Chelicerata Heymons, 1901
   †Eurypterida Burmeister, 1843 - eurypterids
     †Stylonurina Diener, 1924
       Superfamily †Stylonuroidea Kjellesvig-Waering, 1959
         1 Family †Parastylonuridae Waterston, 1979
         2 Family †Stylonuridae Diener, 1924