Class Aves Linnaeus, 1758 - birds see Subclass Aves Linnaeus, 1758
   Subclass †Sauriurae Haeckel, 1866 see Subclass Archaeornithes Gadow, 1893
     1 Infraclass †Archaeornithes Gadow, 1893
     2 Infraclass †Enantiornithes Walker, 1981