Heteromormyrus ansorgii (Boulenger, 1905)
Slender stonebasher
photo by Mertens, P.

Family:  Mormyridae (Elephantfishes)
Max. size:  15 cm SL (male/unsexed)
Environment:  demersal; freshwater
Distribution:  Africa: Cuanza River in Angola (Ref. 52193, 128501), also Cunene, Okavango, upper Zambezi, Buzi and Pungwe rivers, and an isolated population occurs in the Ruo River (lower Zambezi system) in Malawi (Ref. 52193). In the Congo basin known from the Kwango in Angola (Ref. 11970). Possibly also in the Inkisi River (lower Congo) (Ref. 12818, 120641), Lufira and Luwombwa rivers (upper Congo basin) (Ref. 12818) but these need confirmation.
Diagnosis:  Dorsal spines (total): -0; Dorsal soft rays (total): 18-19; Anal spines: -0; Anal soft rays: 24-26. Diagnosis: dorsal fin origin nearer caudal fin base than tip of snout; origin of dorsal fin behind origin of anal fin; dorsal fin shorter than anal fin; chin (mental swelling) present but feebly developed; dorsal fin with 19 rays, anal fin with 24-26 rays (Ref. 52193). Description: scales small; body long and slender, compressed; caudal fin forked, with rounded lobes; mouth small, with small mental lobe; 7-8 bicuspid teeth in both jaws (Ref. 52193). Coloration: usually dark brown or black (Ref. 52193), with vertical bar from dorsal origin (Ref. 52193) to anal fin in adults (Ref. 13337).
Biology:  Found in rocky habitats in flowing waters (Ref. 7248, 52193). Feeds on small aquatic invertebrates (Ref. 7248, 52193) such as insect larvae (Ref. 7248).
IUCN Red List Status: Least Concern (LC); Date assessed: 24 July 2018 Ref. (130435)
Threat to humans:  harmless


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