Portal:Crustaceans

The Crustaceans Portal

Crustaceans (from Latin word "crustacea" meaning: "those with shells" or "crusted ones") are mandibulate arthropods that are traditionally a part of the paraphyletic subphylum Crustacea (/krəˈsteɪʃə/). Crustaceans are mainly aquatic, including decapods (shrimps, prawns, crabs, lobsters, and crayfish), seed shrimps, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, opossum shrimps, amphipods and mantis shrimp. It is now well accepted that hexapods (insects and entognathans) are cladistically crustaceans, with the two groups now combined in the monophyletic clade Pancrustacea. The three classes Cephalocarida, Branchiopoda, and Remipedia are more closely related to the hexapods than they are to any 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

Carcinus maenas (Malacostraca: Decapoda: Carcinidae)

Carcinus maenas, the shore crab or green crab, is a common littoral crab, and an important invasive species, listed among the 100 "world's worst alien invasive species". Although native to the Baltic Sea, North Sea and north-east Atlantic Ocean, it has since become established on both east and west coasts of North America, in Argentina, South Africa and Australia. C. maenas is a predator feeding on many organisms, particularly bivalve molluscs (such as clams, oysters, and mussels), polychaetes and small crustaceans. It is primarily nocturnal, although activity also depends on the tide, and crabs can be active at any time of day.

Did you know?

Leptodori kindtii (Cladocera: Leptodoridae)

... that Leptodora (pictured) is the largest planktonic cladoceran, and its type species is probably the only cladoceran to have been described in a newspaper?
... that the woodlouse Trichoniscus pusillus has some populations that reproduce sexually and others that reproduce clonally?
... that Hemimysis anomala, a mysid shrimp native to the Ponto-Caspian region, has recently invaded the North American Great Lakes?
... that the New Zealand endemic amphipod Paraleptamphopus caeruleus lives in "bog-water on top of Swampy Hill"?

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.

Selected image

Goose barnacles (order Pedunculata), such as these Lepas anatifera, are filter-feeding crustaceans that live attached to hard surfaces of rocks and flotsam in the intertidal zone.

General images

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

Image 1Diagram of the ventral side of the head of nectiopodans (from Remipedia)
Image 2Grapsus grapsus, a terrestrial crab (from Malacostraca)
Image 3Cancer pagurus (Eucarida: Decapoda) (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 5Body structure of a typical crustacean – krill (from Crustacean)
Image 6Eryma mandelslohi, a fossil decapod from the Jurassic of Bissingen an der Teck, Germany
Image 7Diagram of the maxillule, maxilla and maxilliped of nectiopodan remipedes. (from Remipedia)
Image 8Decapods, from Ernst Haeckel's 1904 work Kunstformen der Natur (from Crustacean)
Image 9Anatomy of Cypridina mediterranea (from Ostracod)
Image 10A shed carapace of a lady crab, part of the hard exoskeleton
Image 11Odontodactylus scyllarus (Hoplocarida: Stomatopoda) (from Malacostraca)
Image 12Norway lobsters on sale at a Spanish market
Image 13Artemia salina (Anostraca: Artemiidae) (from Branchiopoda)
Image 14Daphnia pulex (Cladocera: Daphniidae) (from Branchiopoda)
Image 15Eggs of Potamon fluviatile, a freshwater crab
Image 16Porcellio scaber and Oniscus asellus (Peracarida: Isopoda) (from Malacostraca)
Image 17Zoea larva of the European lobster, Homarus gammarus
Image 18Abludomelita obtusata, an amphipod (from Crustacean)
Image 19The large ostracod Herrmannina from the Silurian (Ludlow) Soeginina Beds (Paadla Formation) on eastern Saaremaa Island, Estonia (from Ostracod)
Image 20Diagram of the posterior part of the nectiopodan trunk. (from Remipedia)
Image 21Copepods, from Ernst Haeckel's 1904 work Kunstformen der Natur (from Crustacean)
Image 22Diagram of the venom apparatus of nectiopodan remipedes. (from Remipedia)
Image 23Leptostraca such as Nebalia bipes retain the primitive condition of having seven abdominal segments. (from Malacostraca)
Image 24Ostracod swimming motions (in real time) (from Ostracod)
Image 25Ostracod (from Ostracod)
Image 26Diagram of the right mandible of a nectiopodan remipede. (from Remipedia)
Image 27Squilla empusa,
a mantis shrimp (from Malacostraca)