Petrocephalus pallidomaculatus Bigorne and Paugy, 1991
Species overview
Small fish, body moderately short and deep, head about as long as deep, snout short, much less than diameter of eye, upper contour much stronger curved than lower, mouth inferior. Particular aggregations of cutaneous sensory organs not indicated. Body silvery, live with pale but fading markings. Size observed: 85 mm SL.
P. pallidomacul.(measurements)
Taxonomic description
-Body moderately short, strongly laterally compressed, body depth 29-33 % SL, greatest depth above origin of anal fin.
-Head length 22-25 % SL; head depth not indicated.
-Outline of back more or less straight, upper profile and underside of head convex, outline of belly slightly convex, base of unpaired fins moderately steep running to caudal peduncle.
-Snout rounded, short, 14-19 % head length.
-Mouth size not indicated, inferior, its edge below centre of eye, upper jaw on a level with upper edge base of pectoral fin.
-Chin inconspicuous.
-Teeth notched, 5-10/12-20.
-Nostrils closely together, upright-oval, on a level with lower rim of lens; axis parallel to axis of head.
-Eye quite large, diameter 31-34 % head length. Presence or absence of particular aggregations of electrorecpetors on the head not indicated.
-Opercular cleft strongly curved, length not indicated.
-Dorsal fin 20-27 fin-rays, base of D 19-23 % SL, anal fin 27-34 rays, base of A 27-29 % SL, origin of D slightly behind origin of A, end of D before end of A; predorsal length 59-63 % SL, preanal length 55-60 % SL.
-Pectoral fin pointed, length, extending to middle of pelvic fin. V is closer to P than to A.
-Caudal fin pointed, scaled part round, short. 36-43 scales in lateral line; 12 round caudal peduncle.
-Caudal peduncle 16-19% SL, its depth 5.5-6 % SL, 30-38 % its length. (Data based on original description).
-Coloration Uniform silvery »?the first rays of the dorsal fin can be sligthly greyish; a grey spot, sometimes hardly perceptible, beneath the dorsal fin and clearly apart from it«. These markings tend to fade out after the fish has been caught and will hardly be found in preserved specimens.
Type locality
»Mali: Niger à Kalaban (près de Bamoko)« (Bamoko 12° 38 ‘ N 8° 00 ‘ W)
Distribution
Upper Niger up to central delta, Volta, Mono and Oueme basins; upper Senegal river.
Electric organ discharges
Biphasic, head positive, +/–
Duration from beginning to peak of negative phase: 17-29 µsec
Total duration of negative phase: 75-135 µsec
No sexual differences (Graff and Bigorne, 1990)