Morphological differentiation of two marmot forms, Marmota baibacina and Marmota sibirica (Rodentia), in Southern Mongolia

摘要

A comparative analysis of Marmota baibacina and M. sibirica forms from Mongolia was performed on the basis of some dimensional and qualitative characters of their skull structure. Using methods of the cluster and discriminant analyses there were made classification of individuals in the aggregation of each form and classification of geographical samples. In the first case the inner structurization of variability, separately for baibacina and sibirica, was considered, in the second one a similarity of separate geographical samples was analyzed. These forms are shown to differ significantly both in dimensional and qualitative characters providing the impatibility to distinguish these two groups though not to determine their taxonomic position. The group centralis holds a separate position among baibacina; among sibirica only marmots from the Transbaikal region are distinguished. Other groups of marmots are unstable enough and should be investigated more extensively on the basis of geographical and morphological material. Hybridization between the forms at the contact zone leading to developing forms with intermediate characters was not observed.