Petrocephalus catostoma catostoma (Günther, 1866)
Species overview
Small fish, body moderately deep, head slightly longer than deep, snout short, slightly shorter than diameter of eye; mouth inferior. Head with three aggregations, »rosettes«, of cutaneous sensory organs. Caudal peduncle rather long and deep. Coloration silvery, countershaded, without markings on body or fins. Size observed: 104.5 mm SL.
P. cat. catostoma(measurements)
Taxonomic description
-Body moderately short, strongly laterally compressed, body depth 28-38 % SL, greatest depth above origin of anal fin.
-Head length 26-30 % SL; head depth 22-29 % SL, 71-82 % body depth.
-Outlines of back and of belly slightly convex. upper profile and underside of head convex, bases of unpaired fins running steeply to caudal peduncle.
-Snout rounded, rather blunt, short, 13-20 % head length, 21-32 % postorbital length
-Mouth width 18-25 % head length, inferior, its edge below centre of eye, upper jaw on a level with lower edge of opercular cleft.
-Chin inconspicuous.
-Teeth notched, 12-16/18-24.
-Nostrils closely together, upright-oval, on a level with lower rim of the lens of the eye, axis parallel axis of head, distance between nostrils half their distance from eye.
-Eye diameter 16-22 % head length, 27-38 % postorbital length. Three rosettes, aggregations of electrorecpetors, on the head. Opercular cleft strongly curved, its caudal margin posterior to base of pectoral fin, its length, i. e. distance between upper and lower edge, 33-49 % head length, 41-58 % head depth.
-Dorsal fin 19-22 fin-rays, base of D 16-20 % SL, anal fin 25-29 rays, base of A 21-28 % SL, origin of D behind origin of A, end of D well before end of A; predorsal length 59-67 % SL, preanal length 56-62 % SL.
-Pectoral fin pointed, extending to 1/2 or 3/4 the length of pelvic fin. V is closer to P than to A.
-Caudal fin pointed, scaled part short. 35-41 scales in lateral line; 12 or 16 round caudal peduncle.
-Caudal peduncle 18-25% SL , its depth 6-9 % SL, 33-44 % its length.
-Coloration »Silvery, back dark brown, grey, black or blackish« countershaded, fins grey or colourless.
Type locality
P. catostoma catostoma: »Rovuma River« Tanzania = Ruvuma river (10° 29 ‘ S 40° 28 ‘ E)
P. degeni: »Mouth of the Katonga River« Lake Victoria (0° 10 ‘ N 30° 40 ‘ E)
P. stuhlmanni: »Kingani River, East Africa« = Rufu / Ruvu river (6° 48 ‘ S 38° 39 ‘ E).
Distribution
»Eastward flowing rivers of Africa«. »Zimbabwe - The entire Zambezi system and the lower Save/Runde. ?Zimbabwean section of the Limpopo and Buzi rivers? - Victoria Nile, Lakes Victoria and Nabugo, Tana River, Ruvuma, Zambezi, Zaire, Cunene, Okanvango, Zambian Zaire system, Lake Malawi and down the east coast as far as the lower Pongola in Zululand«. Bell-Cross and Minshull, 1988.