Horseshoe Crabs

About Horseshoe crabs:

• The horseshoe crab is a marine chelicerate arthropod living in shallow coastal waters on soft sandy or muddy bottoms and spawns mostly on intertidal beaches at summer-spring high tides. 
• The Chelicerata is a division within the Arthropoda, containing animals such as spiders, scorpions, harvestmen, mites and ticks. Like all arthropods, they have a segmented body and segmented limbs and a thick chitinous cuticle called an exoskeleton.
• It is known as a marine ‘living fossil’.
• There are four extant horseshoe crab species:
  • The American horseshoe crab (Limulus polyphemus) along the eastern coast of the USA and in the Gulf of Mexico,
  • The tri-spine horseshoe crab (Tachypleus tridentatus),
  • The coastal horseshoe crab (Tachypleus gigas) 
  • The mangrove horseshoe crab (Carcinoscorpius rotundicauda) 
• The last three are Indo-Pacific species found mainly in the coastal waters of India, Southeast Asia, China and Japan.    
• Odisha is the largest habitat of horseshoe crabs in India.
• Conservation status in India
  • Wildlife Protection Act 1972: Schedule IV
• IUCN Status
  • American horseshoe crab: Vulnerable
  • Tri-spine horseshoe crab: Endangered
  • The two other species are not listed yet

 

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Q1) What is an arthropod?

An “arthropod” is an invertebrate animal that has an exoskeleton, a segmented body, and jointed appendages. The following families of organisms are all examples of arthropods. Examples : Spiders and scorpions.

Source: Horseshoe crabs’ disappearing off Odisha has scientists alarmed