Class Mammalia Linnaeus, 1758 - mammals
   Order Rodentia Bowdich, 1821 - rodents
     Suborder Sciurognathi (Tullberg, 1899) see Suborder Sciuromorpha Brandt, 1855
       Family Muridae Batsch, 1788 - rats, mice, hamsters, voles, lemmings, and gerbils
         Subfamily Arvicolinae Gray, 1821 - voles
           Genus Synaptomys Baird, 1857 - bog lemmings
             1 Synaptomys borealis (Richardson, 1828) - northern bog lemming
             2 Synaptomys cooperi Baird, 1857 - southern bog lemming
             3 Subgenus Mictomys (True, 1894)
             4 Subgenus Synaptomys Baird, 1857