Portal:Crustaceans

Portal topics: Activities; Culture; Geography; Health; History; Mathematics; Nature; People; Philosophy; Religion; Society; Technology; Random portal

The Crustaceans Portal

Crustaceans are a group of arthropods that are a part of the subphylum Crustacea (/krəˈsteɪʃə/), a large, diverse group of mainly aquatic arthropods including decapods (shrimps, prawns, crabs, lobsters and crayfish), seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, opossum shrimps, amphipods and mantis shrimp. The crustacean group can be treated as a subphylum under the clade Mandibulata. It is now well accepted that the hexapods (insects and entognathans) emerged deep in the Crustacean group, with the completed group referred to as Pancrustacea. The three classes Cephalocarida, Branchiopoda and Remipedia are more closely related to the hexapods than they are to any of the other crustaceans (oligostracans and multicrustaceans).

The 67,000 described species range in size from Stygotantulus stocki at 0.1 mm (0.004 in), to the Japanese spider crab with a leg span of up to 3.8 m (12.5 ft) and a mass of 20 kg (44 lb). Like other arthropods, crustaceans have an exoskeleton, which they moult to grow. They are distinguished from other groups of arthropods, such as insects, myriapods and chelicerates, by the possession of biramous (two-parted) limbs, and by their larval forms, such as the nauplius stage of branchiopods and copepods.

Most crustaceans are free-living aquatic animals, but some are terrestrial (e.g. woodlice, sandhoppers), some are parasitic (e.g. Rhizocephala, fish lice, tongue worms) and some are sessile (e.g. barnacles). The group has an extensive fossil record, reaching back to the Cambrian. More than 7.9 million tons of crustaceans per year are harvested by fishery or farming for human consumption, consisting mostly of shrimp and prawns. Krill and copepods are not as widely fished, but may be the animals with the greatest biomass on the planet, and form a vital part of the food chain. The scientific study of crustaceans is known as carcinology (alternatively, malacostracology, crustaceology or crustalogy), and a scientist who works in carcinology is a carcinologist. (Full article...)

Refresh with new selections below (purge)

Selected article

The coconut crab, Birgus latro, is a species of terrestrial hermit crab, also known as the "robber crab" or "palm thief". It is the largest land-living arthropod in the world, and is probably at the upper size limit of terrestrial animals with exoskeletons in today's atmosphere at a weight of up to 4.1 kg (9.0 lb). It is found on islands across the Indian Ocean and parts of the Pacific Ocean as far east as the Gambier Islands, mirroring the distribution of the coconut palm. Adults develop a tough exoskeleton on their abdomen and stop carrying a shell. They cannot swim, and will drown if immersed in water for long. Sexual maturity is reached after about 5 years, and the total lifespan may be over 60 years.

Adult coconut crabs feed on fruits, nuts, seeds, and the pith of fallen trees, but will eat carrion and other organic matter opportunistically. The species is popularly associated with the coconut, and has been widely reported to climb trees to pick coconuts, which it then opens to eat the flesh. While coconut crabs can climb trees, and can eventually open a coconut collectively, coconuts are not a significant part of their diet. Coconut crabs are hunted wherever they come into contact with humans, and are subject to legal protection in some areas. In the absence of precise information, the IUCN lists the species as Data Deficient.

Read more...

More selected articles

Did you know?

... that until the discovery in 1975 of the "living fossil" Neoglyphea inopinata (pictured), glypheoid crustaceans were thought to have been extinct since the Eocene?
... that the goose barnacle Lepas anserifera is found attached to driftwood, flotsam and even whales?
... that the spiny lobster Jasus caveorum lives only on one of the Foundation Seamounts in the southern Pacific Ocean?
... that the Cape Verdean spiny lobster Palinurus charlestoni is named after a French fishing boat?

More Did you know facts

Selected biography

Robert Gurney (July 31, 1879 – March 5, 1950) was a British zoologist most famous for his monographs on British Freshwater Copepoda (1931–1933) and the Larvae of Decapod Crustacea (1942). He was born in 1879 as the fourth son of John Gurney and Isabel Charlotte Gurney (later Baroness Talbot de Malahide) of Sprowston Hall, Norfolk. He went to school at Eton College, and went on to study at New College, Oxford, graduating with first class honours in 1902. He was never associated with any institution, but worked from his home, initially in Norfolk, but later at Boars Hill. Realising the need for a specialist field station for freshwater biology to match the marine biological stations at Plymouth and Naples, Robert and his brother Eustace set up Great Britain's first freshwater laboratory at Sutton Broad. Gurney's two great study objects were the Copepoda and the larvae of Decapoda (zoea larva of Homarus gammarus pictured), and his greatest works were the three-volume monograph British Freshwater Copepoda, published by the Ray Society in 1931–1933, and his Larvae of Decapod Crustacea published by the Ray Society in 1942. Gurney travelled to North Africa and Bermuda, and received material from other foreign expeditions, including the Terra Nova Expedition (1910–1913) and the Discovery Investigations of the 1920s and 1930s.

Read more...

More selected biographies

Selected image

Credit: Kevin Cole

The Dungeness crab, Metacarcinus magister (formerly Cancer magister), is a species of crab that inhabits East Pacific eelgrass beds and water bottoms from Alaska's Aleutian Islands to Santa Cruz, California.

Read more...

More selected pictures

General images

The following are images from various crustacean-related articles on Wikipedia.

Image 1Cancer pagurus (Eucarida: Decapoda) (from Malacostraca)
Image 2Eryma mandelslohi, a fossil decapod from the Jurassic of Bissingen an der Teck, Germany
Image 3Ostracod (from Ostracod)
Image 4Odontodactylus scyllarus (Hoplocarida: Stomatopoda) (from Malacostraca)
Image 5Copepods, from Ernst Haeckel's 1904 work Kunstformen der Natur (from Crustacean)
Image 6Ostracod swimming motions (in real time) (from Ostracod)
Image 7Artemia salina (Anostraca: Artemiidae) (from Branchiopoda)
Image 8Abludomelita obtusata, an amphipod (from Crustacean)
Image 9Decapods, from Ernst Haeckel's 1904 work Kunstformen der Natur (from Crustacean)
Image 10The large ostracod Herrmannina from the Silurian (Ludlow) Soeginina Beds (Paadla Formation) on eastern Saaremaa Island, Estonia (from Ostracod)
Image 11Anatomy of Cypridina mediterranea (from Ostracod)
Image 12Grapsus grapsus, a terrestrial crab (from Malacostraca)
Image 13Eggs of Potamon fluviatile, a freshwater crab
Image 14Articulated ostracod valves in cross-section from the Permian of central Texas; typical thin section view of an ostracod fossil (from Ostracod)
Image 15Daphnia pulex (Cladocera: Daphniidae) (from Branchiopoda)
Image 16Squilla empusa,
a mantis shrimp (from Malacostraca)
Image 17Porcellio scaber and Oniscus asellus (Peracarida: Isopoda) (from Malacostraca)
Image 18Body structure of a typical crustacean – krill (from Crustacean)
Image 19A shed carapace of a lady crab, part of the hard exoskeleton
Image 20Norway lobsters on sale at a Spanish market
Image 21Leptostraca such as Nebalia bipes retain the primitive condition of having seven abdominal segments. (from Malacostraca)
Image 22Zoea larva of the European lobster, Homarus gammarus