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...)

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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.

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... that the shrimp Periclimenes dardanicola lives on sea anemones on the shell of the hermit crab Dardanus pedunculatus (pictured), in one of the few associations between two decapods?
... that Canada's Federated Co-operatives partnered with SeaChoice to promote sustainable seafood, like the spiny lobster, through its co-operatives?
... that sponge crabs of the species Dromia dormia carry sponges on their back as camouflage, and have even used the sole of a shoe for that purpose?
... that the fairy shrimp Branchinecta gaini is the largest freshwater invertebrate in Antarctica?

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Henri Milne-Edwards (Bruges, October 23, 1800 – Paris, July 29, 1885) was an eminent French zoologist. He was the 27th child of an English father (Wiliam Edwards) and a French mother (Elisabeth Vaux). Henri was born in Bruges, now in Belgium, but then part of the French Republic, and he spent most of his life in France. Henri was brought up in Paris by his older brother William Edwards, a physiologist. After studying medicine in Paris, his passion for natural history prevailed, and he studied the "lower forms" of animal life. He studied under Georges Cuvier and befriended Jean Victoire Audouin. In 1832, Milne-Edwards became professor of hygiene and natural history at the Collège Central des Arts et Manufactures. In 1841, after the death of Audouin, Milne-Edwards succeeded him at the chair of entomology at the Muséum National d'Histoire Naturelle. In 1862, he succeeded Isidore Geoffroy Saint-Hilaire in the long-vacant chair of zoology.

Much of his original work was published in the Annales des sciences naturelles, which he edited from 1834. His Histoire naturelle des Crustacés (1837–1841), long remained a standard work; other works include Histoire naturelle des coralliaires (1858–1860), Leçons sur la physiologie et l'anatomie comparée de l'homme et des animaux (1857–1881), and a work on the elements of zoology, originally published in 1834, but subsequently remodelled, which enjoyed an enormous circulation.

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Lithodes santolla (Decapoda: Lithodidae)

Credit: Butterfly voyages

Lithodes santolla, the southern king crab or centolla is a South American species of king crab.

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General images

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

Image 1Daphnia pulex (Cladocera: Daphniidae) (from Branchiopoda)
Image 2Artemia salina (Anostraca: Artemiidae) (from Branchiopoda)
Image 3Leptostraca such as Nebalia bipes retain the primitive condition of having seven abdominal segments. (from Malacostraca)
Image 4Ostracod swimming motions (in real time) (from Ostracod)
Image 5Copepods, from Ernst Haeckel's 1904 work Kunstformen der Natur (from Crustacean)
Image 6Eryma mandelslohi, a fossil decapod from the Jurassic of Bissingen an der Teck, Germany
Image 7Cancer pagurus (Eucarida: Decapoda) (from Malacostraca)
Image 8Diagram of the maxillule, maxilla and maxilliped of nectiopodan remipedes. (from Remipedia)
Image 9A shed carapace of a lady crab, part of the hard exoskeleton
Image 10Body structure of a typical crustacean – krill (from Crustacean)
Image 11Grapsus grapsus, a terrestrial crab (from Malacostraca)
Image 12Norway lobsters on sale at a Spanish market
Image 13Decapods, from Ernst Haeckel's 1904 work Kunstformen der Natur (from Crustacean)
Image 14Eggs of Potamon fluviatile, a freshwater crab
Image 15Abludomelita obtusata, an amphipod (from Crustacean)
Image 16Porcellio scaber and Oniscus asellus (Peracarida: Isopoda) (from Malacostraca)
Image 17Zoea larva of the European lobster, Homarus gammarus
Image 18Squilla empusa,
a mantis shrimp (from Malacostraca)
Image 19Anatomy of Cypridina mediterranea (from Ostracod)
Image 20Odontodactylus scyllarus (Hoplocarida: Stomatopoda) (from Malacostraca)
Image 21Diagram of the venom apparatus of nectiopodan remipedes. (from Remipedia)
Image 22Diagram of the right mandible of a nectiopodan remipede. (from Remipedia)
Image 23The large ostracod Herrmannina from the Silurian (Ludlow) Soeginina Beds (Paadla Formation) on eastern Saaremaa Island, Estonia (from Ostracod)
Image 24Diagram of the posterior part of the nectiopodan trunk. (from Remipedia)
Image 25Diagram of the ventral side of the head of nectiopodans (from Remipedia)
Image 26Articulated ostracod valves in cross-section from the Permian of central Texas; typical thin section view of an ostracod fossil (from Ostracod)
Image 27Ostracod (from Ostracod)