Carvalho MR de, Ragno MP. An unusual, dwarf new species of Neotropical freshwater stingray, Plesiotrygon nana sp. nov., from the upper and mid Amazon basin: the second species of Plesiotrygon (Chondrichthyes: Potamotrygonidae) . Pap. Avulsos Zool. 2011;51(7):101-138. doi:10.1590/S0031-10492011000700001