Holotype: UFRGS 19525. Paratypes: numerous.
Type locality: Brazil, Rio Grande do Sul State, Dois Lageados, rio Carreiro downstream to hydroeletric plant PCH Linha Emília, rio Taquari-Antas basin, rio Jacuí drainage, laguna dos Patos system, 28°56’30”S 51°46’30”W.
Etymology: The specific epithet bagual, from Tupi-Guarani, means wild horse, or what is mortal, or dangerous to mount. This expression is used mainly to convey the information that a given horse is a male reproductive in the countryside of Rio Grande do Sul State. The species is named in allusion to the presence in mature males of bony hooks on all fins.