Portal:Crustaceans

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The Crustaceans Portal

Abludomelita obtusata.jpg

Crustaceans (Subphylum Crustacea) form a very large group of arthropods, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 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 14 ft (4.3 m) and a mass of 44 lb (20 kg). Like other arthropods, crustaceans have an exoskeleton, which they moult in order 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 the nauplius form of the larvae. Most crustaceans are free-living aquatic animals, but some are terrestrial (e.g. woodlice), some are parasitic (e.g. fish lice, tongue worms) and some are sessile (e.g. barnacles). The group has an extensive fossil record, reaching back to the Cambrian, and includes living fossils such as Triops cancriformis, which has existed apparently unchanged since the Triassic period. More than 10 million tons of crustaceans are produced by fishery or farming for human consumption, the majority of it being shrimps 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.

Selected article

Hemigrapsus estellinensis is an extinct species of crab, formerly endemic to the Texas Panhandle. It was closely related to species from the Pacific Ocean such as Hemigrapsus oregonensis, but lived 500 mi (800 km) inland in a hypersaline spring. Its occurrence so far from the ocean has been described as "curious", and it was "probably a Pleistocene relic". It differed from its relatives by the pattern of spots on its back, and by the relative sizes of its limbs. H. estellinensis was discovered by Gordon C. Creel in 1962 and was probably already extinct before his description was published in 1964, after the Estelline Salt Springs where it lived were contained by the United States Army to reduce the salt load on the Prairie Dog Town Fork of the Red River.

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Ocypode quadrata (Decapoda: Ocypodidae)

Selected biography

The Reverend Thomas Roscoe Rede Stebbing F.R.S., F.L.S. (February 6, 1835 – July 8, 1926) was a British zoologist, who described himself as "a serf to natural history, principally employed about Crustacea".

Having trained as an evangelical Anglican, Stebbing expected to be a staunch opponent of Charles Darwin's recently published theory of evolution by natural selection. Following a critical review of The Descent of Man in The Times in 1871, Stebbing gained prominence by responding in Nature. Stebbing wrote a number of essays on the topic of Darwinism, in which he dissected the argument posited against it, and questioned various aspects of Christianity. His outspoken stance resulted in his being banned from preaching, and he was never offered a parish by the church.

Most of Stebbing's scientific works, comprising more than 110 papers, covered amphipod crustaceans. Stebbing produced a monograph on the amphipods collected on the 1872–1876 expedition by HMS Challenger. He also produced a monograph of the Cumacea, a natural history of the Crustacea, and a biography of the Scottish naturalist and founder of the University Marine Biological Station, Millport, David Robertson. In 1906, Stebbing published the volume on Gammaridea for the series Das Tierreich.

Selected picture

Grapsus grapsus (Decapoda: Grapsidae)
Cscr-featured.svg Credit: Elizabeth Crapo, NOAA Corps

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

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