Crustaceans are a sub-division of arthropod, a group which also includes spiders, insects and many more. However, this category on our web store details crustacean which belong to the families of crabs, lobsters, shrimps and more, mainly marine dwelling arthropods. These animals have been around since the late Cambrian period and at one point were the dominant life forms in the sea and land, however, evolution of larger predators have resulted in them being preyed upon by larger animals. Their long fossil record allows geologists to precisely map their evolution right from their start to the present day. In this section, you willfnid various fossil specimens of crabs, lobsters, crayfish and shrimp for sale.