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Nature

Horseshoe Crab

What is horseshoe crab?

· Emily Grant

Key facts

family Limulidae[2]
order Xiphosura[3]
phylum Arthropoda[1]
scientific name Limulus polyphemus[3]
body parts cephalothorax, abdomen, telson[2]
common name Atlantic horseshoe crab[1]

A horseshoe crab is a marine arthropod with a horseshoe-shaped body, not a true crab.

Context

Horseshoe crabs are not true crabs but marine arthropods. They are more closely related to arachnids such as spiders and scorpions. The name comes from their distinctive horseshoe-shaped body. The Atlantic horseshoe crab is often referred to as a “living fossil” and can be found along U.S. coastlines from Maine to Mexico [1].

Documented claims

  • Horseshoe crabs are not crabs or crustaceans; they are chelicerates, closer to arachnids. [2]
  • The name comes from the animal’s horseshoe-shaped body. [2]
  • The Atlantic horseshoe crab has been called a “living fossil.” [1]
  • Atlantic horseshoe crabs occur on U.S. coastlines from Maine to Mexico. [1]

Questions and answers

What is so special about horseshoe crab?

Horseshoe crabs are special because they are not true crabs but marine arthropods. They are more closely related to arachnids and have a distinctive horseshoe-shaped body [2].

How rare is it to find a horseshoe crab?

Atlantic horseshoe crabs are found along U.S. coastlines from Maine to Mexico, but their populations can vary by region. They are not extremely rare but are considered ecologically important [1].

Sources

  1. horseshoe crab summary | Britannica — britannica.com (retrieved August 3, 2026)
  2. Horseshoe Crabs — dnr.sc.gov (retrieved August 3, 2026)
  3. Blue-bloods of the sea - Lab Animal — nature.com (retrieved August 3, 2026)

Sources last checked August 3, 2026. · More in Nature