Class Aves Linnaeus, 1758 - birds see Subclass Aves Linnaeus, 1758
   Subclass Ornithurae Haeckel, 1866 see Clade Ornithurae Haeckel 1866 [Gauthier 1986] {Chiappe 1991}
     Infraclass Carinatae Merrem, 1813 see Clade Carinatae Merrem 1813 [Gauthier & de Queiroz 2001]
       Order Gaviiformes Wetmore & Miller, 1926
         1 Family †Enaliornithidae Fürbringer
         2 Family †Lonchodytidae Brodkorb
         3 Family Gaviidae Allen, 1897 - divers