Limulus

Limulus Temporal range: Triassic to present
Modern L. polyphemus compared to the very similar Jurassic L. darwini
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Chelicerata
Class:	Xiphosura
Order:	Xiphosurida
Family:	Limulidae
Genus:	Limulus O. F. Müller, 1785
Type species
Limulus polyphemus (Linnaeus, 1758)

Limulus is a genus of horseshoe crab, with one extant species, the Atlantic horseshoe crab (Limulus polyphemus). Many fossil species are known, many of which have since been assigned to other genera.

Currently valid species include:

Tentative species:

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Wikipedia