Mayes, Brooks & Thorson 1981. Potamotrygonocotyle tsalickisi, new genus and species (Monogenea: Monocotylidae) and Paraheteronchocotyle amazonensis, new genus and species (Monogenea: Hexabothriidae) from Potamotrygon circularis Garman (Chondrichthyes: Potamotrygonidae) in northwestern Brazil. Proceedings of the Biological Society of Washington, 94(4) 1981: 1205-1210