Gymnotus ucamara: a new species of Neotropical electric fish from the Peruvian Amazon (Ostariophysi: Gymnotidae), with notes on ecology and electric organ discharges

Abstract

A new species of Neotropical electric fish, Gymnotus ucamara, is described from floodplain habitats in the Rio Ucayali Basin, Peru. The new species is distinguishable from all congeners by the following combination of characters: a clear patch at the caudal end of the anal fin; two laterosensory canal pores (from the preopercular-mandibular series) in the dorso-posterior portion of the preopercle; a coloration pattern with 18–24 dark brown bands separated by narrow pale interbands which are less than one-third the width of the dark bands; a long head (12.2–13.4 % total length); many (10–11) scales rows over the anal fin pterygiophores; few (38-43) pored lateral-line scales to the first lateral-line ramus; and a low (75–91) total number of pored lateral-line scales.