[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
           Class †Marrellomorpha Beurlen, 1934
             1 Order †Acercostraca Lehmann, 1955
             2 Order †Marrellida Raymond, 1935