Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" (abdomen), usually hidden entirely under the thorax. They live in all the world's oceans, in freshwater, and on land, are generally covered with a thick exoskeleton, and have a single pair of pincers. They first appeared during the Jurassic Period.
King crabs are a taxon of decapod crustaceans that are chiefly found in cold seas. Because of their large size and the taste of their meat, many species are widely caught and sold as food with the most common being the red king crab.
The brown box crab is a king crab that lives from Prince William Sound, Alaska to San Diego, California, at depths of 0–547 metres (0–1,795 ft). It reaches a carapace length of 150 millimetres (5.9 in) and feeds on bivalves and detritus. The box crab gets its name from a pair of round tunnel-like openings that form between the claws and adjacent legs when the animal folds its limbs up against its body. Both claws, and their adjacent legs, have matching half-circle notches in them that line up to create a circle-shaped opening when the limbs are tightly pulled against one another. This tubular round opening is called a foramen. The crab often lies buried in the sediment, and the two foramens in the chelipeds allow water into the gill chamber for respiration. The gill chamber is also sometimes used by the commensal fish Careproctus to hold its eggs.
Viviparidae, sometimes known as the river snails or mystery snails, are a family of large operculate freshwater snails, aquatic gastropod mollusks.
The Puget Sound king crab, is a species of king crab which inhabits the oceans of the Pacific coast of North America from Alaska to central California. Adults are orange, red and purple in color, while juveniles are either mostly orange or have small blotches of red and purple. They can be recognized by their blunt bumps on their carapace. Puget Sound king crabs are larger than the similar brown box crab, with an average size of 6–10 inches (15–25 cm).
Assiminea is a genus of minute, salt-tolerant snails with an operculum, aquatic gastropod mollusks, or micromollusks, in the family Assimineidae.
Rhinolithodes wosnessenskii, also called the rhinoceros crab or golf-ball crab, is a species of king crab, the only species in the genus Rhinolithodes. The species is named after Ilya Gavrilovich Voznesenski. It is found at depths of 6–73 metres (20–240 ft) in the north-east Pacific Ocean from Kodiak, Alaska to Crescent City, California.
Turbo is a genus of large sea snails with gills and an operculum, marine gastropod molluscs in the family Turbinidae, the turban snails.
Pomatiopsidae is a family of small, mainly freshwater snails, that have gills and an operculum, aquatic gastropod mollusks in the superfamily Truncatelloidea.
Paralithodes platypus, the blue king crab, is a species of king crab from cold waters in the North Pacific Ocean and adjacent seas. Although blue king crabs are among the largest crabs in the world and reputedly may exceed 18 pounds (8.2 kg) in weight, they are generally smaller than red king crabs.
Hapalogastridae is a family of decapod crustaceans, belonging to king crabs in the broadest sense, containing the following species:
Vitularia is a genus of sea snails, marine gastropod mollusks in the family Muricidae, the murex snails or rock snails.
Hyas is a genus of oregoniid crabs.
Brotia is a genus of Southeast Asian freshwater snails, gastropod molluscs in the taxonomic family Pachychilidae.
Cryptolithodes typicus, often referred to as the butterfly crab or the turtle crab, is a species of lithodid crustacean native to coastal regions of the northeastern Pacific Ocean, ranging from Amchitka Island, Alaska to Santa Rosa Island, California.
Cryptolithodes is a genus of king crabs, containing the following three species:
Paralithodes is a genus of king crabs native to cold waters in the North Pacific Ocean, Okhotsk Sea, Bering Sea and Sea of Japan, but with one species also introduced to far northern Europe. They are medium-large to very large king crabs, and some species are important to commercial fisheries.
Iravadia is a genus of very small, somewhat amphibious land snails that have a gill and an operculum, semi-terrestrial gastropod mollusks or micromollusk in the family Iravadiidae.
The horsehair crab, Erimacrus isenbeckii, is a species of crab which is found mainly in the Northwest Pacific, around the Hokkaido coast in the Sea of Okhotsk and the Western Bering Sea and is an important commercial species used in Japanese cuisine. Despite the importance of the species, biological studies are usually specialized and limited. The catch for the species reached a peak in the 1950s at 27,000 tons and has decreased since, reaching 2,000 tons in 2003. Due to the commercial importance of the species, many stock enhancement programs have been utilized to help maintain a successful fishery. The species is commonly found on sandy benthic environments from shallow water to depths of up to 350 meters.
Phyllolithodes is a monospecific genus of king crab in the family Lithodidae. Its only species, Phyllolithodes papillosus, lives in the intertidal zone and the subtidal zone. It can be found as far north as Unalaska in the Aleutian Islands and as far south as San Miguel Island in Southern California.
