Skull Sizes and Proportions in Western Palearctic Wood Mice (Sylvaemus, Muridae, Rodentia) from Eastern Europe: 2. Intraspecific Variability

Abstract

Intraspecific variability of craniometric characters (absolute measurements and indices) has been studied in the pygmy wood mouse Sylvaemus uralensis and the yellow-necked mouse S. flavicollis from a number of localities of Eastern Europe. A total of 478 skulls of Sylvaemus specimens were measured and analyzed. Cluster analysis of skull measurements showed that both S. uralensis and S. flavicollis could be split into two groups, the northern and the southern ones, which completely correspond to the genetically described intraspecific structure of S. flavicollis, but only partly in regards to S. uralensis. The northern and southern groups of both species are distinguished for the first time using discriminant analysis. Indices (relative skull measurements) related to the character of feeding are discussed. The intraspecific craniometric variability of S. flavicollis is suggested to be related to distinctions in the diet and the ways of getting food, whereas for S. uralensis no relation between the values of the indices of the dental apparatus and feeding features in different parts of its distribution range has been revealed.