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Crustaceans (Crustacea /krʌˈsteɪʃə/) form a very muckle group o arthropods thit includes sic weel-kent animals as crabs, lapsters, crayfish, shrimp, croy, slaters an claiks[1]. Crustaceans can be treatit as a subphylum o the clade Mandibulata; acause o recent resairch intae thair molcular upmak, it is nou weel-acceptit thit the group Crustacea is paraphyletic, an maks up aa animals o the clade Pancrustacea, exceptin o hexapods[2].

Alike ither arthropods, crustaceans hae an exoskelet thit thay mout for tae growe. Thay differ frae ither kynds o arthropod, sic as insects an aracnids, acause o thair larval forms an thit thay hae limbs o twa pairts.

Maist crustaceans is free-leevin aquatic animals, but sum is grun-leevin (e.g. slaters), sum is parasites an ithers is sessile, meanin that thay cannae muive independentlie (e.g. claiks). Curstaceans is fand in the fossil record as earlie as the Cambrian period, and incluides leevin fossils like the Podle-Screw o Caerlaverock[3]. thit haes bidit athoot ony real chynge syne the Triassic period. Athort the warld, mair nor 7.9 million tons o crustaceans is producit bi the fishin an marine fairmin industries ilka year[4]. Croy an copepods arnae uised bi fisheries as braildy, but thay micht be the animals wi the greatest biomass on the yird, an is fundamental tae the fuid chain. The studie o crustaceans is kent as carcinologie (forby, malacostracologie, crustaceologie or crustalogie), an a scientist thit studies carcinologie is a carcinologist.

References[eedit | eedit soorce]

  1. Calman, William Thomas (1911). Encyclopædia Britannica (11th ed.). Cambridge University Press. p. 552.
  2. Rota-Stabelli, Omar; Kayal, Ehsan; Gleeson, Dianne; Daub, Jennifer; Boore, Jeffrey L.; Telford, Maximilian J.; Pisani, Davide; Blaxter, Mark; Lavrov, Dennis V. (12 Julie 2010). "Ecdysozoan mitogenomics: evidence for a common origin of the legged invertebrates, the Panarthropoda". Genome Biology and Evolution. 2: 425–440. doi:10.1093/gbe/evq030. ISSN 1759-6653. PMC 2998192. PMID 20624745.
  3. Sample, Ian (29 July 2010). ""World's most ancient creatures found in Scottish field"". The Guardian. Retrieved 15/03/2021. Check date values in: |access-date= (help)
  4. "The State of World Fisheries and Aquaculture 2018, Meeting the Sustainable Development Goals" (PDF). Food and Agriculture Organization of the United Nations.