The Crustaceans Portal

Abludomelita obtusata, an amphipod

Crustaceans (Crustacea /krʌˈstʃə/) form a large, diverse arthropod taxon which includes such animals as crabs, lobsters, crayfish, shrimp, krill, prawns, woodlice, barnacles, copepods, amphipods and mantis shrimp. The crustacean group can be treated as a subphylum under the clade Mandibulata; because of recent molecular studies it is now well accepted that the crustacean group is paraphyletic, and comprises all animals in the clade Pancrustacea other than hexapods. Some crustaceans (Remipedia, Cephalocarida, Malacostraca) are more closely related to insects and the other hexapods than they are to certain other crustaceans.

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), 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 produced by fishery or farming for human consumption, most of it being 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

Illustration of "Cancer capensis" from J. F. W. Herbst's 1792 Versuch einer Naturgeschichte der Krabben und Krebse.
The Cape lobster, Homarinus capensis, is a species of small lobster that lives off the coast of South Africa, from Dassen Island to Haga Haga. Only a few dozen specimens are known, mostly regurgitated by reef-dwelling fish. It lives in rocky reefs, and is thought to lay large eggs that have a short larval phase, or that hatch directly as a juvenile. The species grows to a total length of 10 cm (3.9 in), and resembles a small European or American lobster; it was previously included in the same genus, Homarus, although it is not very closely related to those species, and is now considered to form a separate, monotypic genus – Homarinus. Its closest relatives are the genera Thymops and Thymopides.

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An orange-red lobster-like animal with no claws, seen from the side.

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

Triops longicaudatus (Branchiopoda: Anostraca)
Cscr-featured.svg Credit: Micha L. Rieser

Triops longicaudatus (left: dorsal; right: ventral) is a species of tadpole shrimp which has existed since the Triassic.

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

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