Chelicerata Heymons, 1901
   †Eurypterida Burmeister, 1843 - eurypterids
     †Eurypterina Burmeister, 1843
       †Diploperculata Lamsdell, Hoşgör & Selden, 2013
         1 Superfamily †Carcinosomatoidea Størmer, 1934
         2 Superfamily †"Waeringopteroidea" nom. ined.
         3 Superfamily †Adelophthalmoidea Tollerton, 1989 [monotypic]
         4 Superfamily †Pterygotioidea Dunlop, Penney & Jekel, 2010, orth. inval. see Superfamily Pterygotoidea Clarke & Ruedemann, 1912