Portal:Crustaceans

The Crustaceans Portal

Crustaceans (from Latin word "crustacea" meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of arthropods that are traditionally a part of the subphylum Crustacea (/krəˈsteɪʃə/), a large, diverse group of mainly aquatic arthropods including the more familiar decapods (shrimps, prawns, crabs, lobsters and crayfish), seed shrimps, 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 pan-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...)

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The Cape lobster, Homarinus capensis, is a species of small lobster that lives off the coast of South Africa, from Dassen Island to Haga Haga. Only a few dozen specimens are known, mostly regurgitated by reef-dwelling fish. It lives in rocky reefs, and is thought to lay large eggs that have a short larval phase, or that hatch directly as a juvenile. The species grows to a total length of 10 cm (3.9 in), and resembles a small European or American lobster; it was previously included in the same genus, Homarus, although it is not very closely related to those species, and is now considered to form a separate, monotypic genus – Homarinus. Its closest relatives are the genera Thymops and Thymopides.

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... that Pollicipes pollicipes (pictured), a goose barnacle found on rocky shores in the north-east Atlantic Ocean, is a delicacy in Spain where it may fetch up to €90 per kilogram?
... that beta males of Paracerceis sculpta mimic females and gamma males mimic juveniles, allowing them to mate without the alpha males realising?
... that Branchinecta lynchi, a vulnerable species of fairy shrimp, can be found in vernal pools around Agate Lake?
... that sea lice flourishing on salmon farms can spread to nearby wild salmon and devastate their stocks?

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Charles Chilton (1860–1929) was a New Zealand zoologist, the first rector to be appointed in Australasia, and the first person to be awarded a D.Sc. degree in New Zealand.

Chilton was born on September 27, 1860 at Little Marstone, Pencombe (near Leominster, Herefordshire, England) but emigrated with his family to New Zealand in 1862. They settled on a farm at East Eyreton, North Canterbury. He was troubled by his hips from an early age, and had his left leg amputated, using an artificial leg and a crutch thereafter. In 1881, he gained an M.A. with first class honours from Canterbury College, having been taught by Frederick Wollaston Hutton, who inspired him to take up biology, especially the study of crustaceans, which had been little studied in New Zealand up to that time.

Chilton's first scientific publication followed that same year, when he described three new species of crustacean (two crabs and one isopod) from Lyttelton Harbour and Lake Pupuke. He surprised the scientific world later that year by describing four species of amphipod and isopod from groundwaters at the family farm in Eyreton. He went on to discover the isopod Phreatoicus typicus in the same location, the first example ever described of the suborder Phreatoicidea, the "earliest derived isopod[s]".

Charles Chilton became rector of Christchurch University College in 1921, the first time such a post had been granted in Australia or New Zealand. Chilton died on October 25, 1929 of a sudden attack of pneumonia, before he could collect his life's work into a single monograph. He had published 130 papers on crustaceans, mostly amphipods, isopods and decapods, from all around the world, but especially from New Zealand, subterranean and sub-Antarctic waters.

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Credit: LiquidGhoul

Soldier crabs of the genus Mictyris, including M. longicarpus (pictured) congregate at low tide to feed by filtering mud. As the tide rises, they bury themselves, digging in a corkscrew pattern.

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General images

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

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