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...)

Selected article

Cancer pagurus (Malacostraca: Decapoda: Cancridae)

Cancer pagurus, commonly known as the edible crab or brown crab, is a species of crab found in the North Sea, North Atlantic Ocean and perhaps in the Mediterranean Sea. It is a robust crab of a reddish-brown colour, having an oval carapace with a characteristic "pie crust" edge and black tips to the claws. A mature adult may have a carapace width of up to 25 cm (10 in) and weigh up to 3 kg (6.6 lb). C. pagurus is a nocturnal predator, targeting a range of molluscs and crustaceans. It is the subject of the largest crab fishery in Western Europe, centred around the coasts of the British Isles, with more than 60,000 tonnes caught annually.

Did you know?

A small spotted crab on a mangrove leaf. — Aratus pisonii (Decapoda: Sesarmidae)

... that the mangrove tree crab, Aratus pisonii (pictured), prefers animal food but mostly feeds on mangrove leaves?
... that the anemone crab Mithraculus cinctimanus often lives in close association with the sea anemone Lebrunia danae?
... that the barnacle Megatrema anglicum lives semi-parasitically on such corals as the Devonshire cup coral?
... that one of the major prey groups of the paddle crab, Ovalipes catharus, is other paddle crabs?

Selected biography

Michèle de Saint Laurent (December 9, 1926 – July 11, 2003) was a French carcinologist. She was born on December 9, 1926 at Fontainebleau, near Paris. She studied general biology at the University of Paris under Pierre-Paul Grassé, earning her Diplôme de Licence in 1954. She started undertaking scientific research even before finishing her degree, and the resulting paper brought her into contact with staff at the Muséum national d'histoire naturelle in Paris. From 1955 until 1960, she worked at the Centre National de la Recherche Scientifique (CNRS), at their laboratory at Banyuls-sur-Mer; thereafter, she returned to the Paris museum.

The first major focus of Michèle de Saint Laurent's work was the systematics of hermit crabs. She also investigated other decapod crustaceans, particularly the Thalassinidea. As a result of this work, she was invited in 1974 to visit the Smithsonian Institution and was given an unidentified specimen which had been caught by the Albatross expedition in 1908. She and Jacques Forest realised that it represented a living relative of the Glypheoidea, a group previously thought to have been extinct since the Eocene. They described the new genus together in 1975, as Neoglyphea. De Saint Laurent's later work included a new classification of crabs (involving the recognition of a new section, Eubrachyura), and three new superfamilies (Axioidea, Enoplometopoidea and Retroplumoidea), as well as various works on the decapods of hydrothermal vents.

Selected image

Nototropis falcatus (Amphipoda: Atylidae)

Nototropis falcatus (formerly Atylus falcatus) is a species of amphipod from sandy bottoms in the North Atlantic and North Sea.

General images

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

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