Chelicerata (Arachnids, Including Spiders, Mites and Scorpions)


Chelicerata is the group of arthropods that includes the marine sea‐spiders and horseshoe crabs and the terrestrial arachnids (spiders, mites, scorpions and their relatives). They have two main body regions, and the arachnids typically have eight walking legs. They are covered by a jointed exoskeleton and grow by periodic moulting. Chelicerates are typically predaceous and most terrestrial forms ingest only liquefied food. Next to insects, they are the most diverse and numerous animals.

Keywords: arthropoda; pycnogonida; xiphosura; eurypterida; arachnida

Figure 1.

Two living chelicerates, the Atlantic horseshoe crab (Limulus polyphemus: Xiphosura) and the giant whipscorpion (Mastigoproctus giganteus: Arachnida, Thelyphonida). Dorsal perspectives.

Figure 2.

A diagrammatic sagittal section of a spider showing the major internal organs.


Further Reading

Bonaventura J, Bonaventura C and Tesh S (eds) (1982) Physiology and Biology of Horseshoe Crabs: Studies on Normal and Environmentally Stressed Animals. New York: A.R. Liss.

Foelix RF (1997) Biology of Spiders, 2nd edn. London: Oxford University Press.

King PE (1973) Pycnogonids. London: Hutchinson.

Polis GA (ed.) (1990) The Biology of Scorpions. Stanford: Stanford University Press.

Ruppert EE and Barnes RF (1994) Invertebrate Zoology, 6th edn. Philadelphia: Saunders College.

Savory T (1964) Arachnida. London: Academic Press.

Selden PA (1993) Arthropoda (Aglaspidida, Pycnogonida and Chelicerata). In: Benton MJ (ed.) The Fossil Record 2,, pp. 297–320. London: Chapman and Hall.

Shultz JW (1990) Evolutionary morphology and phylogeny of Arachnida. Cladistics 6: 1–38.

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How to Cite close
Shultz, Jeffrey W(May 2001) Chelicerata (Arachnids, Including Spiders, Mites and Scorpions). In: eLS. John Wiley & Sons Ltd, Chichester. [doi: 10.1038/npg.els.0001605]