living organisms see Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
   Superkingdom Eukaryotae see Domain Eukaryota Chatton, 1925
     Kingdom Animalia Linnaeus, 1758 - animals
       Subkingdom Eumetazoa Butschli, 1910 see [unranked] Eumetazoa Bütschli, 1910
         Phylum Chordata Bateson, 1885 - chordates
           Subphylum Vertebrata Cuvier, 1812 - vertebrates
             Class Agnatha Cope, 1889
               Order Petromyzoniformes see Order Petromyzontiformes Berg, 1940
                 Family Petromyzonidae Bonaparte, 1831 see Family Petromyzontidae Bonaparte, 1832
                   Genus Petromyzon Linnaeus, 1758