Class [Mammalia] Linnaeus, 1758 - mammals
   Order Rodentia Bowdich, 1821 - rodents
     Family Muridae Batsch, 1788 - rats, mice, hamsters, voles, lemmings, and gerbils
       Subfamily Hesperomyinae Murray, 1866 - New-World mice and rats see Subfamily Sigmodontinae Wagner, 1843
         Genus Thomasomys Coues, 1884 - Thomas's paramo mice
           Thomasomys cinereiventer J. A. Allen, 1912