[Phylum] [Arthropoda] Siebold, 1848 - arthropods
   Chelicerata Heymons, 1901
     Euchelicerata Weygoldt & Paulus, 1979
       [Order] †Eurypterida Burmeister, 1843 - eurypterids
         1 [Suborder] †Stylonurina Diener, 1924
         2 [Suborder] †Eurypterina Burmeister, 1843
         3 Genus †Dorfopterus Kjellesvig-Waering, 1955, incertae sedis
         4 Genus †Holmipterus Kjellesvig-Waering, 1979, incertae sedis
         5 Genus †Marsupipterus Caster & Kjellesvig-Waering, 1955, incertae sedis
         6 Genus †Unionopterus Chernyshev, 1948, incertae sedis