A review of the original descriptions and available types of the South American freshwater stingrays Trygon aiereba Müller & Henle, 1841, Trygon strogylopterus Schomburgk, 1843 and Disceus thayeri Garman, 1913 indicates that these three nominal species are synonymous. The senior name, placed in the monotypic genus Paratrygon Duméril, 1865, established for Trygon aiereba, is available and valid. Based on its description, T. aiereba is a freshwater stingray. Therefore, this taxon is not the same as Raja ajereba Walbaum and Raja orbicularis Schneider, both names established for the marine "Aiereba" of Marcgrave, and which preferably should be treated as nomina dubia. Paratrygon does not replace Potamotrygon Garman, 1877 as the type genus, because the family name Potamotrygonidae Garman, 1877 has priority over Paratrygonidade Gill, 1893.