WHAT COULD CAENOZOIC AND QUATERNARY TERRESTRIAL MAMMALS FROM SARDINIA TELL US ABOUT THE PALAEGEOGRAPHY OF THE WESTERN MEDITERRANEAN?

The Cenozoic and Quaternary terrestrial mammals from Sardinia contribute substantial information for reconstructing the complex and still controversial history of the evolution of western Mediterranean paleogeography. The occurrence of endemic perissodactyls in Eocene marine and mash deposits of Sulcis area, for example, suggests the existence of ecological or physical barriers between Sardinia and the Cantabric plus Provenzal regions. At the end of Oligocene isolation was complete, though a migration from Europe occurred at the beginning of Early Miocene, as indicated by the unbalanced endemic fauna from Oschiri.

During Late Miocene the Tusco-Sardinian paleobioprovince came into existence as an isolated region inhabited by the quite diversified, but notably endemic “Oreopithecus” fauna. The connection between Sardinia and Tuscany was active during the MN 12 as suggested by the occurrence of Eumaicherus and Agriotherium in both the Fiume Santo (Sardinia) and the Baccinello V2 (Tuscany) deposits. Sardinia was definitely isolated from Tuscany before the Messinian, since new immigrants from Europe have been thus far NOT been found in Sardinia. However, the possibility that some species, such as the ancestor of the Balearic and Sardinian bovids, migrated to Sardinia during the Messinian cannot be ruled out. Bovids have been found in the Mandriola and Capo Mannu faunas, ranging in age from Early to Late Pliocene, as well as in the karstic fissure of Monte Tuttavista. In the latter, the occurrence of the running predator, Chasmaportetes, forces reconsideration of Pliocene biogeography of the western Mediterranean. During the Pleistocene Sardinia maintained permanent isolation; however sea level drop and temporary emergence of marginal lands allowed different phases of migration of new taxa. At any rate, the renewed Sardinian fauna became more and more unbalanced as documented by a drop in diversity from the Pliocene-Early Pleistocene “Chasmaporthetes- Bovids” fauna to the Middle and Late Pleistocene “Tyrrhenicola- Praemegaceros” fauna.