The Horseshoe Crab

Horseshoe crabs are marine and brackish water arthropods of the family Limulidae, suborder Xiphosurida, and order Xiphosura. They live primarily in and around shallow coastal waters on soft sandy or muddy bottoms. They occasionally come onto shore to mate. They are commonly eaten in Asia, and used as fishing bait, in fertilizer and in science (especially Limulus amebocyte lysate). In recent years, population declines have occurred as a consequence of coastal habitat destruction and overharvesting. Because of their origin 450 million years ago, horseshoe crabs are considered living fossils. Tetrodotoxin (TTX) may be present in Carcinoscorpius rotundicauda. TTX is a potent neurotoxin. Its name derives from Tetraodontiformes, an order that includes pufferfish, porcupinefish, ocean sunfish, and triggerfish; several of these species carry the toxin. Credit: Wikipedia.