Limulus Polyphemus is species level organism and its common name is "horseshoe crab". Only four Limulus Polyphemus are alive nowadays and it is in phylum arthropoda. Limulus Polyphemus lives in aquqtic environment so that they are mostly found in American Atlantic Coast. The lives in “the shallow water over sand or in muddy bottoms” (Williams 1993). Therefore their habitat is temperate coastal or tropical coastal that it is humid but not cold.
Just as other animals, horseshoe crab needs to consume oxygen to stay alive. When they need to consume oxygen from outside environment, they use the gills (Williams). Like other arthropod, they use book gills (Williams). “Book -gills have fairly straightforward design for getting a lot of surface area exposed to the outside environment” (Williams). Book-gills have lamella and “there is double-walled chamber carbon dioxide with the outside water” (Williams).
Horseshoe crab can live for sixteen to seventeen years olds. They migrate into shore in late spring and during this time, male arrives first. The Female arrives in sand and makes a nest at a depth of 15-20cm (Sturtevant). In the nest, female horseshoe crab places eggs: then male comes in and fertilize the eggs (Sturtevant). “Studies in Delaware found that females laid an average of 3650 eggs per nest” (Sturtevant). “Development begins when the first egg cover split and new membrane, secreted by the embryo, forms a transparent spherical capsule” (Sturtevant). The larvae forms and these larvae swim for about five to seven days (Sturtevant). After swimming they settle, they settle, and begin the first molt: this happens approximately twenty days after the formation of egg capsule. As young horseshoes crabs grow, they move to deeper waters. During this time, molting still takes a place for two to three years (Sturtevant). They reach to sexual maturity after five to seven years (Sturtevant). The main cause of death in these days is “bait fish industry who harvests the horseshoe crabs” (Sturtevant).
Some of arthropod have mandibles, however horseshoe crab is jawless. They usually eat mollusk and worms and they use muscles to open and close esophagus
