Petrocephalus bovei (Valenciennes, 1846)
Species overview
Small fish, body deep, head a little longer than deep, shorter than body depth; snout short, shorter than diameter of eye, mouth inferior. Head with three aggregations, »rosettes«, of cutaneous sensory organs. Caudal peduncle rather short and deep. Uniform silvery with slightly darker back, fins colourless. Size observed: 100 mm SL, in guineensis 112 mm SL.
P. bovei(measurements)
Taxonomic description
-Body moderately short, deep, strongly laterally compressed, body depth 27-36 % SL, greatest depth at origin of anal fin.
-Head length 25-30 % SL; head depth 19-28 % SL, 61-82 % body depth.
-Outline of back and of belly slightly convex, upper profile and underside of head convex, bases of unpaired fins moderately steep running to caudal peduncle.
-Snout rounded, very short, 9-16 % head length, 14-27 % postorbital length.
-Mouth 16-23 % head length, inferior, its edge below centre of eye, upper jaw on a level with lower edge of opercular cleft.
-Chin inconspicuous.
-Teeth notched, 6-12/14-25.
-Nostrils closely together, upright-oval in shape, on a level slightly above lower rim of eye; axis parallel axis of head.
-Eye diameter 18-28 % head length, 30-48 % postorbital length. Three rosettes, aggregations of electrorecpetors, on the head.
-Opercular cleft strongly curved, 34-52 % head length, 36-53 % head depth.
-Dorsal fin 21-28 (mod. 23-26) fin-rays, base of D 17-23 % SL, anal fin 28-37 (mod. 31-33) rays, base of A 24-31 % SL, origin of D behind origin of A, end of D well before end of A; predorsal length 57-63 % SL, preanal length 51-59 % SL.
-Pectoral fin pointed, extending to 3/4 the length of pelvic fin. V is slightly closer to P than to A.
-Caudal fin pointed, scaled at the base. 37-43 scales in lateral line; 12 round caudal peduncle.
-Caudal peduncle 16-24 % SL, its depth 6-9 % SL, 30-50 % its length.
-Coloration Silvery, sometimes brilliantly or dim, even greyish or brownish, depending on local conditions.
Type locality
bovei: »Nil«,
brevipedunculatus: »Mac Carty Island, in swamps« Gambia River.
Distribution
Nile, Chad, Niger, Volta, Gambia and Senegal basins.
Electric organ discharges
Biphasic, head positive, +/– , followed by a feeble positive overshoot.
Duration from beginning to peak of negative phase: 13-31 µsec
Total duration of negative phase: 55-85 µsec. No sexual differences (Graff and Bigorne, 1990)
Remark on taxonomy
Reizer et al., 1973: 691, established a new subspecies, Petrocephalus bovei guineensis from the coastal range of Guinea to Ivory coast, without designation of a type, simply based on a lower fin-ray count in A: 28-32 in contrast to 30-37. There is no illustration going with the publication nor any other information. Bigorne and Paugy, 1991: 18 leave it open to consider this taxon as valid or not.