Marcusenius cyprinoides (Linné, 1758)
Species overview
Larger species, variable in shape from rather deep to elongate, head uneven blunt-snouted,, chin with strong globular swelling caudal peduncle deep. Silvery, with blue or green shine, with darker back countershaded. Size observed: 330 mm SL, 458 g body weight.
M. cyprinoides(measurements)
Taxonomic description
-Body laterally compressed, deep or elongate, depending on geographical origin, body depth quite variable, 16-32 % SL, greatest depth above middle of trunk.
-Head slightly longer than deep, head length 18-25 % SL, head depth 13-21 % SL, 60-84 % body depth.
-Outline of back convex, upper profile of head convex, underside of head concave, outline of belly slightly convex.
-Snout obtusely pointed, short, 15-23 % head length, 26-37 % postorbital length.
-Mouth small, 10-22 % head length, terminal, its edge between nostrils, upper jaw on a level with lower rim of eye.
-Chin with strong globular swelling (in museum specimens often distorted.) Teeth small, conical, 5/4-6.
-Nostrils separate, circular, posterior nostril on a level with centre of eye, anterior nostril above it, axis of nostrils cuts axis of head at an angle of about 45°.
-Eye moderate, its diameter 10-18 % head length, 17-29 % postorbital length.
-Opercular cleft curved, 28-46 % head length, 40-56 % head depth.
-Dorsal fin 25-31 fin-rays, base of D 16-24 % SL, anal fin 30-37 rays, base of A 22-30 % SL, origin of D behind origin of A, end of D before end of A; predorsal length 55-64 % SL, preanal length 52-60 % SL.
-Pectoral fin pointed, reaching to base of pelvic fin . V is closer to P than to A.
-Caudal fin pointed, scaled lobes obtusely pointed, extending to 1/2 or 2/3 of its length. 70-86 scales in lateral line; 16 (rarely 18) scales round caudal peduncle.
-Caudal peduncle 12-22 % SL, its depth 6-8 % SL, 26 49 % its length.
-Coloration »Silvery, back darker, bluish or greenish; some young specimens with small blackish dots scattered on the body« (Boulenger, 1909a: 111); »Silvery-grey, sometimes dark grey, rather blackish«. (Bigorne, 1990: 141)
Type locality
Mormyrus cyprinoides: »Nilo«.
Mormyrus salahie: »Nil«.
Mormyrus labiatus: »Nil, (Egypte)«.
Mormyrus abbreviatus: »Egypte«.
Mormyrus elongatus: »?auf dem Markte von Cairo«.
Gnathonemus cyprinoides var. elongata: »Soueïram (Lac Tchad)«.
Distribution
Nile, from the Delta to Bahr-el Jebel, Niger and Chad basins; Ouellé river, Zaïre (between 3-4°N and 28-29°E)