Assessment differentiation degree cryptic species of the genus Apodemus in the Northern Caucasus based on non-metric cranial characters

A phenetic analysis of non-metric cranial traits of two genetically identified cryptic species of the genus Apodemus in different ecological conditions of the North Caucasus was carried out. The maximum distance obtained between cryptic species did not exceed the level of subspecies differences. The phenetic distance between A. uralensis and A. flavicollis, which inhabit symbiotopically and sympatrically in the Western Caucasus, is almost 2 times lower. The smaller value of phenetic differences is probably related to the habitat of both species in similar land-scapebiotopic and climatic conditions, which contributes to the development of phenotypic similarity. In general, the obtained results indicate weak morphological differentiation of the studied species according to the studied phenetic characters (cranial foramen), although according to the results of molecular genetic analysis of the cyt b gene site, the genetic distance between the studied taxa is 10% and corresponds to the level of interspecific differences. Based on the above, reliable diagnosis of the studied species in the Caucasus is possible only by molecular genetic methods