In 1980, Argentinean zoologist Elio Massoia suggested that Winge's Hesperomys simplex and the living Pseudoryzomys wavrini are in fact the same species. In a 1991 study, American zoologists Voss and Myers confirmed this suggestion after re-examining Winge's material, finding no appreciable differences among specimens of H. simplex and P. wavrini.
In 1980, Argentinean zoologist Elio Massoia suggested that the species Hesperomys simplex (Winge) and Pseudoryzomys wavrini are the same. American zoologists Voss and Myers confirmed this in a 1991 study after re-examining Winge's material, finding no significant differences between specimens of H. simplex and P. wavrini.