Caballerotrema brasiliense Prudhoe, 1960 (Digenea: Caballerotrematidae). Scale value beside bars. Ventral views. A–C, C. brasiliense (voucher USNM 1717987) from the intestine of an arapaima, Arapaima gigas (Schinz) sensu lato (Osteoglossiformes: Arapaimidae) from the Amazon River near Leticia, Amazonas, Colombia. D–F, C. brasiliense (as C. piscicola; type series USNM 1339898) from the intestine of an arapaima from an unknown locality in the Amazon River, Brazil. A, Whole body. B, Head collar. C, Ventral lobes of head collar. D, Whole body. E, Head collar. F, Ventral lobes of head collar. Abbreviations: head collar projections (hcp); latero aboral (la); latero oral (lo); medio aboral (ma); medio oral (mo).