The neotropical catfish genus Epapterus Cope (Siluriformes : Auchenipteridae): a reappraisal

The Neotropical auchenipterid catfish genus Epapterus Cope is reviewed. Epa pterus was found to share synapomorphies with Auchenipterus Valenciennes an d Pseudepapterus Steindachner and within that clade it is the sister-group to Pseudepapterus. Epapterus lacks an adipose dorsal fin, a derived reducti ve feature unique to the genus within the clade consisting of Epapterus, Au chenipterus, and Pseudepapterus and which is hypothesized to be a synapomor phy for the genus. The extension of the interradial membrane to join the co ntralateral pelvic fins is identified as an additional possible synapomorph y for Epapterus. Contrary to recent practice, Epapterus is considered to co nsist of only two species, E. dispilurus Cope (1878) and E, blohmi Vari et al. (1984). Examination of Epapterus samples from a number of localities in the Rio Amazonas and Rio Paraguay basins failed to reveal differences betw een the populations of the genus in those drainage systems. As a consequenc e Epapterus chaquensis Risso & Risso (1962), described from the Rio Paragua y system, is placed as a synonym of E. dispilurus originally described from the western portion of the Amazon basin. Euanemus longipinnis Steindachner (1881) is retained as a synonym of Epapterus dispilurus as proposed by Ste indachner (1882) and Eigenmann & Eigenmann (1888). Epapterus dispilurus is found to have a broad distribution in the central and western portions of t he Rio Amazonas system and the Rio Paraguay basin. The distribution of E. b lohmi is extended from the state of Guarico, Venezuela to include other por tions of the Rio Orinoco basin and the Rio Tuy of the Caribbean coast of Ve nezuela.