This list of eurypterid genera is a comprehensive listing of all genera that have ever been included in the order Eurypterida, excluding purely vernacular terms. The list includes all commonly accepted genera, but also genera that are now considered invalid, doubtful (nomen dubium), or were not formally published (nomen nudum), as well as junior synonyms of more established names and genera that are no longer considered eurypterids. The list currently includes 124 names, out of which 78 are considered valid eurypterid genera.
There are approximately 250 species of eurypterids recognized as valid.
Naming conventions and terminology There is no "official" or "canonical" list of eurypterid genera. The closest thing is found contained in the regularly updated Summary list of fossil spiders and their relatives in the World Spider Catalog. The vast majority of the content of the list below, including the valid genera, preoccupied names, junior synonyms, taxonomical classifications and sites of discovery, is based upon the 2018 edition of the Summary list. Content not based on the list, such as genera described after its publication, is noted through inline citations.
Naming conventions and terminology follow the International Code of Zoological Nomenclature. Technical terms used include: Junior synonym: A name which describes the same taxon as a previously published name. If two or more genera are formally designated and the type specimens are later assigned to the same genus, the first to be published (in chronological order) is the senior synonym, and all other instances are junior synonyms. Senior synonyms are generally used, except by special decision of the ICZN, but junior synonyms cannot be used again, even if deprecated. Junior synonymy is often subjective, unless the genera described were both based on the same type specimen. Nomen nudum (Latin for "naked name"): A name that has appeared in print but has not yet been formally published by the standards of the ICZN. Nomina nuda (the plural form) are invalid, and are therefore not italicized as a proper generic name would be. If the name is later formally published, that name is no longer a nomen nudum and will be italicized on this list. Often, the formally published name will differ from any nomina nuda that describe the same specimen. Nomen manuscriptum (Latin for "manuscript name"): A name that appears in manuscript of a formal, but not-peer-reviewed, publication that has no scientific backing. A nomen manuscriptum is equivalent to a nomen nudum for everything except the method of publication, and description. Nomen oblitum (Latin for "forgotten name"): A name that has not been used in the scientific community for more than fifty years after its original proposal. Preoccupied name: A name that is formally published, but which has already been used for another taxon. This second use is invalid (as are all subsequent uses) and the name must be replaced. As preoccupied names are not valid generic names, they will also go unitalicized on this list. Nomen dubium (Latin for "dubious name"): A name describing a fossil with no unique diagnostic features.
Eurypterid genera
+GenusAuthor(s)YearStatusAgeLocationNotesAcanthoeurypterusKjellesvig-WaeringN/AJr. synonymN/AN/ANomen manuscriptum, also considered as a synonym of Eurypterus.AcutiramusRuedemann1935ValidSilurian - Devonian
