What is Horseshoe crab?
{{Taxobox | box_width = 250px | name = Horseshoe crab | image = Limule(dD).jpg | image_width = 200px | image_caption = Horseshoe crab | regnum = [[Animal]]ia | phylum = [[Arthropoda]] | subphylum = [[Chelicerata]] | classis = [[Merostomata]] | ordo = [[Xiphosura]] | familia = [[Limulidae]] | genus = '''''Limulus'''''}} [[File:LimuleFace.jpg|thumb|right|200px|Tiny eyes can be seen.]] [[File:Limulus polyphemus(bottom).jpg|thumb|right|200px|The vital organs and [[appendage]]s are protected by the carapace.]] The '''horseshoe crab''' is a [[benthic]] or bottom-dwelling creature. It is not a [[crab]] at all, but a relative of the [[arachnid]]s. Its main [[habitat]]s are [[coast]]al areas and river [[estuary|estuaries]]. ''Limulus polyphemus'' is the best-known of the four [[species]]. ==Description== On its [[dome]]-shaped [[carapace]], the horseshoe crab has four small [[eye]]s. It has two [[wikt:compound|compound]] [[eye]]s at the sides of the carapace, and two simple eyes on the front. A horseshoe crab has twelve legs: five pairs of walking [[leg]]s and a set of tiny pincers. The long, spiky tail is not used as a [[weapon]] or for defense; instead, it is just used for steering and flipping the body over if it gets turned upside down. == Distribution == === Atlantic === Atlantic horseshoe crabs, ''Limulus polyphemus'', can be found all over the eastern coast of [[North America]] and [[Mexico]]. Buried under [[mud]] or [[sand]], they eat small [[clam]]s, [[crustacean]]s, and [[worm]]s. All over the coast, you will find their [[Animal shell|shells]] washed up on shore. Some of these [[Animal shell|shells]] are quite big, as the horseshoe crab can grow up to two feet long and a foot wide. Horseshoe crabs go through [[moult]]s to reach that size. The horseshoe crab population ranges from the [[Yucatán Peninsula]] to northern [[Maine]], but they are most commonly found in the mid-[[Atlantic]] region between [[Virginia]] and [[New Jersey]]. Each major estuary along the coast has its own horseshoe crab population, d