Original investigationCranial variation and taxonomic content of the marbled polecat Vormela peregusna (Mustelidae, Carnivora)

Morphometric variation in 26 characters of 245 skulls of the marbled polecat (Vormela peregusna) was studied across the distribution range. Morphological diversity was low with respect to both the size and the shape of the skull. The sexual size dimorphism of cranial characters in V. peregusna was low compared with other similar-sized mustelids. This finding may be a result of more specialized behaviour, resulting in less intra-specific competition with respect to habitat and food selection. Analysis of the geographic variation of skulls revealed two morphological groups - western and eastern. These groups were treated as distinct subspecies in this study. Nominotypical V. p. peregusna (Güldenstädt, 1770) (syn. sarmatica, euxina) is found in southern and eastern Europe, Asia Minor and Caucasus. The eastern subspecies V. p. koshewnikowi Satunin, 1910 (syn. alpherakii, chinensis, negans, obscura, ornata, pallidior, syriaca, and tedshenika) is found south and east of the Middle East, in Middle and Central Asia and eastward to China. Our data revealed a gradual decrease in the morphological diversity in Vormela skulls from west to east in the distribution range. This phenomenon may be explained by the later origin of the eastern subclusters of the marbled polecat. The pattern of geographic variation revealed in this study may reflect the Pleistocene history of the species range formation, rather than a relationship to climate conditions throughout the modern species range.