Diagnosis |
Diagnosis: Mouth terminal; one pair of barbels or none (Ref. 81639). West African specimens usually without barbels, but some adults may have one or two more or less well developed pairs; anterior barbel missing or not reaching to anterior margin of eye; posterior barbel missing or not reaching to anterior margin of eye; last simple dorsal-fin ray smooth on hind margin (Ref. 81282). 2-3 large gill rakers followed by undifferentiated papillate tissue on lower limb of first gill arch (Ref. 81639). Scale formula 3.5-4.5/22-25/2.5-3.5; 1.5 scales between lateral line and pelvic-fin insertions; 9-10 scales around caudal peduncle; lateral line usually incomplete; 8 branched dorsal fin rays (Ref. 81282, 81639). Lateral line deeply depressed below dorsal fin and lateral line scales deeper than other scales; maximum reported size 28 mm standard length; dorsal fin colorless; 3 small black spots aligned along middle of sides, one at end of caudal peduncle, other 2 below origin and below end of dorsal-fin base, respectively (but some of these spots may occasionally be missing) (Ref. 2940, 81282).
Description: Small species; mouth terminal and oblique, its angle located approximately below centre of eye (Ref. 81282, 81639). One pair of barbels or none (Ref. 81639, 122753); development of barbels occurs at late stage in Nile basin (Ref. 50093), where largest specimens may have two pairs of well-developed barbels (Ref. 81282); in West Africa majority of individuals lack barbels, except for some specimens that had been classified in different species (B. gourmanensis and B. karoualensis, which have two pairs of barbels) (Ref. 2940, 81282). Dorsal fin with 3 unbranched and 8 branched rays; anal fin with 3 unbranched and 5 branched rays; pectoral fin with 13 rays; pelvic fin with 8 rays (Ref. 81282, 81639). Scales: 3.5-4.5 scales between lateral line and dorsal fin origin; 2.5-3.5 scales between lateral line and mid-belly; 22-25 scales in lateral line; 1.5 scales between lateral line and pelvic fin insertion (Ref. 81282, 81639).
Colouration: Yellowish-white in life; fine, black longitudinal line and 3 small, rounded spots aligned along middle of sides; 1st before level of first dorsal-fin ray, 2nd below last dorsal-fin ray and 3rd at end of caudal peduncle; small black spots at base of anal fin; spots on flanks may or may not be visible, depending on individuals (Ref. 2940, 81282, 81639). |