Class Aves Linnaeus, 1758 - birds see Subclass Aves Linnaeus, 1758
   Subclass Ornithurae Haeckel, 1866 see Clade Ornithurae Haeckel 1866 [Gauthier 1986] {Chiappe 1991}
     1 Infraclass Dromaeognathae (Huxley, 1867) P. Brodkorb, 1963
     2 Infraclass Ratitae (Merrem, 1813) P. Brodkorb, 1963 see Parvclass Ratitae (Merrem, 1813)
     3 Infraclass Carinatae Merrem, 1813 see Clade Carinatae Merrem 1813 [Gauthier & de Queiroz 2001]