Proechimys iheringi Thomas is an echimyid rodent occurring in eastern Brazil from the states of Bahia to Sao Paulo. MOOJEN (1948) recognized six subspecies of P. iheringi primarily on the basis of clinal variation in the number of cheekteeth counterfolds. In this study we analyzed infraspecific differentiation in 13 morphometric cranial characters in three populations assignable to three subspecies of P. iheringi. Cranial dimensions vary clinally increasing from north to south and morphometric differentiation is correlated with geographic distance. The congruence between the clinal variation in cheekteeth counterfolds and cranial traits indicates that the trinomial nomenclature should not be applied to P. iheringi.561344
