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 Sciurinae Batsch, 1788 - tree and ground squirrels
           Genus Spermophilus Cuvier, 1825 - ground squirrels
             Spermophilus brunneus (A.H. Howell, 1928) - Idaho ground squirrel