[organisms] see Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
   Eukaryotes see Domain Eukaryota Chatton, 1925
     Metazoa Haeckel 1874 - multicellular animals see Kingdom Animalia Linnaeus, 1758
       Bilateria Hatschek, 1888 - bilaterians see Subkingdom Bilateria Hatschek, 1888
         Deuterostomia Grobben, 1908 - deuterostomes see Infrakingdom Deuterostomia Grobben, 1908
           Phylum Chordata Bateson, 1885 - chordates
             Subphylum Vertebrata Cuvier, 1812 - vertebrates see Infraphylum Vertebrata Lamarck, 1801
               Class "Agnatha" Cope, 1889
                 Subclass †unnamed see Class Cephalaspidomorphi Kiaer & Stensiö, 1920
                   1 Order †Osteostraci Lankester, 1868 - osteostracans see Order Cephalaspidiformes Halstead Tarlo, 1967
                   2 Order †Galeaspida Liu, 1965 see Order Galeaspidiformes
                   3 Order †Pituriaspida Young, 1991 see Order Pituriaspidiformes