Abstract
Among the Elasmobranchs, the stingrays of the family Potamotrygonidae an important part of the Neotropical ichthyofauna, is the only group of elasmobranchs totally restricted to the freshwater environment. This family comprises 26 valid species, which are distributed in the genera Heliotrygon, Paratrygon, Plesiotrygon and Potamotrygon. Paraná River Basin, in the late 70s, the occurrence o…