Dams Dams represent a risk to some species, but others may benefit from them. For example, the Guaíra Falls disappeared after the completion of the Itaipu Dam, allowing Potamotrygon amandae (formerly misidentified as P. motoro) and P. falkneri to spread into the upper Paraná basin. When the Tucuruí Dam was completed, there was an increase in potential prey animals, allowing the population of P. henlei to increase. In contrast, dams threaten some species such as P. magdalenae by isolating populations and preventing gene flow, and others such as P. brachyura generally avoid lentic habitats, including the reservoirs created by river impoundment. Fishing and capture In addition to the large numbers caught for food (hundred of tons per year in the Brazilian Amazon alone), many are killed because of the risk their stings represent to locals and tourists. In the Amazon, it has been estimated that many thousand river stingrays are removed from certain areas to minimize the risk to ecotourism. Such removal is unregulated by the authorities, as not considered fishing in the traditional sense. Initially Brazil completely banned all exports of wild-caught freshwater stingrays for the aquarium trade, but have since introduced quotas for some species. From 2010 to 2015, between 4,600 and 5,700 of six species (the vast majority were P. leopoldi and P. wallacei; the latter formerly referred to as P. cf. histrix) were legally exported from Brazil per year. The income generated from these are important to several small fishing communities. Other primary exporters of wild-caught freshwater stingrays are Colombia and Peru. A level of illegal exports also occur, and to curb this Paratrygon aiereba (in Colombia) and several Potamotrygon species (in Brazil and Colombia) have been included on CITES Appendix III. It has been suggested that all members of the family should be included on Appendix III, with Paratrygon and a few Potamotrygon species on Appendix II. Taxonomy and species The taxonomy of the river stingrays is complex and undescribed species remain. The two species of Styracura were only moved to this family in 2016. Among the freshwater species, Heliotrygon and Paratrygon are sister genera, and Plesiotrygon and Potamotrygon are sister genera. Subfamily Styracurinae Genus Styracura Carvalho, Loboda & da Silva, 2016 Styracura pacifica (Beebe & Tee-Van, 1941) (Pacific chupare) Styracura schmardae (Werner, 1904) (Chupare stingray) Subfamily Potamotrygoninae Genus Heliotrygon Carvalho & Lovejoy, 2011 Heliotrygon gomesi Carvalho & Lovejoy, 2011 (Gomes's round ray) Heliotrygon rosai