Види та екоморфологічна диференціація роду Arvicola (Mammalia) у Східній Європі

Abstract

The genus Arvicola is represented in the fauna of Eastern Europe by several taxa and ecological races of semi-species and subspecies rank. Morphological data indicate the taxonomic homogeneity of lowland amphibious forms and a high level of differentiation of some mountain fossorial forms. Analysis of variation of morphometric characters shows a substantial hiatus for the Carpathian form of Arvicola, considered as A. scherman, as well as the absence of sufficient differentiation among other forms such as in lowland water voles from different parts of Ukraine or in mountain forms from the Northern Caucasus. Morphological features of the Carpathian taxon (A. scherman gutsulius) are stable compared to other mountain water vole populations from Europe and its substantial differences from the Caucasian form, which is very close to the lowland A. amphibius, do not support the idea of the ‘effect of mountains’ in the formation of small fossorial forms of Arvicola. The Carpathian Arvicola differs from all of the studied lowland forms in both morphometric and craniometric characters, which are important in the taxonomy and diagnostics of water voles (coefficient of divergence in body and skull dimensions reach CD = 4...5 ϭ. The mountain water vole (A. scherman) is characterized by a number of paedomorphic features that should be recognized as an ancestral state (plesiomorpy), whereas the European water vole (A. amphibius) is considered as an evolutionary advanced and gerontomorphic form. These two species are allopatric and the border between their distribution ranges coincide with the geographic limits of lowland and mountain faunal assemblages. Evidence for the recognition of the mountain fossorial form as either a separate species or an ecological race of the lowland species is considered. The fossorial A. scherman can be included to the group chosaricus–mosbachensis, but it remains unclear whether it should be considered an ancestral form in the evolution of the lowland A. amphibius or as an example of recapitulation of characters due to secondary transition to fossorial lifestyle. A comparison of different geographic forms of Arvicola suggests that the formation of the group took place in piedmont–mountainous areas of Europe, whereas the forms distributed further east are probably derived from the European ones.