Pollimyrus castelnaui (Boulenger, 1911)
Species overview
Very small fish, body moderately short and deep, head slightly shorter than body depth, slightly longer than deep; snout rounded, very slightly protruding mouth; caudal fin with short, rounded lobes. Brownish, countershaded, marbled and spotted black.
Size observed: 65 mm SL.
P. castelnaui(measurements)
Taxonomic description
-Body moderately short, strongly laterally compressed, body depth 25-31 % SL, greatest depth above pelvic fin or slightly behind.
-Head length 22-27 % SL; head depth 20-25 % SL, 69-85 % body depth.
-Outline of back slightly convex, upper profile of head strongly convex, underside of head convex, outline of belly slightly convex, bases of dorsal and anal fin steeply running to caudal peduncle.
-Snout blunt, rounded, feebly protruding mouth, 13-21 % head length, 19-35 % postorbital length.
-Mouth 15-24 % head length, slightly subterminal, its edge below posterior nostril, upper jaw on a level with upper edge of base of pectoral fin.
-Chin inconspicuous.
-Teeth notched, 7/8.
-Nostrils separate, circular, distance between nostrils much wider than distance from eye, anterior nostril on a level with lower rim of lens, posterior nostril on a level with lower rim of eye, their axis cutting axis of head at an angle of about 30°.
-Eye diameter 12-21 % head length, 17-35 % postorbital length.
-Opercular cleft curved, 27-46 % head length, 30-46 % head depth.
-Dorsal fin 17 fin-rays, base of D 18-21 % SL, anal fin 23 rays, base of A 21-26 % SL, origin of D behind origin of A, end of D more or less opposite end of A; predorsal length 59-66 % SL, preanal length 55-61 % SL.
-Pectoral fin pointed, extending to middle of pelvic fin. V is closer to P than to A.
-Caudal fin rounded, the rounded scaled lobes 1/5 as long as the membranous lobes. 48-50 scales in lateral line; 12 round caudal peduncle.
-Caudal peduncle 18-24% SL, its depth 4-8 % SL, 26-37 % its length.
-Coloration »Pale brownish, darker on the back, spotted and marbled with dark brown; fins brown«. Countershaded.
Type locality
»Lake Ngami«, (20° 37 ‘ S 22° 40 ‘ E), Botswana.
Distribution
»Okavango basin and upper Zambezi River«.