Stomatorhinus polli Matthes, 1964
Species overview
Very small fish, body moderately elongate and deep, head slightly longer than body depth, longer than deep, snout truncate, feebly protruding mouth which is slightly subterminal; caudal peduncle short and deep. Uniform purplish black. Size observed: 63 mm SL, 73 mm TL.
S. polli(measurements)
Taxonomic description
-Body moderately elongate and deep, laterally compressed, body depth 25-29 % SL, greatest depth near middle of body.
-Head length 26-31 % SL; head depth 20-25 % SL, 73-94 % body depth.
-Outline of back rather straight, upper profile of head convex, straight or feebly concave above the eye, underside of head feebly concave, outline of belly slightly convex.
-Snout truncate, 13-20 % head length, 18-30 % postorbital length.
-Mouth 15-21 % head length, slightly subterminal, its edge below anterior rim of the eye, upper jaw on a level between origin of pectoral fin and underside of head.
-Chin inconspicuous.
-Teeth notched, 7/8.
-Nostrils clearly separate, posterior nostril oval, anterior on a level with centre of eye, posterior nostril close to edge of mouth.
-Eye diameter 7-11 % head length, 9-18 % postorbital length.
-Opercular cleft curved 26-41 % head length, 34-50 % head depth.
-Dorsal fin 16-20 fin-rays, base of D 22-23 % SL, anal fin 20-23 rays, base of A 24-28 % SL, origin of D behind origin of A, end of D more or less opposite end of A; predorsal length 60-65 % SL, preanal length 56-62 % SL.
-Pectoral fin obtusely pointed, extending to middle of pelvic fin. V is closer to P than to A.
-Caudal fin rounded, the scaled lobes rounded, extending over about 1/4 the length of the fin. 48-56 scales in lateral line, only 27-31 with pores; (12) 14-16 scales round caudal peduncle.
-Caudal peduncle 14-19 % SL, its depth 6-7 % SL, 27-44 % its length.
-Coloration »Uniform purplish-black, fins included; the fin-rays intensely blackish as in all the species of the genus«.
Type locality
»Yangambi« (0° 47 ‘ N 24° 28 ‘ E) Haut-Zaïre, district of Democratic Republic of Congo.
Distribution
Congo basin (type locality), Democratic Republic of Congo.