Phylum Chordata Bateson, 1885 - chordates
   Class Aves Linnaeus, 1758 - birds see Subclass Aves Linnaeus, 1758
     Subclass Neornithes Gadow, 1893 see Clade Neornithes Gadow, 1893
       Superorder Neognathae Pycraft, 1900 see Cohort Neognathae Pycraft, 1900
         Order Galliformes Temminck, 1820 - fowl
           Family Tetraonidae Vigors, 1825
             1 Genus Dendragapus Elliot, 1864
             2 Genus Lagopus Brisson, 1760 - ptarmigan
             3 Genus Tetrao Linnaeus, 1758
             4 Genus Bonasa Stephens, 1819
             5 Genus Centrocercus Swainson, 1832
             6 Genus Tympanuchus Gloger, 1841