An individual of flying squirrel (Pteromys volans) belonging to the Far Eastern philogenetic lineage was found in the suburbs of Moscow.

TLDR: The southern border of the flying squirrel (Pteromys volans) natural range goes through the northern and eastern parts of the Moscow oblast as discussed by the authors, and there is a population formed by animals brought to the Zvenigorod Biological Station from other areas, including the Far Eastern part of the species range.

Abstract: The southern border of the flying squirrel (Pteromys volans) natural range goes through the northern and eastern parts of the Moscow oblast. However, near Zvenigorod (western part of the Moscow oblast), there is a population formed by animals brought to the Zvenigorod Biological Station of the Moscow State University from other areas, including the Far Eastern part of the species range. Since 2010, flying squirrels have been registered in the Troitsk district, southwest from the urban part of the city of Moscow. Genetic analysis of a dead animal found in this district showed a high similarity of the sequence of mtDNA fragment with sequences typical for the Russian Far East—but not for the European part of the species range. It is suggested that descendants of the Far Eastern flying squirrels unintentionally introduced near Zvenigorod are actively expanding their range throughout the Moscow oblast.