Plesiotrygon is a genus of freshwater stingrays in the family Potamotrygonidae, native to the western Amazon basin - the brief's countries are Brazil, Colombia, Peru, and Ecuador. The atlas's 2 species range widely in size, from 6–23 in, and the genus's defining feature is an unusually long, slender, whip-like tail relative to its disc, which gives both species their common names: the antenna ray (Plesiotrygon iwamae) and the dwarf antenna ray (P. nana). Like other potamotrygonids, they are cartilaginous fish that are fully freshwater-adapted, with a flattened disc-shaped body, eyes and spiracles on top of the head, and a mouth on the underside suited to feeding on invertebrates and small prey in sand and mud substrates.
Freshwater stingrays as a group are viviparous, bearing live young nourished in the uterus, and carry a venomous serrated spine on the tail used purely in self-defence - a feature that makes careful handling essential wherever they are kept. Conservation status for this genus leans toward concern: one species is assessed as Vulnerable and the other Near Threatened, in line with the broader pressure freshwater stingrays face from habitat loss and collection across the Amazon basin.