horseshoe crab

American  

noun

1. a large marine arthropod, Limulus polyphemus, of shallow coastal waters of eastern North America and eastern Asia, having both compound and simple eyes, book gills, a stiff tail, and a brown carapace curved like a horseshoe: a living fossil related to the woodlouse.

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horseshoe crab British  

noun

1. Also called: king crab.  any marine chelicerate arthropod of the genus Limulus, of North America and Asia, having a rounded heavily armoured body with a long pointed tail: class Merostomata

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Etymology

Origin of horseshoe crab

First recorded in 1765–75

Example Sentences

In 1859 Charles Darwin coined the term “living fossil” to describe lineages that have looked the same for tens of millions of years, such as the coelacanth, sturgeon, and horseshoe crab.

From Science Magazine • Mar. 8, 2024

The fish follow along, hoping to eat anything the horseshoe crab misses.

From NewsForKids.net • Oct. 12, 2023

The tri-spine horseshoe crab has survived for more than 100 million years but now faces habitat destruction and overfishing for food and for its blood, used in the development of vaccines.

From BBC • Oct. 10, 2023

“Everything you do in life comes from horseshoe crab blood. Vaccines, antibiotics,” he said.

From Seattle Times • Jul. 30, 2023

The horseshoe crab is a primitive fossil of a beast, ancient and uncitified, but he is just as vulnerable to disorganization by endotoxin as a rabbit or a man.

From "The Lives of a Cell" by Lewis Thomas