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Clawed lobsters comprise a family (Nephropidae, sometimes also Homaridae) of large marine crustaceans. They have long bodies with muscular tails, and live in crevices or burrows on the sea floor. Three of their five pairs of legs have claws, including the first pair, which are usually much larger than the others. Highly prized as seafood, lobsters are economically important, and are often one of the most profitable commodities in coastal areas they populate. Commercially important species include two species of ''Homarus'' from the northern Atlantic Ocean, and scampi – the northern-hemisphere genus ''Nephrops'' and the southern-hemisphere genus ''Metanephrops''. Although several other groups of crustaceans have the word "lobster" in their names, the unqualified term "lobster" generally refers to the clawed lobsters of the family Nephropidae. Clawed lobsters are not closely related to spiny lobsters or slipper lobsters, which have no claws (''chelae''), or to squat lobsters. The closest living relatives of clawed lobsters are the reef lobsters and the three families of freshwater crayfish. == Description == Lobsters are invertebrates with a hard protective exoskeleton. Like most arthropods, lobsters must moult in order to grow, which leaves them vulnerable. During the moulting process, several species change colour. Lobsters have 10 walking legs; the front three pairs bear claws, the first of which are larger than the others. Although, like most other arthropods, lobsters are largely bilaterally symmetrical, some genera possess unequal, specialised claws. Lobster anatomy includes the cephalothorax which fuses the head and the thorax, both of which are covered by a chitinous carapace, and the abdomen. The lobster's head bears antennae, antennules, mandibles, the first and second maxillae, and the first, second, and third maxillipeds. Because lobsters live in a murky environment at the bottom of the ocean, they mostly use their antennae as sensors. The lobster eye has a reflective structure above a convex retina. In contrast, most complex eyes use refractive ray concentrators (lenses) and a concave retina. The abdomen includes swimmerets and its tail is composed of uropods and the telson. Lobsters, like snails and spiders, have blue blood due to the presence of hemocyanin which contains copper.〔(【引用サイトリンク】title=Copper for life – Vital copper )〕 In contrast, vertebrates and many other animals have red blood from iron-rich hemoglobin. Lobsters possess a green hepatopancreas, called the tomalley by chefs, which functions as the animal's liver and pancreas. Lobsters of the family Nephropidae are similar in overall form to a number of other related groups. They differ from freshwater crayfish in lacking the joint between the last two segments of the thorax, and they differ from the reef lobsters of the family Enoplometopidae in having full claws on the first three pairs of legs, rather than just one.〔 The distinctions from fossil families such as Chilenophoberidae are based on the pattern of grooves on the carapace.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「lobster」の詳細全文を読む スポンサード リンク
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