COMPARATIVE-STUDY OF FOSSIL AND PRESENT P OPULATIONS OF MICROTUS (TERRICOLA) PYRENAICUS (RODENTIA, ARVICOLIDAE)

The comparative study of populations of Microtus (Terricola) pyrenaicu s, M. (T.) subterraneus and M. (T.) duodecimcostatus shows that the de ntal morphology (M1) of M. (T.) pyrenaicus is halfway between that of M. (T.) subterraneus and that of M. (T.) duodecimcostatus. Whatever th e type of analysis (discriminant or character analysis) no noticeable morphological differences are observed between the three listing subsp ecies described from the Pyrenees (pyrenaicus, planiceps) and the Gers country (brunneus). A gradual evolution may be hypothesized from M. ( T.) mariaclaudiae to M. (T.) pyrenaicus since the Middle Pleistocene.