Vertebrata Cuvier, 1812 - vertebrates
   Gnathostomata
     Teleostomi
       Tetrapoda Hatschek & Cori 1896 [Gauthier, Kluge & Rowe 1988]
         Amniota Haeckel, 1866 [Gauthier, Kluge & Rowe 1988] - amniotes
           Class Aves Linnaeus, 1758 - birds see Subclass Aves Linnaeus, 1758
             Subclass Neornithes Gadow, 1893 see Clade Neornithes Gadow, 1893
               Superorder Palaeognathae Pycraft, 1900 see Cohort Palaeognathae Pycraft, 1900
                 1 Family †Lithornidae Carroll, 1988, nom. null. see Family Lithornithidae Houde, 1988
                 2 Order Tinamiformes Huxley, 1872 [monotypic]
                 3 Order Struthioniformes Latham, 1790 [monotypic]
                 4 Order Rheiformes Forbes, 1884 see Suborder Rheae Forbes, 1884
                 5 Order Casuariiformes Sclater, 1880
                 6 Order ‡Aepyornithiformes Newton, 1884 [monotypic]
                 7 Order ‡Dinornithiformes Gadow, 1893 [monotypic] - moas
                 8 Order Apterygiformes Haeckel, 1866 [monotypic]