Vertebrata Cuvier, 1812 - vertebrates
Gnathostomata
Teleostomi
Tetrapoda Hatschek & Cori 1896 [Gauthier, Kluge & Rowe 1988]
Amniota Haeckel, 1866 [Gauthier, Kluge & Rowe 1988] - amniotes
Class Aves Linnaeus, 1758 - birds
see Subclass Aves Linnaeus, 1758
Subclass Neornithes Gadow, 1893
see Clade Neornithes Gadow, 1893
Superorder †Odontognathae Wetmore, 1930
see Subclass Archaeornithes Gadow, 1893
Order †Hesperornithiformes Fürbringer, 1888
1 Family †Enaliornithidae Fürbringer
2 Family †Baptornithidae American Ornithologists' Union
3 Family †Hesperornithidae Marsh, 1872