[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] Limulina Richter & Richter, 1929
                 Superfamily Limuloidea Leach, 1819
                   Family Limulidae Leach, 1819
                     01 Genus †Albalimulus Bicknell & Pates, 2019
                     02 Genus †Allolimulus Lamsdell, 2020
                     03 Genus †Casterolimulus Holland, Erickson & O'Brien, 1975
                     04 Genus †Guangyuanolimulus Hu et al., 2022
                     05 Genus †Heterolimulus Via Boada & Villalta, 1966
                     06 Genus †Keuperlimulus Lamsdell, 2020
                     07 ?Genus †Limulitella Størmer, 1952
                     08 Genus †Mesolimulus Størmer, 1952
                     09 Genus †Ostenolimulus Lamsdell, Teruzzi, Pasini & Garassino, 2021
                     10 Genus †Sloveniolimulus Bicknell, Žalohar, Miklava, Celarc, Križnar & Hitij, 2019
                     11 Genus †Tarracolimulus Romero & Via Boada, 1977
                     12 Genus †Victalimulus Riek & Gill, 1971
                     13 Genus †Volanalimulus Lamsdell, 2020
                     14 Genus †Yunnanolimulus Zhang, Hu, Zhou, Iv & Bai, 2009
                     15 Subfamily Limulinae Leach, 1819
                     16 Subfamily Tachypleinae Pocock, 1902 [monotypic]