Arthropoda Siebold, 1848 - arthropods
   Euarthropoda
     Subphylum Chelicerata Heymons, 1901
       Euchelicerata Weygoldt & Paulus, 1979
         Prosomapoda Lamsdell, 2013
           Xiphosura Latreille, 1802 - horseshoe crabs
             Order Xiphosurida Latreille, 1802
               1.1 Limulina Richter & Richter, 1929
               1.2 †Bellinurina Zittel & Eastman, 1913
               2 Genus †Lunataspis Rudkin, Young & Nowlan, 2008
               3 Genus †Elleria Raymond, 1944, nom. dub.
               4 Genus †Kiaeria Størmer, 1934