living organisms see Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
   Superkingdom Eukaryotae see Domain Eukaryota Chatton, 1925
     Kingdom Animalia Linnaeus, 1758 - animals
       Subkingdom Eumetazoa Butschli, 1910 see [unranked] Eumetazoa Bütschli, 1910
         Phylum Chordata Bateson, 1885 - chordates
           Subphylum Vertebrata Cuvier, 1812 - vertebrates
             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 Order †Diornithiformes see Order Dinornithiformes Gadow, 1893
                   2 Family †Aepyornithidae Bonaparte, 1853 - elephant birds
                   3 Family †Dromornithidae Vigors, 1825 - mihirungs
                   4 Order Struthioniformes Latham, 1790
                   5 Order Rheiformes Forbes, 1884 see Suborder Rheae Forbes, 1884
                   6 Order Casuariiformes Sclater, 1880
                   7 Order Apterygiformes Haeckel, 1866
                   8 Order Tinamiformes Huxley, 1872