| Distribution: |
Africa: in most coastal rivers from the Senegal to the Pra in Ghana (Ref. 7324, 57126), including rivers of Côte d'Ivoire (Ref. 272), Gambia, Guinea, Guinea-Bissau, Sierra Leone and Liberia (Ref. 13331). |
| Diagnosis: |
Dorsal spines (total): 2; Dorsal soft rays (total): 5-7; Anal spines: -0. Diagnosis: second or third branched dorsal-fin ray longest (except in juveniles in which the first is the longest), but never filamentous; adipose fin small, its base shorter than or equal to dorsal-fin base; high number of branched pectoral-fin rays (usually 9, rarely 8); 12-16 (most often 13 or 14) stout and crenulate gill rakers on lower limb of first gill arch; there are important differences among the various populations of this species, and sexual dimorphism is noticeable between mature specimens in reproductive activity and immature individuals, more pronounced in males than in females and increasing with growth (Ref. 57126).
Description: nasal barbels present; very short first dorsal spine; well developed second spine, weakly denticulate along posterior margin; pelvic fin with 1 unbranched and 5 branched soft rays; anal fin with 3-4 unbranched and 6-10 branched soft rays (Ref. 57126). There are important differences among the various populations of this species. One of the most variable characters is the length of dorsal and caudal fins: specimens from rivers usually have a longer dorsal fin than those from lakes and lagoons; adult specimens from the rivers Casamance, Lofa, Moa, St. Paul, St. John, Cess, Cavally, Sassandra and especially Bandama, have a dorsal fin reaching or exceeding (when pressed to body) the adipose fin. The number of gill rakers on the lower limb of first gill arch varies between 12 and 16, but most specimens have 13 or 14; the populations from the rivers Kakrima, Taja, Moa and Waanje have 14 or 15 lower gill rakers and are furthermore characterized by having a long snout (over 40% of head length), this proportion fluctuating between 30 and 40% in most of the other specimens (Ref. 57126). Sexual dimorphism is noticeable between mature specimens in reproductive activity and immature individuals, more pronounced in males than in females and increasing with growth. The width of the premaxillary tooth plate is less than 1/5 of head length in immature adults, but increases up to 1/3 of head length in mature individuals; the mouth width, which in immature specimens is smaller than, or equal to, snout length, increases up to 1.5 times the snout length; the palatine dentition, normally reduced to a few teeth or small bands, increases in adult males forming two long, straight bands; finally, the dorsal fin and spine become proportionally smaller, all fins more rounded, and the head, inflated (Ref. 57126).
Coloration: live specimens silvery, with brownish or greenish reflections (Ref. 57126). Preserved individuals: dark brown on head and back, whitish on belly; dorsal and caudal fins frequently finely black-edged; often a black spot behind gill cover; some specimens entirely black (Ref. 57126). |
