Class [Mammalia] Linnaeus, 1758 - mammals
   Order Rodentia Bowdich, 1821 - rodents
     Family Sciuridae Batsch, 1788 - squirrels, chipmunks, marmots, and prairie dogs
       Subfamily Pteromyinae Brandt, 1855 - flying squirrels
         Genus Iomys Thomas, 1908 - Horsfield's flying squirrel
           Iomys horsfieldii Waterhouse, 1837[1838] - Horsfield's flying squirrel
           Iomys sipora Chasen & Kloss, 1927[1928]
           Iomys winstoni see Hylopetes winstoni Sody, 1949