Comparative karyology and craniology in birch mice of the group 'betulina' (Rodentia, Dipopoidea, Sicista) [Russian]

摘要

A comparative analysis of karyotypes, craniological and craniometric characteristics in birch mice of the group "betulina" (Sicista betulina, S. strandi, and S. pseudonapaea) was carried out for the first time. The karyotypes were investigated using methods of differential staining (G-, C-, and NOR-banding) of chromosomes. Variation of cranial characteristics was studied by phenetic and craniometric methods of multivariate (discriminatory and factor) analyses. The species specificity was revealed based on specific features of chromosomes and the data of the discriminatory analysis. Discriminatory equations make it possible to distinguish the species studied using 8 characters. The peculiar characteristics of the species under study exhibit a lack of congruence between the craniological, craniometric, and chromosomal data. In the group studied, S. pseudonapaea is the most distinctive species by its craniometric characteristics, and S. betulina, by chromosomal ones. This discrepancy indicates a "mosaic" pattern of evolution in birch mice of this group within the genus Sicista. The results of craniological and craniometric variability are discussed related to specific ecology of the studied species under changing environmental factors.