A new species of electric knifefish from the rio Negro, Amazon basin (Gymnotiformes: Hypopomidae, Microsternarchini)

ABSTRACT. A new species of electric knifefish of the genus Microsternarchus is described from the central basin of the rio Negro, Brazil. The new species is distinguished in external features from its single congener, Microsternarchus bilineatus, by the presence of a short caudal filament, a lower number of anal-fin rays, and uniform body pigmentation. Internally, features of the skeleton also distinguish the two species, in particular in the shape of the maxilla and antorbital.