[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
           1 Genus †Anderella Moore, McKenzie & Lieberman, 2007
           2 Genus †Borchgrevinkium Novojilov, 1958
           3 Genus †Camanchia Moore, Briggs, Braddy & Shultz, 2011
           4 Genus †Legrandella Eldredge, 1974
           5 Genus †Venustulus Moore, 2005
           6 Family †Weinberginidae Richter & Richter, 1929 [monotypic]
           7 Planaterga Lamsdell, 2013
           8 [Class] Xiphosura Latreille, 1802 [monotypic] - horseshoe crabs