Class Mammalia Linnaeus, 1758 - mammals
   Order Rodentia Bowdich, 1821 - rodents
     Suborder Sciurognathi (Tullberg, 1899) see Suborder Sciuromorpha Brandt, 1855
       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