Ocellate River Stingray - Potamotrygon motoro Potamotrygon motor (Rajiformes - Potamotrygonidae) is a species of freshwater stingray endemic to, and widespread throughout, several South American river systems. These stingrays can be distinguished from closely related species by the presence of orange to yellow dorsal eyespots, each surrounded by a black ring, with diameters larger than the eyes. Body color is otherwise greyish-brown. They are oval in shape with a robust tail, bearing a ...