| Diagnosis: |
Dorsal spines (total): 0-0; Dorsal soft rays (total): 11-11; Anal spines: 0-0; Anal soft rays: 8-9; Vertebrae: 30-31. Diagnosis: This species is readily distinguished from all congeners by the presence of a flexible, weakly ossified, and smooth-bordered last unbranched dorsal-fin ray, well-developed barbels, and a straight and complete lateral line in combination with a characteristic pigmentation patterning consisting of a distinctive, rounded black spot at the base of and extending over the first rays of the anal fin and a prominent, darkly pigmented blotch over the base of the anterior dorsal-fin rays (Ref. 119360).
Description: Body moderately elongate, laterally compressed, although belly of ripe females often distended (Ref. 119360). Head small, eyes large, mouth subinferior, two pairs of barbels; in smaller specimens, less than 35 mm standard length, maxillary barbels extend to anterior third of eye, mandibular pair reach just beyond posterior margin of orbit; in larger specimens, maxillary pair extends posterior to level of mideye, mandibular pair reaches anterior border of preopercle; no tubercles or sensory pit lines present (Ref. 119360). Cranium fully ossified with no open occipital fontanel; five infraorbitals, first infraorbital deepest of the series, infraorbitals 2 to 5 tubular, with medially located infraorbital canal (Ref. 119360). Gill rakers small, 4-6 restricted to distal portion of ceratobranchial and epibranchial of first arch (Ref. 119360). Dorsal fin with 3 unbranched and 8 branched rays, positioned midway between snout and caudal-fin base, origin at, or slightly anterior to, pelvic-fin insertion; last unbranched ray long and weakly ossified, segmented distally, and lacking serrations along posterior border; anal fin with 3 unbranched and 5-6 branched rays; forked caudal fin, 9+10 principal rays, 6-8 + 7-9 procurrent rays; pelvic fin with 1 unbranched and 7 branched rays; pectoral fin with 1 unbranched and 12-13 branched rays (Ref. 119360). Scales radially striated; 23-26 in lateral line, and 1-2 over caudal-fin base; 4.5/1/3.5 transverse body rows; 11-12 circumpeduncular rows; 8.5-9.5 predorsal scale rows; lateral line complete, located along midline with pored scales not enlarged relative to those along impinging rows above and below (Ref. 119360). Total vertebrae 30-31, 16-17 abdominal, 14-15 caudal; 11-12 pleural ribs, 4-5 broad supraneurals located between and filling the interspaces of neural spines of vertebral centra 4-8; first dorsal-fin pterygiophore between neural spines of vertebral centrum 8-9, and first anal-fin pterygiophore directed at hemal spine of vertebral centra 17-19; caudal-fin rays supported by neural and hemal spines of pleural centra 2-3; pleurostyle, single epural, parhypural and 7 hypural elements present (Ref. 119360).
Colouration: In preservation, base body colouration cream or creamy yellow, darker dorsally, becoming paler ventrally over belly, cheeks, and lower jaws; snout and dorsum of head heavily pigmented and dark, opercular blotch usually well developed; prominent lateral band overlies a somewhat zigzag-patterned midlateral scale series; lateral band widest anteriorly, becoming somewhat attenuated posteriorly, terminating in round or ovoid caudal spot over line of caudal flexion, not extending onto caudal fin; darkly pigmented blotch over base of anterior dorsal-fin rays; prominent, rounded black spot at anterior base of, and extending onto, first few anal-fin rays; fins otherwise pale gray or hyaline (Ref. 119360). Base colouration in life somewhat variable, either predominately silvery or golden; opercular blotch and midlateral band only faintly visible, black pigmentation at anterior base of dorsal, anal and caudal fins strongly marked (Ref. 119360). |