Chelicerata Heymons, 1901
   †Eurypterida Burmeister, 1843 - eurypterids
     1 †Stylonurina Diener, 1924
     2 †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