What is "paratrygon"

Paratrygon is a monotypic genus of the cartilaginous fish in the family of Potamotrygonidae. The sole species is Paratrygon aiereba, the discus ray, which is native to South American rivers in the Amazon and Orinoco basins. The scientific name of the species was first validly published in 1841 by Müller & Henle.