A new species of apteronotid electric fish is described from the Brazilian and Peruvian Amazon. Sternarchella calhamazon sp. n. conspicuously differs from its congeners in caudal peduncle shape, electric organ size and shape, hemal spine elongation above the anal fin, and arrangement of intermuscular bones adjacent to the electric organ. Sternarchella calhamazon is among the most common gymnotiform species living in the principal channels of the lowland Amazon River and its large tributaries.
The nominal apteronotid Sternarchus capanemae Steindachner is an earlier published, objective synonym of Sternarchella schotti Steindachner, both names appearing in 1868. Because S. capanemae was never used as a valid name after its first use, it should be considered a nomen oblitum and Sternarchella schotti should be considered a nomen protectum and the valid name of this species.
