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	Name	19##	Valid.		Europe.
†Austrolimulus	Name	19##	Valid.
†Bellinuroopsis	Chernyshev	1933	Valid.
†Bellinurus	Buckland	1837	Valid.
†Bembicosoma	Laurie	1899	Valid.
†Bunaia	Name	19##	Valid.
†Bunodella	Matthew	1889	Valid.
†Bunodes	Name	19##	Valid.
Carcinoscorpius	Name	19##	Valid.
†Casterolimulus	Name	19##	Valid.
†Cyamocephalus	Name	19##	Valid.
†Elleria	Name	19##	Valid.
†Euproops	Name	19##	Valid.
†Heterolimulus	Name	19##	Valid.
†Kasibelinurus	Name	19##	Valid.
†Kiaeria	Name	19##	Valid.
†Legrandella	Name	19##	Valid.
†Lemoneites	Name	19##	Valid.
†Limulitella	Name	19##	Valid.
†Limuloides	Name	19##	Valid.
Limulus	Name	19##	Valid.
†Liomesaspis	Name	19##	Valid.
†Lunataspis	Name	19##	Valid.
†Mesolimulus	Name	19##	Valid.
†Moravurus	Name	19##	Valid.
†Neobelinuropsis	Name	19##	Valid.
†Neolimulus	Name	19##	Valid.
†Paleolimulus	Name	19##	Valid.
†Palaeomerus	Name	19##	Valid.
†Pasternakevia	Name	19##	Valid.
†Pringlia	Name	19##	Valid.
†Protolimulus	Name	19##	Valid.
†Psammonlimulus	Name	19##	Valid.
†Pseudoniscus	Name	19##	Valid.
†Rolfeia	Name	19##	Valid.
Tachypleus	Name	19##	Valid.
†Valloisella	Name	19##	Valid.
†Victalimulus	Name	19##	Valid.
†Weinbergina	Name	19##	Valid.
†Willwerathia	Name	19##	Valid.
†Xaniopyramis	Name	19##	Valid.

See also

• Horseshoe Crab
• Living fossil