Uncertainties in Systematics of Flying Squirrels (Pteromyini, Rodentia): Implications from a New Record from Vietnam

Taxonomic status of gliding squirrels belonging to the “northern” form of Petinomys setosus known from N. Burma and Thailand has been controversial. Earlier it was assigned to a distinct genus Olisthomys, however, currently it is synonymized with P. setosus s. str. from Sumatra and Borneo Islands, and Malay Peninsula. A squirrel collected in Song Hinh forest (Phu Yen Province, south central Vietnam) was examined genetically using sequence data on three mitochondrial genes (cytb, 12S, 16S) and one nuclear (IRBP) gene. The molecular results demonstrated that this squirrel is significantly divergent from the other examined specimens of Petinomys and belongs to a separate genetic lineage within the Glaucomyina clade. The obtained phylogenetic pattern supports recognition of Olisthomys as a valid genus; however, to confirm this conclusion a comprehensive taxonomic revision of Petinomys and related genera is required. The reconsideration of taxonomic position of the “northern” P. setosus also raises the question of the conservation status of this taxon.