AdelophthalmusJordan1854ValidDevonian - PermianNearly cosmopolitan, see article.AlkenopterusStørmer1974ValidDevonian AlloeurypterusKjellesvig-WaeringN/AJr. synonymN/AN/ANomen manuscriptum, also considered as a synonym of Eurypterus.AngustidontusCooper1936MisidentificationN/AN/AMisidentified, a crustacean.AnthraconectesMeek & Worthen1868Jr. synonymN/AN/ASynonym of Adelophthalmus.AthenepterusLamsdell2025ValidSilurian BaltoeurypterusStørmer1973Jr. synonymN/AN/ASynonym of Eurypterus.BarusopterusLamsdell2025ValidSilurian BassipterusKjellesvig-Waering & Leutze1966ValidSilurian BelinuropsisMatthew1910Nomen dubiumCarboniferous Too poorly preserved to be assigned to any particular arthropod group.BembicosomaLaurie1899MisidentificationN/AN/AMisidentified, a stem genus on Planaterga.BorchgrevinkiumNovojilov1959MisidentificationDunlop, J. A., Penney, D. & Jekel, D. 2018. A summary list of fossil spiders and their relatives. In World Spider Catalog. Natural History Museum BernN/AN/AMisidentified, possibly a stem prosomapod.BrachyopterellaKjellesvig-Waering1966ValidSilurian BrachyopterusStørmer1951ValidOrdovician BunodellaMatthew1889Nomen dubiumSilurian Uncertain affinities, probably synonym of Acutiramus.BuffalopterusKjellesvig-Waering & Heubusch1962ValidSilurian CampylocephalusEichwald1860ValidCarboniferous - Permian CampylognathusDiener1924PreoccupiedN/AN/APreoccupied by a genus of plant bugs, changed to Campylocephalus.CarcinosomaClaypole1890ValidSilurian
CiurcopterusTetlie & Briggs2009ValidSilurian ClarkeipterusKjellesvig-Waering1966ValidSilurian ClintonipterusKjellesvig-WaeringN/ANomen nudumN/AN/AInformal name that only appears in notes in museum drawers.CruinnopterusLamsdell2025ValidSilurian
CtenopterusClarke & Ruedemann1912ValidSilurian CurviramusRuedemann1935Jr. synonymN/AN/ASynonym of Pterygotus.CyrtoctenusStørmer & Waterston1968DebatedDevonian - Carboniferous
Hibbertopterid taxonomy unresolved, possibly synonym of Hibbertopterus or another genus.DolichocephalaClaypole1883PreoccupiedN/AN/APreoccupied by a genus of flies, synonym of Hallipterus.DolichopterusHall1859ValidSilurian DorfopterusKjellesvig-Waering1955Misidentification?Devonian Eurypterid affinities questioned. May not be an arthropod at all.DrepanopterusLaurie1892ValidSilurian - Devonian
DunsopterusWaterston1968DebatedCarboniferous Hibbertopterid taxonomy unresolved, possibly synonym of Hibbertopterus or another genus.EchinognathusWalcott1882ValidOrdovician EocarcinosomaCaster & Kjellesvig-Waering1964ValidOrdovician ErettopterusSalter1859ValidSilurian - Devonian
ErieopterusKjellesvig-Waering1958ValidSilurian - Devonian EidotheaScouler1831PreoccupiedN/AN/APreoccupied name, changed to Campylocephalus.EurypterellaMatthew1888Nomen dubiumCarboniferous Too poorly preserved to be assigned to any particular arthropod group.Eurypterusde Kay1825ValidSilurian
EurysomaClaypole1890PreoccupiedN/AN/APreoccupied name, changed to Carcinosoma.EusarcanaStrand1942ValidSilurian - Devonian
EusarcusGrote & Pitt1875PreoccupiedN/AN/APreoccupied name, changed to Eusarcana.EysyslopterusTetlie & Poschmann2008ValidSilurian GlaucodesPruvost1923Jr. synonymN/AN/ASynonym of Mycterops.GlyptoscorpiusPeach1882DebatedN/A Synonym of Adelophthalmus or a hibbertopterid genus (or synonym).GrossopterusStørmer1934ValidDevonian HallipterusKjellesvig-Waering1963ValidDevonian HardieopterusWaterston1979ValidSilurian HastimimaWhite1908ValidPermian
HerefordopterusTetlie2006ValidSilurian HibbertopterusKjellesvig-Waering1959ValidCarboniferous
HimantopterusSalter1856PreoccupiedN/AN/AUnavailable junior homonym, replaced by name ErettopterusHolmipterusKjellesvig-Waering1979ValidSilurian HughmilleriaSarle1903ValidSilurian HunanopterusLamsdell2025ValidSilurian JaekelopterusWaterston1964ValidDevonian KiaeropterusWaterston1979ValidSilurian KockurusChlupáč1995MisidentificationN/AN/AMisidentified, likely represents an aglaspidid.KodymirusChlupáč1995MisidentificationN/AN/AMisidentified, likely represents an aglaspidid.KokomopterusKjellesvig-Waering1966ValidSilurian LanarkopterusRitchie1968ValidSilurian LamontopterusWaterston1979ValidSilurian LaurieipterusKjellesvig-Waering1966ValidSilurian LeiopterellaLamsdell, Braddy, Loeffler & Dineley2010Jr. synonymN/AN/ASynonym of Pagea.LepidodermaReuss1855Jr. synonymN/AN/ASynonym of Adelophthalmus.MalongiaWang et al.2022ValidDevonian MarsupipterusCaster & Kjellesvig-Waering1955MisidentificationN/AN/AMisidentified, a phyllocarid crustacean.MazonipterusKjellesvig-Waering1963MisidentificationN/AN/AMisidentified, a plant.MegalograptusMiller1874ValidOrdovician MegarachneHünicken1980ValidCarboniferous - Permian MelbournopterusCaster & Kjellesvig-Waering1953MisidentificationN/AN/AMisidentified, a brachipod.MixopterusRuedemann1921ValidSilurian
