Atlantic horseshoe crab

Species of horseshoe crab

The Atlantic horseshoe crab (Limulus polyphemus) is a marine arthropod found along the Atlantic coast of North America. Despite its name, it is more closely related to arachnids such as spiders and scorpions than to true crabs.

Description

A horseshoe crab on the beach

The Atlantic horseshoe crab is characterized by its hard, dome-shaped carapace, which is often brownish-green in color. The body is divided into three sections: the prosoma (head), opisthosoma (abdomen), and the telson (tail spine). The prosoma houses the central nervous system and the eyes, while the opisthosoma contains the gills and reproductive organs. The telson is used for steering and flipping the animal over if it becomes overturned.

Habitat and Distribution

Horseshoe crab on the coast

Atlantic horseshoe crabs are found in shallow coastal waters from Maine to the Yucatán Peninsula. They prefer sandy or muddy bottoms where they can burrow and search for food. During the breeding season, they migrate to beaches to lay their eggs.

Diet

Horseshoe crabs are omnivorous scavengers. They feed on a variety of organisms, including small mollusks, worms, and algae. Their feeding habits play a crucial role in the coastal ecosystem by recycling nutrients.

Reproduction

Horseshoe crab with shells

Reproduction occurs during the spring and summer months when horseshoe crabs come ashore to spawn. Females lay thousands of eggs in the sand, which are then fertilized by the males. The eggs hatch into larvae that resemble miniature adults and undergo several molts before reaching maturity.

Ecological Importance

Close-up of a horseshoe crab

The eggs of the Atlantic horseshoe crab are a vital food source for migratory birds, particularly the red knot. The decline in horseshoe crab populations has been linked to decreases in bird populations that rely on their eggs.

Medical Uses

The blue blood of the horseshoe crab contains a substance called Limulus Amebocyte Lysate (LAL), which is used to test for bacterial endotoxins in medical applications. This has made the horseshoe crab an invaluable resource in the biomedical industry.

Conservation

Female horseshoe crab

The Atlantic horseshoe crab is considered a species of concern due to habitat loss, overharvesting for bait, and biomedical use. Conservation efforts are underway to ensure sustainable populations, including restrictions on harvesting and habitat protection.

Related pages

• Horseshoe crab
• Limulus Amebocyte Lysate
• Red knot