Pollimyrus isidori osborni (Nichols and Griscom, 1917)
Species overview
Very small fish, body short and deep, head about as long as deep, snout rounded, short, slightly protruding mouth, caudal peduncle moderately long and deep. -Body purplish brown, head densely dotted dark, with paler greenish shine. Size observed: 66 mm SL.
P. i. osborni(measurement)
Taxonomic description
-Body short, strongly laterally compressed, body depth 30-37 % SL, greatest depth above pelvic fin.
-Head length 25-29 % SL; head depth 22-29 % SL, 73-87 % body depth.
-Outline of back slightly convex, upper profile of head strongly convex, underside of head convex, outline of belly slightly convex, base of dorsal fin running steeply to caudal peduncle, base of anal fin less steep.
-Snout blunt, rounded, 14-23 % head length, 22-40 % postorbital length.
-Mouth 14-23 % head length, subterminal, its edge below anterior rim of the lens, upper jaw on a level with or even below lower edge base of pectoral fin.
-Chin inconspicuous.
-Teeth feebly notched 5/8.
-Nostrils separate, circular, anterior nostril on a level with centre of eye, posterior nostril slightly below anterior, on a level slightly above lower rim of eye and close to its anterior rim. Axis of nostrils cutting axis of head at an angle of about 30°.
-Eye diameter 19-27 % head length, 32-47 % postorbital length. Opercular cleft curved, upper edge above base of pectoral fin, 27-36 % head length, 28-35 % head depth.
-Dorsal fin 16 fin-rays, base of D 19-22 % SL, anal fin 24 rays, base of A 24-31 % SL, origin of D well behind origin of A, end of D more or less opposite to end of A; predorsal length 58-62 % SL, preanal length 52-56 % SL.
-Pectoral fin pointed, extending to tip of pelvic fin. V is closer to P than to A.
-Caudal fin pointed, the scaled lobes rounded, short. 58 scales in lateral line; 14 round caudal peduncle.
-Caudal peduncle 18-23 % SL, its depth 5-7 % SL, 22-32 % its length.
-Coloration »Dark purplish brown, paler greenish on the head and nape«.
-Head densely spotted dark, spots increasing in size from front to gular region; bases of first rays of D and A as well as base of C dark.
Type locality
»Uele River«, Haut Zaïre, Democratic Republic of Congo (Uele river: 4° 09 ‘ N 22° 26 ‘ E)
Distribution:
»Middle Congo basin«.