Variação da nadadeira adiposa e nova ocorrência de Hasemania nana (Lütken, 1875) (Characiformes, Characidae) no alto rio Paraná

Abstract

Hasemania Ellis is one of the genera of Characidae diagnosed by the absence of an adipose fin, besides other combined characters. In the nine valid species, all them do not have an adipose fin, except for the "piabinha-vermelha" Hasemania nana described from the rio São Francisco basin. The record of populations of one characid with an adipose fin in the upper rio Paraná River basin, but with characters very close to Hasemania nana, were analyzed. The results showed great overlapping among the morphological characters of the populations from the upper Paraná River basin with Hasemania nana from the rio São Francisco basin, recording the first time the species for the upper rio Paraná basin. The polymorphism of the adipose fin found in both populations is discussed.