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

Neotrypaea californiensis (formerly Callianassa californiensis), known as the Bay ghost shrimp, is a species of ghost shrimp that lives on the Pacific coast of North America. It is a pale animal which grows to a length of 11.5 cm (4.5 in). One claw is bigger than the other, especially in males, and the enlarged claw is thought to have a function in mating. N. californiensis is a deposit feeder that lives in extensive burrow systems, and is responsible for high rates of bioturbation. It adversely affects oyster farms, and its numbers are controlled in some places by the application of pesticides. It carries out an important role in the ecosystem, and is used by fishermen as bait.

Read more...

More selected articles

Did you know?

... that the zoea larvae of crabs have long rostral and dorsal spines (pictured)?
... that the spiny lobster Panulirus homarus is one of the main prey items for the Cape clawless otter?
... that the carcinologist Robert Gurney was not connected to a university, and carried out his scientific work at home?
... that cherry-sized soldier crabs of the species Mictyris longicarpus have been described as "cheerful bohemians"?

More Did you know facts

Selected biography

Thomas Bell FRS (October 11, 1792 – March 13, 1880) was an English zoologist, surgeon and writer, born in Poole, Dorset, UK. Bell, like his mother Susan, took a keen interest in natural history which his mother also encouraged in his younger cousin Philip Henry Gosse. Bell left Poole in 1813 for his training as a dental surgeon in London. He combined two careers, becoming Professor of Zoology at King's College London in 1836 (on the strength of his amateur researches) and lecturing on anatomy at Guy's Hospital. He became a Fellow of the Royal College of Surgeons in 1844. He was President of the Linnean Society in 1858. Bell was at the heart of the scientific establishment and when Charles Darwin returned to London from the Beagle expedition on December 2, 1836, Bell was quick to take on the task of describing the reptile specimens. He was also entrusted with the specimens of crustaceans collected on the voyage. He was the authority in this field; his book British Stalked-eye Crustacea is a masterwork.

Read more...

More selected biographies

Selected image

Credit: Elizabeth Crapo, NOAA Corps

The Sally Lightfoot crab, Grapsus grapsus, sits on volcanic rocks on the Galápagos Islands.

Read more...

More selected pictures

General images

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

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