[Phylum] [Arthropoda] Siebold, 1848 - arthropods
   Chelicerata Heymons, 1901
     Euchelicerata Weygoldt & Paulus, 1979
       Xiphosura Latreille, 1802 - horseshoe crabs see Class Xiphosura Latreille, 1802
         Prosomapoda Lamsdell, 2013
           [Class] Xiphosura Latreille, 1802 [monotypic] - horseshoe crabs
             [Order] Xiphosurida Latreille, 1802
               [Suborder] †Belinurina Bergström, 1975
                 1 Family †Belinuridae Packard, 1886
                 2 Genus †Xiphosuroides Shpinev & Vasilenko, 2018, incertae sedis