Biochronology, paleobiogeography and faunal turnover in western Mediterranean Cenozoic mammals.

Cenozoic terrestrial mammals from Sardinia contribute substantial information for reconstructing the complex history of the western Mediterranean. The occurrence of endemic perissodactyls in Eocene marine and marsh deposits suggests the existence of ecological or physical barriers between the Corso-Sardinian massif and the Iberian-Occitanic area. At the end of the Oligocene, isolation of Sardinia was almost complete, although a migration from Europe occurred at the beginning of the Early Miocene, as indicated by the unbalanced endemic fauna from Oschiri. During the Late Miocene, the Tusco-Sardinian palaeobioprovince came into existence as an isolated region inhabited by the quite diversified, but notably endemic, Oreopithecus fauna. Sardinia was definitely isolated from Tuscany by the Messinian, but temporary connections with the European mainland possibly allowed the colonization of forerunners of some Sardinian Pliocene taxa. During the Plio-Pleistocene, Sardinia maintained permanent isolation. However, sea level drop, resulting in a relatively short distance between Sardinia and the European mainland, allowed different migratory events. From the Late Pliocene to the Late Pleistocene-Holocene, two main mammalian faunal complexes (FC) can be recognized: the Nesogoral FC (Late Pliocene-Early Pleistocene) and the Microtus (Tyrrhenicola) FC (late Early Pleistocene-Early Holocene). At the transition from Nesogoral to Microtus (Tyrrhenicola) FC, approximately 47% of the genera and 76% of the species disappeared, while approximately 58% of the genera and 71% of the species appeared. A noticeable turnover followed the arrival of Neolithic man and his accompanying fauna. Nonetheless, Praemegaceros was still present at about 7000 years BP, while Microtus (Tyrrhenicola) and Prolagus are respectively recorded in the Bronze and Iron Ages.