MoselopterusStørmer1974ValidDevonian MycteropsCope1886ValidCarboniferous
NanahughmilleriaKjellesvig-Waering1961ValidSilurian - Devonian
NecrogammarusWoodward1870Nomen dubiumSilurian Possibly a synonym of Erettopterus.OnychopterellaStørmer1951ValidOrdovician - Silurian OnychopterusMiller & Gurley1896PreoccupiedStørmer, Leif. "A new eurypterid from the Ordovician of Montgomeryshire, Wales." Geological Magazine; November 1951; v. 88; no. 6; p. 409-422.N/AN/APreoccupied name, changed to Onychopterella.OrcanopterusStott, Tetlie, Braddy, Nowlan, Glasser & Devereux2005ValidOrdovician PageaWaterston1962ValidDevonian ParacarcinosomaCaster & Kjellesvig-Waering1964Jr. synonymN/AN/ASynonym of Eusarcana.ParaeurypterusLamsdell, Hoşgör & Selden2013ValidOrdovician ParahughmilleriaKjellesvig-Waering1961ValidSilurian - Devonian
ParastylonurusKjellesvig-Waering1966ValidSilurian ParkaFleming1831MisidentificationN/AN/AMisidentified, a plant.PentecopterusLamsdell et al.2015ValidOrdovician PentlandopterusLamsdell, Hoşgör & Selden2013ValidOrdovician PittsfordipterusKjellesvig-Waering & Leutze1966ValidSilurian PolystomurumNovojilov1958MisidentificationN/AN/AMisidentified, an unplaced euchelicerate.PolyzosternitesGoldenberg1873Jr. synonymN/AN/ASynonym of Adelophthalmus.PterygotusAgassiz1839ValidSilurian - DevonianNearly cosmopolitan, see article.QujingopterusMa et al.2025ValidDevonian Possibly a synonym of Soligorskopterus.RhenopterusStørmer1936ValidDevonian RhinocarcinosomaNovojilov1962ValidSilurian RuedemannipterusKjellesvig-Waering1966ValidSilurian SalteropterusKjellesvig-Waering1951ValidSilurian SelkiepterellaLamsdell2025ValidSilurian SidneyiaWalcott1911MisidentificationN/AN/AMisidentified, an arachnomorph.SlimoniaPage1856ValidSilurian
SoligorskopterusPlax, Lamsdell, Vrazo & Barbikov2018ValidDevonian StoermeropterusLamsdell2011ValidDevonian
StrabopsBeecher1901MisidentificationN/AN/AMisidentified, a strabopid.StrobilopterusRuedemann1935ValidSilurian - Devonian StylonurellaKjellesvig-Waering1966ValidSilurian - Devonian StylonuroidesKjellesvig-Waering1966ValidSilurian StylonurusPage1856ValidDevonian SyntomopterellaTellie2007Jr. synonymN/AN/ASynonym of Strobilopterus.SyntomopterusKjellesvig-Waering1961PreoccupiedN/AN/APreoccupied name, changed to Strobilopterus.TarsopterellaStørmer1951ValidDevonian TarsopterusClarke & Ruedemann1912PreoccupiedN/AN/APreoccupied name, changed to Tarsopterella.TerropterusWang, Dunlop, Gai, Lei, Jarzembowski & Wang2021ValidSilurian TigrisopterusWang, Sun & Zhang2025ValidDevonian TruncatiramusKjellesvig-Waering1961Jr. synonymN/AN/ASynonym of Erettopterus.TylopterellaStørmer1951ValidSilurian TylopterusClarke & Ruedemann1912PreoccupiedN/AN/APreoccupied name, changed to Tylopterella.UnionopterusChernyshev1948ValidCarboniferous VinetopterusPoschmann & Tellie2004ValidDevonian VernonopterusWaterston1968DebatedCarboniferous Hibbertopterid taxonomy unresolved, possibly synonym of Hibbertopterus or another genus.WaeringopterusLeutze1961ValidSilurian WaterstonopterusLamsdell2025ValidSilurian WiedopterusPoschmann2015ValidDevonian WillwerathiaStørmer1936MisidentificationN/AN/AMisidentified, a xiphosuran.WoodwardopterusKjellesvig-Waering1959ValidCarboniferous
Eurypterid ichnogenera +GenusAuthor(s)YearStatusAgeLocationNotesArcuitesVrazo & Ciurca2017ValidSilurian MerostomichnitesHanken, N.-M. & Størmer, L. (1975): "The trail of a large Silurian eurypterid". Fossils and Strata, No. 4, pp. 255-270, Pl. 1 -3.Packard1900ValidOrdovician - Silurian Merostomichnites tracks in Norway were likely made by the genus Mixopterus.PalmichniumRichter1954ValidDevonian - Carboniferous
See also Timeline of eurypterid research List of xiphosuran genera List of trilobite genera List of ammonite genera