EN
The examination of dental morphology of coexisting modern Aethomys namaquensis Smith, 1834 and A. chrysophilus de Winton, 1896 from Mozambique, whose diet has been studied in the field, shows that the development of stephanodont crests and the multiplication of supplementary cusps on labial side of the lower molars is associated with a mainly vegetarian diet. To the most specialized dentition corresponds the most specialized diet. The application of these results to two coexisting Aethomys species from the fossil site of Langebaanweg (Pliocene, South Africa) allows to conclude that their dental differences correspond to different paieodiets. Moerover, the A. namaquensis lineage shows during Plio- Pleistocene times a shift in dental morphology corresponding to an evolution toward a more vegetarian diet. The comparative tooth anatomy seems to be a reliable method for determining diet of extinct rodents species, their close or less close relatives, when diets of extant species are precisely known.