Vertebrata Cuvier, 1812 - vertebrates
   Gnathostomata
     Teleostomi
       Tetrapoda Goodrich, 1930
         Amniota Haeckel, 1866 - amniotes
           Class Aves Linnaeus, 1758 - birds see Subclass Aves Linnaeus, 1758
             1 Subclass †Archaeornithes Gadow, 1893 [monotypic] see Superorder Archaeornithes Gadow, 1893
             2 Subclass Neornithes Gadow, 1893 see Clade Neornithes Gadow, 1893