[Bilateria] Hatschek, 1888 - bilaterians see Subkingdom Bilateria Hatschek, 1888
   ecdysozoans see Clade Ecdysozoa Aguinaldo, Turbeville, Linford, Rivera, Garey, Raff & Lake 1997, nom. cl. inval.
     Arthropoda Siebold, 1848 - arthropods
       Arachnomorpha Heider, 1913
         1.1 Order †Limulavida Walcott, 1911
         1.2.1 Subclass †Aglaspidida (Walcott, 1911) Bergström, 1968 see Order Aglaspidida Walcott, 1911
         1.2.2 chelicerates see Superclass Chelicerata Heymons, 1901
         1.2.3 Order †Cheloniellida Broili, 1933
         2 †Trilobitomorpha Størmer, 1944 see Superclass Trilobitomorpha Størmer, 1944