Heliotrygon is a genus of freshwater stingrays in the family Potamotrygonidae, found in the deep river channels of the Amazon basin in Brazil and Peru. Its species stand apart from most other Potamotrygonidae by disc shape alone: an almost perfectly circular, flattened 'pancake' body with little or no externally visible tail spine, an adaptation to a life spent well below the shallow sandy margins that shallow-water ray genera prefer. Heliotrygon gomesi and Heliotrygon rosai range from around 12–31.5 in across, and both were only formally described in the last couple of decades, a reminder of how little-studied the deep river channels of the western Amazon remain.
Because they live in deep water rather than the accessible shallows worked by ray collectors, Heliotrygon species have essentially no established presence in the aquarium trade, unlike some of the more familiar shallow-water Potamotrygon rays. Both species are currently assessed Vulnerable, a status that reflects the general pressures facing Amazonian freshwater stingrays - habitat disturbance, incidental bycatch, and collection for the ornamental ray trade - layered onto the genus's naturally restricted, poorly surveyed range.