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 Neognathae Pycraft, 1900 see Cohort Neognathae Pycraft, 1900
                 Order Procellariiformes Fürbringer, 1888
                   1 Family Diomedeidae Gray, 1840 - albatrosses
                   2 Family Procellariidae Leach, 1820 - petrels, shearwaters
                   3 Family Pelecanoididae Gray, 1871 - diving petrels
                   4 Family Oceanitidae Forbes, 1882