4388, 72.0 mm SL, Nan River, Thailand; (B) L. macrochir, syntype, BMNH 1866.5.2.55, 77.7 mm SL, Sumatra or Java; (C) L. pallens, holotype, RMNH 7783, 41.9 mm SL; (D) L. pahangensis, holotype, ZRC 490, 35.8 mm SL; (E) L. spectrum, paratype, USNM 230267, 49.2 mm SL, Kalimantan. Photos A, C, D and E by Z. Randall; B by M. Sabaj Perez.

FIGURE 2. Distribution of specimens of Lepidocephalus examined.