Chelicerata Heymons, 1901 †Eurypterida Burmeister, 1843 - eurypterids †Eurypterina Burmeister, 1843 †Diploperculata Lamsdell, Hoşgör & Selden, 2013 Superfamily †Adelophthalmoidea Tollerton, 1989 [monotypic] Family †Adelophthalmidae Tollerton, 1989 Genus †Pittsfordipterus Kjellesvig-Waering & Leutze, 1966