AbstractDespite obvious advances in systematic research on Palaearctic white-toothed shrews ( Crocidura ), phylogenetic relationships and species diagnosis of 40-chromosome species ( suaveolens sp. group) remain poorly understood. Phylogenetic relationships of these shrews were analyzed on the basis of two independent molecular markers: interspersed repeat PCR fingerprints (inter-SINE-PCR) and complete (1140 bp) or partial (∼400 bp) sequences of the mtDNA cyt b gene. According to these data, C.

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... suaveolens from Western Europe (Italy) appeared distinct from samples of C. suaveolens from Eastern Europe and Mongolia, as well as a Siberian sample. mtDNA introgression of Eastern European C. suaveolens with C. gueldenstaedtii in their contact zone in the Tuapse region was revealed. Hybrydization between C. gueldenstaedtii and C. suaveolens resulted in the formation of a population, nuclear DNA and morphological characteristics typical for C. gueldenstaedtii , while the mitochondrial genome is assimilated from C. suaveolens . The population of the Talysh region of the Caucasus ( C. caspica ) represents a separate entity that is clearly distinguished from the populations of Georgia and Tuapse ( C. gueldenstaedtii ) and C. suaveolens . Therefore, the position of C. caspica as a full species is supported. The present analysis of both inter-SINE-PCR and cyt b sequence data revealed two major clades in Palaearctic 40-chromosome Crocidura . The eastern clade is formed by true C. suaveolens/C. sibirica , together with C. caspica , and the western clade is formed by Western European C. suaveolens , which should be treated as a distinct species, C. mimula and the closely related C. gueldenstaedtii.