Kingdom [Animalia] Linnaeus, 1758 - animals
   Subkingdom Metazoa Haeckel, 1874 see Kingdom Animalia Linnaeus, 1758
     Division Eumetazoa Butschli, 1910 see Subkingdom Eumetazoa Butschli, 1910
       Subdivision Bilateralia
         Phylum Chordata Bateson, 1885 - chordates
           Subphylum Vertebrata Cuvier, 1812 - vertebrates
             Class Aves Linnaeus, 1758 - birds see Subclass Aves Linnaeus, 1758
               Subclass Neornithes Gadow, 1893 see Clade Neornithes Gadow, 1893
                 Order Charadriiformes Huxley, 1867 - shorebirds, gulls, auks
                   Suborder Lari Sharpe, 1891 - gulls and allies
                     Family Sternidae Bonaparte, 1838 see Subfamily Sterninae Bonaparte, 1838
                       Genus Hydroprogne Kaup, 1829 see Genus Sterna Linnaeus, 1758
                         1 Hydroprogne caspia (Pallas, 1770) see Sterna caspia Pallas, 1770