[organisms] see Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
   Kingdom Animalia Linnaeus, 1758 - animals
     Branch Eumetazoa Butschli, 1910 see [unranked] Eumetazoa Bütschli, 1910
       Division Bilateria Hatschek, 1888 see Subkingdom Bilateria Hatschek, 1888
         Subdivision Deuterostomia Grobben, 1908 see Infrakingdom Deuterostomia Grobben, 1908
           Phylum Chordata Bateson, 1885 - chordates
             Subphylum Vertebrata Cuvier, 1812 - vertebrates
               Superclass Tetrapoda Goodrich, 1930 - tetrapods see Clade Tetrapoda Hatschek & Cori 1896 [Gauthier, Kluge & Rowe 1988]
                 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 Anseriformes Wagler, 1831 - waterfowl and screamers
                         Family Anatidae Vigors, 1825 - ducks, geese, swans
                           Genus Aythya Boie, 1822 - hardhead
                             Aythya americana (Eyton, 1838) - redhead
                             Aythya valisineria (Wilson, 1814) - canvasback