Evolutionary patterns of early and middle Aragonian (Miocene) of Megacricetodon (Rodentia, Mammmalia) from Spain

We have described the material of Megacricetodon from early to middle Aragonian from the Caltayud-Montalbán Basin. All studied assemblages are assigned to M. primitivus. The evolutionary patterns of this species are stable through time, in size and dental morphology, although with high intra-populational variability. We study a more abundant material of M. primitivus from its type locality, Valtorres, which shows strong taphonomical deformations that affect the metrical variability. We also discuss its biostratigraphic position proposing the correlation with Spanish local zone Da (middle Aragonian). Other Megacricetodon assemblages from Europe, previously assigned to M. primitivus, have been compared with the type material. The results of this comparison indicate that the geographical distribution of M. primitivus is restricted to Southwestern Europe, specifically the Iberian Peninsula and France.