Limulus

Limulus is a genus of horseshoe crab, with one extant species, the Atlantic horseshoe crab (Limulus polyphemus). One fossil species is currently assigned to the genus though several other species have been named, which have since been assigned to other genera.

Limulus Temporal range: Maastrichtian–Present PreꞒ Ꞓ O S D C P T J K Pg N
Modern L. polyphemus compared to the very similar Jurassic Crenatolimulus darwini
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Chelicerata
Order:	Xiphosura
Family:	Limulidae
Genus:	Limulus O. F. Müller, 1785[1]
Type species
Monoculus polyphemus[1] Linnaeus, 1758
Synonyms
Xiphosura

Currently valid species include:^[2]

• Limulus polyphemus (Linnaeus, 1758)
• Limulus coffini† Reeside & Harris, 1952- Pierre Shale, United States, Late Cretaceous (Maastrichtian)

Doubtful species include:^[3]

• Limulus nathorsti† Jackson, 1906- Jurassic, Sweden

Tentative species:^[3]

• "Limulus" decheni† Zinken, 1862- Paleogene, Germany (considered by some intermediate between Limulus and Tachypleus)^[3]

References

1. Hemming, Francis, ed. (1955). "Opinion 320: Validation, under the Plenary Powers, of the generic name Limulus Müller (O. F.), 1785 (class Merostomata) and confirmation of the entry of that name on the 'Official List of Generic Names in Zoology' (validation of an error in 'Opinion' 104)". Opinions and Declarations Rendered by the International Commission on Zoological Nomenclature. 9 (10): 149–169.
2. Bicknell, Russell D. C.; Błażejowski, Błażej; Wings, Oliver; Hitij, Tomaž; Botton, Mark L. (2021-03-02). Zhang, Xi‐Guang (ed.). "Critical re‐evaluation of Limulidae uncovers limited Limulus diversity". Papers in Palaeontology. 7 (3): 1525–1556. doi:10.1002/spp2.1352. ISSN 2056-2799. S2CID 233783546.
3. Dunlop, J. A., Penney, D. & Jekel, D. 2013. A summary list of fossil spiders and their relatives. In Platnick, N. I. (ed.) The world spider catalog, version 14.0 American Museum of Natural History, online at http://research.amnh.org/entomology/spiders/catalog/index.html