Context:
Recently,Environmental groups petitioned the U.S. government seeking protection for the American horseshoe crab, a “living fossil”.
About Horseshoe Crab
- These are Marine and brackish water arthropods belonging to the Limulidae family.
- Ancient Origins : Thrived for over 450 million years, predating dinosaurs.
- Appearance:
- It resembles prehistoric crabs, but closer relatives are scorpions and spiders.
- Habitat : They prefer shallow coastal waters with soft sandy or muddy bottoms.
- Spawning: They migrate to intertidal beaches for spawning, primarily during summer-spring high tides.
- This timing ensures their eggs are deposited in moist sand, essential for development.
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Type of Horseshoe Crab Species & Habitat
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- Atlantic or American horseshoe crab (Limulus polyphemus):
- Found on the Atlantic coast of the US and the Southeast Gulf of Mexico.
- IUCN Status: Vulnerable
- Tri-spine horseshoe crab (Tachypleus tridentatus):
- Coastal waters of Odisha (India), southeast Asia, China, and Japan.
- IUCN: Endangered
- Coastal horseshoe crab (Tachypleus gigas): Similar range as the tri-spine species.
- Mangrove horseshoe crab (Carcinoscorpius rotundicauda): Found in mangrove habitats of Southeast Asia.
Concerns with their Medical Use :
- Pharmaceutical companies reap horseshoe crabs in large numbers for their bright blue blood which contains a special clotting agent limulus amebocyte lysate (LAL) which detects a contaminant called endotoxin.
- It is used to test vaccines, drugs and medical devices to ensure that they aren’t contaminated with dangerous bacterial toxins.
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Threats
- They face threats due to Commercial Harvest for food, bait & Biomedical Use and Habitat loss : Coastal Reclamation & Development, Shoreline Alteration, Climate change etc
Conservation Efforts To Horseshoe Crab
- In India: Placed in Schedule IV of the Wildlife (Protection) Act 1972 in 2009.
- This inclusion means that catching and killing a horseshoe crab is an offense.
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- It placed them into the Red list of Threatened species.
- It observes International Horseshoe crab Day on 20th June.
What are Living Fossils ?
- Living fossils are the species that have survived for millions of years, retaining identical traits to their ancestors from ancient times.
- These organisms are offering invaluable clues about the evolutionary journey and the ecological landscape of ancient Earth.
Other Examples of Living Fossils
- Coelacanth: It was rediscovered in 1938 off the coast of South Africa.
- This deep-sea fish, characterised by its lobed fins functioning somewhat akin to limbs.
- Ginkgo Biloba: Sole surviving member of an ancient group of plants.
- Its distinctive fan-shaped leaves have remained unchanged for millions of years.
- Wollemi Pine: Unearthed in 1994 in Australia, the Wollemi Pine is a rare plant.
- Tuatara: Exclusive to New Zealand, the tuatara is a reptilian species.
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Also Read: New Marine Amphipod Species Found In Chilika Lake
News Source: The Hindu
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February 15, 2024