Peppered Horseface Loach

description

Description. As in description of genus; Tables 1, 2, 4. Head long (24.1 – 26.9 % SL); snout long (58.8 – 65.9 % HL); 2, rarely 3, pairs of labial barbels; 10 ½, rarely 11 ½, branched dorsal rays; 10, less often 9 or 11, pectoral rays; 29 – 31 abdominal + 10 – 13 caudal = 41 – 42 total vertebrae. Maximum SL = 116.7 mm, TL = 139.1 mm (UF 188116). Color. Dark spots in 1 or 2 rows on top of head; no or few scattered small spots on side of head; none large. Black line from eye to tip of snout. Eight – 17 dark saddles along dorsal midline to origin of caudal fin; 6 – 12 large dark spots or blotches along lateral line from head to caudal fin; many small dark spots or specks on upper side of body and on lower side of body just below midlateral row of dark spots from head to caudal fin. Fins usually without obvious bands; 2 – 3 faint bands on dorsal fin of large individuals. Dark upper and lower margins of caudal fin. No small bold black spot or ocellus near upper or lower margins of caudal-fin origin. Live individuals yellowish brown dorsally, white below, with large black blotches dorsally and laterally on body; iridescent yellow on side of head and lower fins. Sexual dimorphism. Males h

Revision of the horseface loaches (Cobitidae, Acantopsis), with descriptions of three new species from Southeast Asia

diagnosis

Diagnosis. Acantopsis dinema differs from all other species of Acantopsis (Table 4) by combination of no large spots on side of head, many black specks beneath midlateral row of black spots from head to caudal fin, 2 pairs of labial barbels, no distinct small black spot on upper margin of caudal-fin base, no large black spots on dorsal or caudal fins, usually 10 ½ branched dorsal rays and 10 pectoral rays, 8 – 17 dark saddles along dorsal midline, 6 – 12 black spots along side of body, 41 – 42 total vertebrae, body depth 12.0 – 14.5 % SL, body width 8.0 – 10.3 % SL, caudal-peduncle length 12.1 – 14.3 % SL. Comparisons. Acantopsis dinema is distinguished from all other species of Acantopsis by having a row of black specks beneath midlateral row of black spots (specks rarely present in A. dialuzona and A. rungthipae; absent in other species of Acantopsis), and from all species except A. octoactinotos by having no dark spots on side of head (vs. usually conspicuous dark spots or specks on side of head). It further differs from A. rungthipae and A. ioa by having 2 (vs. 0) pairs of labial barbels, usually 10 ½ (vs. 9 ½) branched dorsal rays; from A. rungthipae by lacking distinct small

Revision of the horseface loaches (Cobitidae, Acantopsis), with descriptions of three new species from Southeast Asia

distribution

Distribution. Acantopsis dinema is widespread and common in the tributaries of the Mekong River draining the Khorat Plateau and Mekong Delta ecoregions (Abell et al. 2008) in Thailand, Laos, and Cambodia (Fig. 18), from the Songkhram River in eastern Thailand to the Prek Thnot River south of Phnom Penh, Cambodia.

Revision of the horseface loaches (Cobitidae, Acantopsis), with descriptions of three new species from Southeast Asia

etymology

Etymology. The epithet dinema, from Latin, di meaning two, and nema, for thread, refers to the usual presence of two pairs of labial barbels in this species.

Revision of the horseface loaches (Cobitidae, Acantopsis), with descriptions of three new species from Southeast Asia