Rhagapodemus azzarolii n. sp. (Muridae, Rodentia) from the Pliocene of Mandriola (western Sardinia-Italy)

In this paper a study of the fossil remains of a murid of the genus Rhagapodemus found in the gisement of Mandriola (Sinis Peninsula, Western Sardinia - Italy) is made. This form was formerly considered as a subspecies of R. hautimagnensis, a Ruscinian species of mainland Europe. More detailed studies demonstrate that the Mandriola Rhagapodemus is a new endemic Sardinia species, to be named Rhagapodemus azzarolii. The continental ancestor of R. azzarolii has to be sought in R. ballesioi, another Ruscinian species of Western and Central Europe (MN14-MN15). This evidence, the slight, incipient endemic modifications of the dental patterns of the Mandriola population, and further studies on other small mammal taxa present in the gisement, imply the possibility of a faunal migration from mainland Europe to Sardinia during the Zanclean - Piacentian boundary. In Sardinia, the new species gave rise to an endemic evolutionary lineage that ends in the Middle/Late Pleistocene with Rhagamys orthodon.