Akodontini. Diagnosed as a third genus of scapteromyines, along with Kunsia and Scapteromys (see Hershkovitz, 1966c), and so maintained by Reig (1980, 1981, 1984, 1986). More closely related to Akodon and kin than to Kunsia Scapteromys according to parsimony distillations of cytochrome b sequence data (D’Elía et al., in press). In analyses of mitochondrial and nuclear genes, D’Elía (2003) recognized Bibimys as one of five major clades within Akodontini.

Generic diagnosis emended, alpha taxonomy reviewed, and known fossil and recent occurrences consolidated by D’Elía et al. (in press). They provisionally retained three species, given the inadequacies of sample size and geographic representation, but acknowledged that morphological, karyotypic, and genetic evidence for their separation is unpersuasive. Karyology reported by Dyzenchauz and Massarini (1999) and Gonçalves et al. (in press). Fossil records (early Pleistocene to Holocene) of Argentina and Brazil summarized by Pardiñas (1996), who recharacterized the dental characteristics of the genus and compared them with Kunsia and Scapteromys.