Mediterranean small mammals and insular syndrome: biometrical study of the long tailes field mouse (Apodemus sylavticus) (Rodentia Muridae) of Corsica

The presence in Corsica of a field mouse is well known. Several authors have noted some of its morphological peculiarities but it was only recently (1980) that the presence of A. sylvaticus was establblished with certainty. However, this evidence is based on a check of a limited number of individuals originating from a single locality. In order to generalize these observations, we performed o biochemical test on six Corsican mice caught in three distinct localites and a morpho biometrical study of 491 skulls. The results show that A. sylvaticus is spread all over the island and that A. flavicollis is probably absent. No sexual dimorphism was found but strong spatial variations in the cranial measurements were ividenced. There are far less important between the various Corsican sub samples than between the insular and the continenecal mice. The evolutionary and adaptive significance of the increase in size of insular mice is discussed in relation to the theory of island biogeography and to the present knowledge on the history of the mammalian settlement of the island.