organisms see Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
   Kingdom Animalia Linnaeus, 1758 - animals
     Subkingdom Eumetazoa Butschli, 1910 see [unranked] Eumetazoa Bütschli, 1910
       Bilateria Hatschek, 1888 see Subkingdom Bilateria Hatschek, 1888
         Coelomata see [unranked] Coelomates Hyman, 1951
           Series Protostoma
             Phylum Arthropoda Siebold, 1848 - arthropods
               Subphylum Chelicerata Heymons, 1901
                 1 Class Pycnogonida Latreille, 1810 - pycnogonids
                 2 Class Merostomata Dana, 1852 - horseshoe crabs see Class Xiphosura Latreille, 1802
                 3 Class Arachnida Lamarck, 1801