Variação morfológica de populações de Exodon paradoxus Müller & Troschel, 1844 (Characiformes: Characidae)

Abstract

Exodon paradoxus is a small-sized neotropical fish species that occurs in the Amazon and Tocantins-Araguaia basins. Considering the wide distribution of the species, the objective of the present work was to verify the taxonomic situation of the Exodon paradoxus through analyzes of the morphological, meristic and osteological characters of populations from the Branco river and the Tocantins-Araguaia river. Distance between spots was a morphological characteristic that showed variation between populations, along with variations in pectoral fin length and head length. Although there was an overlap between populations in counting the number of perforated lateral line scales and number of branched anal fin rays, there are trends to be verified. 33 vertebrae were counted in all diaphanized specimens. The dentition observed in these specimens did not show differences between the populations analyzed. After morphological, meristic and osteological analyzes among populations of Exodon paradoxus, it can be seen that there are variations that may corroborate the existence of new species, but it is necessary to increase the sample size to clarify their diagnosis. Keywords: piaba, taxonomy, characidae