Chelicerata Heymons, 1901
   †Eurypterida Burmeister, 1843 - eurypterids
     †Eurypterina Burmeister, 1843
       †Diploperculata Lamsdell, Hoşgör & Selden, 2013
         Superfamily †Adelophthalmoidea Tollerton, 1989 [monotypic]
           1 Family †Adelophthalmidae Tollerton, 1989