Subclass Avialae Gauthier, 1986 see Clade Avialae Gauthier 1986
   Infraclass Aves Linnaeus, 1758 see Subclass Aves Linnaeus, 1758
     1 Parvclass †Palaeoaves Livezey & Zusi, 2007 see Class Aves Linnaeus, 1758
     2 Parvclass †Ornithurae Haeckel, 1866 see Clade Ornithurae Haeckel 1866 [Gauthier 1986] {Chiappe 1991}
     3 Parvclass †Eoaves Sibley et al., 1988 see Cohort Palaeognathae Pycraft, 1900
     4 Parvclass Neornithes Gadow, 1893 see Subclass Neornithes Gadow, 1893