Phylogenetic relationships among six flying squirrel genera, inferred frommitochondrial cytochrome b gene sequences

Petauristinae (flying squirrels) consists of 44 extant species in 14 recent genera, and their phylogenetic relationships and taxonomy are unsettled qu estions. We analyzed partial mitochondrial cytochrome b gene sequences (1,0 68 base pairs) to investigate the phylogenetic relationships among six flyi ng squirrel genera (Belomys, Hylopetes, Petaurista, Petinomys, and Pteromys from Asia and Glaucomys from North America). Molecular phylogenetic trees, constructed by neighbor-joining and maximum likelihood methods, strongly i ndicated the closer relationship between Hylopetes and Petinomys with 100% bootstrap values. Belomys early split from other flying squirrels. Petauris ta was closely related to Pteromys, and Glaucomys was most closely related to the cluster consisting of Hylopetes and Petinomys. The bootstrap values supporting branching at the deeper nodes were not always so high, suggestin g the early radiation in the evolution of flying squirrels.