Revision of the Aragonian (Miocene) Atlantoxerus (Sciuridae)

Due to similarities in size as well as in morphology between the type materials of both species, synonymy of Atlantoxerus idubedensis Cuenca Bescos, 1988, with the species A. blacki (de Bruijn, 1967) is proposed. New and previously described material of the genus Atlantoxerus from the Aragonian type area in Spain are assigned to a single species, A. blacki, on the basis of metrical and morphological analyses. An emended diagnosis for A. blacki is proposed in order to include the observed variability. This species is characterized by its high morphological variability, tendency towards reduction in some relative dental proportions, and tending to increase in size rapidly.