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