A taxonomic review of the Neotropical electric fish Rhamphichthys (Gymnotiformes: Rhamphichthyidae)

The species diversity and taxonomy of Rhamphichthys is reviewed and seven species are considered valid: Rhamphichthys apurensis from the Orinoco and Cuyuni river basins; R. drepanium from the Amazon and Orinoco river basins; R. hahni from the Paraná-Paraguay River system; R. heleios and R. lineatus from the Amazon River basin; R. pantherinus from the upper Orinoco, Essequibo, Amazon and coastal rivers of North Brazil, and R. rostratus from the upper Orinoco, Amazon and coastal rivers of Guianas. Based on the examination of specimens from nominal species, from across their geographic ranges, including specimen types, the previous synonymization of four species ( R. blochii, R. reinhardti, R. schomburgki, and R. schneideri) with R. rostratus, and R. marmoratus with R. pantherinus is confirmed. Two other nominal species, R. atlanticus and R. longior, are proposed as junior synonyms of R. pantherinus. Species are redescribed and diagnosed based on color pattern, morphometric, meristic, and internal anatomy characters. Distribution maps and an identification key based on the examination of a comprehensive list of materials are also provided.