Petrocephalus squalostoma (Boulenger, 1915)
Species overview
Very small fish, body moderately short and deep, head as long as or slightly longer than deep, snout short, mouth inferior. Head with three aggregations, »rosettes«, of cutaneous sensory organs. Dorsal fin, base, shorter than anal. White, countershaded, with blackish dots. Size observed: 76 mm SL.
P. squalostoma(measurements)
Taxonomic description
-Body moderately short, strongly laterally compressed, body depth 29-35 % SL, greatest depth above pelvic fin.
-Head length 24-31 % SL; head depth 24-27 % SL, 78-84 % body depth.
-Outlines of back and belly slightly convex, upper profile of head convex, underside of head concave; bases of unpaired fins moderately steep running to caudal peduncle.
-Snout rounded, short, 10-18 % head length, 17-28 % postorbital length.
-Mouth 15-22 % head length, inferior, its edge below centre of eye, upper jaw on a level with lower edge base of pectoral fin.
-Chin inconspicuous.
-Teeth not indicated.
-Nostrils not very closely together, but still as typical for the genus, upright-oval, on a level with lower rim of eye; axis parallel to axis of head.
-Eye diameter 15-24 % head length, 24-38 % postorbital length. Three rosettes, aggregations of electrorecpetors, on the head.
-Opercular cleft strongly curved, 40-45 % head length, 44-51 % head depth.
-Dorsal fin 18-20 fin-rays, base of D 17-19 % SL, anal fin 29-31 rays, base of A 25-26 % SL, origin of D well behind origin of A, end of D well before end of A; predorsal length 59-64 % SL, preanal length 55-60 % SL.
-Pectoral fin obtusely pointed, extending to middle of pelvic fin. V is closer to P than to A.
-Caudal fin obtusely pointed, scaled part short. 39-42 scales in lateral line; 12 round caudal peduncle.
-Caudal peduncle short, 14-19 % SL, its depth 7 % SL, 36-47 % its length.
-Coloration »Brown above and on the flanks, blackish dotted, white beneath«. Countershaded.
Type locality
»Ruisseau affluent de la Lukinda«, Katanga, Shaba region; Democratic Republic of Congo.
Distribution
»Lukinda basin, tributary of Moero Lake (types locality)« (Lake Mweru (09° 00 ‘ S 28° 45 ‘ E) Democratic Republic of Congo.