BIOGEOGRAPHY AND TAXONOMY OF APODEMUS-SYLVATICUS (THE WOODMOUSE) IN THE TYRRHENIAN REGION - ENZYMATIC VARIATIONS AND MITOCHONDRIAL-DNA RESTRICTION PATTERN-ANALYSIS

In the western Mediterranean area, the taxonomic status of the various forms of Apodemus sylvaticus is quite unclear. Moreover, though anthr opogenic, the origins of the island populations remain unknown in geog raphical terms. In order to examine the level of genetic relatedness o f insular and continental woodmice, 258 animals were caught in 24 loca lities distributed in Belgium, France, mainland Italy, Sardinia, Corsi ca and Elba. Electrophoresis of 33 allozymes and mtDNA restriction fra gments were performed and a UPGMA dendrogram built from the indices of genetic divergence. The dendrogram based on restriction patterns show s two main groups: 'Tyrrhenian', comprising all the Italian and Corsic an animals and 'North-western', corresponding to all the other mice tr apped from the Pyrenees to Belgium. Since all the Tyrrhenian mice are similar and well isolated from their relatives living on the western e dge of the Alpine chain, they must share a common origin. The insular populations are consequently derived from peninsular Italian ones. Fro m a taxonomic point of view and taking the priority rules into account , we have to invalidate A. s. clanceyi Harrison, 1948 and to consider the Tyrrhenian woodmice as belonging to A. s. milleri de Beaux, 1926, whereas the North-western ones must be referred to as the nominal subs pecies. As far as the Elban woodmouse is concerned, at the moment we p refer to keep its present subspecific status because we only studied o ne animal.