†order Eurypterida Burmeister 1843 (eurypterid)
Synonyms: Cyrtoctenida Stoermer and Waterston 1968, Gigantostraca Haeckel 1896
Parent taxon: Chelicerata according to J. C. Lamsdell 2025
See also Bergström 1968, Dunlop et al. 2020, Lamsdell 2013, Sepkoski 2002 and Størmer 1955
Sister taxa: Euchelicerata, Gumatagichnus, Habeliida, Limulus nathorsti, Mollisoniida, Offacolidae, Sanctacaris
Subtaxa: Belinuropsis Belinuropsis wigudensis Eurypteracea Eurypterella Eurypterella ornata Eurypterina Marsupipterus Parahughmillera Stylonuracea Stylonurina