List of xiphosuran genera

This list of xiphosurans is an attempt to create a comprehensive listing of all genera that have ever been included in the class xiphosura, excluding purely vernacular terms. The list includes all commonly accepted genera, but also genera that are now considered invalid, doubtful (nomina dubia), or were not formally published (nomina nuda), as well as junior synonyms of more established names, and genera that are no longer considered xiphosurans.

The list includes 39 genera.

• Extinct genera are marked with a dagger (†).
• Extant genera are bolded.

Naming conventions and terminology

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 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. As this can be an extremely subjective and controversial designation, this term is not used on this list.

The List

Genus	Authors	Year	Status	Age	Location	Notes	Images
†Anacontium	Raymond	1944	Valid.				Tachypleus. Limulus. File:Limuluskils4.jpg Limulus.
†Archeolimulus	Chlupác	1963	Valid.		Europe.
†Austrolimulus	Riek	1955	Valid.
†Bellinuroopsis	Chernyshev	1933	Valid.
†Bellinurus	Meek & Worthen	1865	Valid.
†Bembicosoma	Laurie	1899	Valid.
†Bunaia	Clarke	1920	Valid.
†Bunodella	Matthew	1889	Valid.
†Bunodes	Eichwald	1854	Valid.
Carcinoscorpius	Pocock	1902	Valid.
†Casterolimulus	Holland Erickson O'Brien 1975	1975	Valid.
†Cyamocephalus	Currie	1927	Valid.
†Elleria	Raymond	1944	Valid.
†Euproops	Meek	1876	Valid.
†Heterolimulus	Via Boada de Villalta	1966	Valid.
†Kasibelinurus	Pickett	1993	Valid.
†Kiaeria	Størmer	1934	Valid.
†Legrandella	Eldredge	1974	Valid.
†Lemoneites	Flower	1969	Valid.
†Limulitella	Størmer	1952	Valid.
†Limuloides	Woodward	1865	Valid.
Limulus	Muller	1785	Valid.
†Liomesaspis	Raymond	1944	Valid.
†Lunataspis	Name	19##	Valid.
†Mesolimulus	Størmer	1952	Valid.
†Moravurus	Pribyl	1967	Valid.
†Neobelinuropsis	Eller	1938	Valid.
†Neolimulus	Woodward	1868	Valid.
†Paleolimulus	Dunbar	1923	Valid.
†Palaeomerus	Name	19##	Valid.
†Pasternakevia	Selden Drygant	1987	Valid.
†Pringlia	Raymond	1944	Valid.
†Protolimulus	Packard	1886	Valid.
†Psammonlimulus	Name	19##	Valid.
†Pseudoniscus	Nieszkowski	1859	Valid.
†Rolfeia	Waterston	1985	Valid.
Tachypleus	Leach	1819	Valid.
†Valloisella	Racheboeuf	1992	Valid.
†Victalimulus	Riek Gill	1971	Valid.
†Weinbergina	Richter Richter	1929	Valid.
†Willwerathia	Stormer	1969	Valid.
†Xaniopyramis	Siveter Selden	1987	Valid.

See also

• Horseshoe Crab
• Living fossil