Snow voles, genus Chionomys, of Turkey

Three species of snow vole are known from Turkey. The true snow vole, Chion omys nivalis, has been recorded from 20 localities and is widespread in Ana tolia. However, Robert's vole, C. roberti, and the Gudaur vole, C.gud, are restricted to the eastern Pontic Mts. where they are known from 11 and 4 lo calities, respectively. It is suggested that snow vole distributions were s haped by the degree to which individual species are associated with rocky e nvironments (nivalis congruent to gud > roberti) and by their dependence on mesic conditions (roberti > gud > nivalis). Robert's vole is the most dist inct in both morphology and habitat selection. The snow vole and Gudaur vol e are sympatric at three localities, although the former populates dryer ha bitats. These species are well differentiated morphologically, the snow vol e having a deeper skull and larger bullae; when in sympatry, the tail of th e Gudar vole is longer. No interpopulation variation was observed in extern al and cranial characters in Robert's and Gudaur voles. On the other hand, the true snow vole is highly variable, although the pattern of geographic v ariation found in dental characters does not correspond with that derived f rom cranial data.