Portal:Crustaceans

The Crustaceans Portal

Crustaceans (from Latin 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 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 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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Nephrops norvegicus, known variously as the Norway lobster, Dublin Bay prawn, langoustine (compare langostino) or scampi, is a slim, orange-pink lobster which grows up to 25 cm (10 in) long, and is "the most important commercial crustacean in Europe". It is now the only extant species in the genus Nephrops, after several other species were moved to the closely related genus Metanephrops. It lives in the north-eastern Atlantic Ocean, and parts of the Mediterranean Sea, but is absent from the Baltic Sea and Black Sea. Adults emerge from their burrows at night to feed on worms and fish.

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Did you know?

... that although the Pacific sand crab can only crawl and burrow backwards (pictured), it can also tread water?
... that Praunus flexuosus, the first mysid shrimp ever to be described, may have been transported to North America during World War II?
... that Calcinus tubularis is one of only two known species of hermit crab whose males and females inhabit different types of shell?
... that Petrolisthes eriomerus, when trying to escape from a predator, can cast off limbs as a diversion, with the claws of a cast limb still gripping vigorously after separation?

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Pierre André Latreille (November 20, 1762 – February 6, 1833) was a French zoologist, specialising in arthropods. Latreille was born illegitimately on November 29, 1762 in the town of Brive, then in the province of Limousin. Having trained as a Roman Catholic priest before the French Revolution, Latreille was imprisoned after the Civil Constitution of the Clergy, and only regained his freedom after recognising a rare species he found in the prison, Necrobia ruficollis.

He published his first important work in 1796 (Précis des caractères génériques des insectes), and was eventually employed by the Muséum National d'Histoire Naturelle. His foresighted work on arthropod systematics and taxonomy, using all available characters and rejecting anthropocentrism and teleology, gained him respect and accolades. He was considered the foremost entomologist of his time, and was described by one of his pupils as "the prince of entomologists". He helped found the Société entomologique de France, acting as honorary president, and was honoured by having dozens of species and genera named after him.

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Credit: Gideon Pisanty

Ocypode cursor is a species of ghost crab that lives on sandy beaches in the Atlantic Ocean and Mediterranean Sea.

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General images

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

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