Mormyrops (Mormyrops) anguilloides (Linné, 1758)
Species overview
Large fish, body elongate, low, moderately compressed, outlines straight, head moderately tapering, snout blunt, rounded, depressed and quite variable in shape; dorsal considerably shorter than anal, pectoral and caudal rounded; dark coloured. Size observed: 1500 mm TL.
M. anguilloides(measurements)1
M. anguilloides(measurements)2
Taxonomic description
-Body elongate, rather low, cross section rather oval, body depth 13-22 % SL, greatest depth usually near middle of body.
-Head length 22-32 % SL, head depth 13-17 % SL, 74-96 % body depth.
-Outline of back straight or feebly concave, upper profile of head as well as underside of head concave; outline of belly more or less straight.
-Snout long, tapering, depressed, rounded, slightly or not protruding mouth, its tip much less deep than head depth, 18-30 % head length, 25-34 % postorbital length.
-Mouth 13-21 % head length, slightly subterminal, its edge reaching to a level between the nostrils, upper jaw on a level with lower edge base of pectoral fin.
-Chin with moderate submental swelling, lower jaw less deep than upper part of snout.
-Teeth notched, 16-30/14-29, in closed rows (horse-like dentition), actual number depending on age / size.
-Nostrils separate much closer together than to rim of eye, anterior nostril circular, on a level with centre of eye, posterior nostril oval, on a level with lower rim of eye. Axis of nostrils cutting axis of head at an angle of lessrthan 30°.
-Eye diameter 5-13 % head length, 7-19 % postorbital length.
-Opercular cleft curved, 20-33 % head length, 39-70 % head depth.
-Dorsal fin 23-33 fin-rays, base of D 12-21 % SL, anal fin 36-50 rays, base of A 27-33 % SL, origin of D behind origin of A, end of D before end of A; predorsal length 66-72 % SL, preanal length 57-63 % SL.
-Pectoral fin rounded, not reaching to base of pelvic fin. V is slightly closer to P than to A.
-Caudal fin rounded, both membranous and scaled lobes, the latter covering 2/3 of the fin. 71-100 scales in lateral line; 12-22 round caudal peduncle.
-Caudal peduncle 9-14 % SL, its depth 3-6 % SL, 33-50 % its length).
-Coloration »Brownish or olive above, silvery beneath; - Uniform dark with brighter belly; - Olive or greyish brown above, witish beneath, sometimes end of snout much less deep than head depth dotted all over with black«. (Countershaded).
Type locality
M. anguilloides: »Nilo«
M. a. voltae: »Riv. Kou, affl. de la Volta Noire, Rép. Haute Volta«
M. dendera: »Nil« Dandara, Egypt (26° 10 ‘ N 32° 39 ‘ E)
M. herse: »Egypt« »Dongola in Nilo« Sudan (19° 10 ‘ N 30° 29 ‘ E)
M. curviceps: »Riv. Bougouriba, affluent de la Volta noire, près de Daragré«
M. deliciosus: »Congo River«
M. swanenburgi: »Kinshasa, Stanley Pool« Pool Malebo, Democratic Republic of Congo..
M. zambanenje: »Zambese«
M. longiceps: »Bossumprah River, Gold coast« Ghana.
Distribution
Lower and Upper White Nile, Lake Albert (Lake Mobutu) basin, Senegal, Gambia, -+*Niger, Chad, Volta, Congo and Zambesi basins, Lakes Malawi and Tanganyika; Whebi Shebeli and Juba, Somalia.
Electric organ discharges
M. anguilloides(EOD)
Remark
The various synonymous taxa are based on differences in proportions and meristics actually due to geographic gradients and with it hydrographic conditions.