Potamotrygon

They are native to the north, center, and east of South America, living in rivers that drain towards the Caribbean Sea, and towards the Atlantic Ocean, reaching the south to the Río de la Plata between Argentina and Uruguay. In general, each species is native to individual river basins. The greatest diversity of river stingray species is found in the Amazon basin, in Colombia they are found more in the Magnalena River.

River rays have an almost circular shape and vary in size from a diameter of a few decimeters to the short-tailed river ray, some of which can measure up to 2 meters in diameter. The upper surface is covered with denticles (scales with tooth-like tips). Most species are brown or grayish in color, and often have distinctive spotted or mottled patterns, but some species are mostly blackish with contrasting black spots.