Rodents from Botardo-D and the Miocene-Pliocene transition in the Guadix-Baza Basin (Granada, Spain)

Abstract

The rich small-mammal record from the Guadix-Baza Basin (Granada, southern Spain) provides a rather continuous biostratigraphic sequence from the late Miocene to the middle Pleistocene. However, the earliest Pliocene is not so well represented due to the scarcity of levels from this time. In this paper, a complete taxonomic study of the rodent fauna from Botardo-D is presented, providing a more complete information on this poorly known time interval. Representatives of the genera Stephanomys, Paraethomys, Apodemus, Castillomys, Debruijnimys and Apocricetus have been identified. The association indicates an intermediate biostratigraphic position between the levels of Negratín-1 (late Turolian, MN13) and Baza-1 (early Ruscinian, MN14), being now one of the oldest Pliocene sites in the Guadix-Baza Basin. Thereby, Botardo-D enhances our knowledge on the evolution of the rodent community recorded in this basin from the late Miocene to the early Pliocene. A qualitative palaeoecological interpretation suggests the dominance of open grasslands under relatively warm and dry climate conditions in the Guadix-Baza Basin during the deposition of Botardo-D. A tendency towards an increase in humidity from the Messinian Salinity Crisis (latest Miocene) to the Zanclean (early Pliocene) could be shown for southern Iberian Peninsula, supporting previous results.