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 Annelida Lamarck, 1809 - segmented worms
           1 Class Polychaeta Grube, 1850 - polychaetes
           2 Class Hirudinoidea see Class Clitellata Michaelsen, 1919
           3 Class Oligochaeta Grube, 1850 - oligochaetes see [unranked] oligochaetous Clitellata
           4 Class Afrenulata see Family Siboglinidae Caullery, 1914