The other three species are also called horseshoe crabs. The Japanese horseshoe crab ("Tachypleus tridentatus") is found in the Seto Inland Sea, and is considered an endangered species because of loss of habitat. Two other species occur along the east coast of India: "Tachypleus gigas" and "Carcinoscorpius rotundicauda". All four are quite similar in form and behavior.