What is Crustacean?
{{Paraphyletic group | name = Crustacea | fossil_range = {{Fossil range|511|0}}<small>[[Cambrian]] to [[Holocene|present]]</small> | image = Abludomelita obtusata.jpg | image_caption = ''[[Abludomelita obtusata]]'', an [[amphipod]] | image_alt = A segmented animal is seen from the side. It has a long antennae and small black eyes; one pair of legs is much more robust than the others; the body is slightly arched and each segment carries a pair of appendages. The whole animal is translucent or a pale brown colour. | auto = yes | taxon = Crustacea | authority = | includes = [[Thylacocephala]]? †<br /> [[Branchiopoda]] :[[Phyllopoda]] :[[Fairy shrimp|Sarsostraca]] [[Remipedia]]<br/> [[Cephalocarida]]<br/> [[Maxillopoda]] :[[Thecostraca]] :[[Tantulocarida]] :[[Branchiura]] :[[Pentastomida]] :[[Mystacocarida]] :[[Copepod]]a [[Ostracod]]a :[[Myodocopa]] :[[Podocopa]] [[Malacostraca]] :[[Phyllocarida]] :[[Hoplocarida]] :[[Eumalacostraca]] | excludes = [[Hexapoda|Hexapods]] }} [[File:Nur01521 - Flickr - NOAA Photo Library.jpg|thumb|right|American [[lobster]]]][[File:Pandborealisind.jpg|thumb|right|Edible [[shrimp]]]] '''Crustaceans''' are a [[phylum|subphylum]] of [[arthropod]]s with 67,000 described [[species]]. They are part of the phylum [[Arthropoda]]. Crustaceans include [[crab]]s, [[lobster]]s, [[crayfish]], [[shrimp]], [[krill]] and [[barnacle]]s. They are relatives of [[insects]]. If the Arthropods are regarded as a [[superphylum]], then the insects and crustacea would be phyla (see [[List of animal phyla]]). The group has an extensive [[fossil]] record, reaching back to the [[Cambrian]]. Most crustaceans are [[aquatic]], mostly [[Ocean|marine]]. Some have moved onto land permanently. Crustaceans that live on land include some crabs, and [[woodlice]]. Crustacea range in size from a [[parasite]] 0.1mm long, to the [[Japanese spider crab]] with a leg span of up to 14&nbsp;ft (4.3 m) and a mass of 44&nbsp;lb (20&nbsp;kg). The North Atlantic [[lobster]] can weigh more than 40 pounds. Most crustaceans are [[motile