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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Potamon fluviatile is a freshwater crab found in or near wooded streams, rivers and lakes in Southern Europe. It is an omnivore with broad ecological tolerances, and adults typically reach 50 mm (2 in) in size during their 10–12 year lifespan. They inhabit burrows and are aggressive, apparently outcompeting native crayfish. P. fluviatile has been harvested for food since Classical antiquity, and is now threatened by overexploitation. Many of the island populations are particularly vulnerable, and the Maltese subspecies has become a conservation icon. A population in Rome is the only population of freshwater crabs to occur in the middle of a large city, and may have been brought there before the founding of the Roman Empire.

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Scyllarides latus (Decapoda: Scyllaridae) by Cornelius Sittardus

... that all that remains of the type specimen of the Mediterranean slipper lobster is a 16th century watercolour (pictured)?
... that the blind crustacean Polycheles typhlops preys on fish and on other crustaceans, probably acting as an ambush predator?
... that Edward J. Miers was paid 60 guineas for his monograph on the crabs of the Challenger expedition?
... that the genus Platythelphusa represents the only evolutionary radiation of crabs to have occurred in a freshwater lake?

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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.

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Credit: Elizabeth Crapo, NOAA Corps

The Sally Lightfoot crab, Grapsus grapsus, sits on volcanic rocks on the Galápagos Islands.

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General images

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

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