[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
         †Trilobitomorpha Størmer, 1944 see Superclass Trilobitomorpha Størmer, 1944
           1 Class †Marrellomorpha Beurlen, 1934
           2 Order †Emeraldellida Størmer, 1944
           3 Order †Retifaciida Hou & Bergström, 1997
           4.1 Subclass †Concilioterga nom. null. see Subclass Conciliterga Hou & Bergström, 1997
           4.2 Subclass †Nectopleura Hou & Bergström, 1997
           4.3 Subclass †Petalopleura Hou & Bergström, 1997
           4.4 Subclass †Trilobita Walch, 1771 see Class Trilobita Walch, 1771