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What are scorpions?

Why study scorpions?
Life History
Dwindling Expertise


A fossil scorpion (Palaeophonus sp.) with associated eurypterid fragments

Scorpions enjoy widespread public appeal (much of it based on fear).  Their toxicity, relatively large size, and fearsome appearance, notwithstanding the great age of their lineage, contribute to a fascination that has always and continues to surround them (Cloudsley-Thompson 1990).  Among the most ancient arthropods, derived from amphibious ancestors that lived in the Silurian, more than 400 million years ago, scorpions have earned the title of ‘living fossils’ (Jeram 1990).  The scorpion groundplan, developed so long ago, is highly successful.  Paleozoic scorpions closely resemble their modern descendants in basic anatomical details, except that some were considerably larger (Jeram 1994, 1998).  Brontoscorpio anglicus measured approximately 1 meter in length (Kjellesvig-Waering 1986) — an order of magnitude greater than the largest extant members of Pandinus from tropical Africa, which average about 20 cm in length (Sissom 1990).  Scorpions were formerly considered to be the sister group of all other arachnids because they closely resemble extinct marine eurypterids (the sister group of arachnids).  Recent data, however, suggests that scorpions are embedded in the arachnid lineage, and merely retain primitive features. 

A eurypterid (Eurypteris remipes)

Literature Cited:

Cloudsley-Thompson, J.L. 1990. Scorpions in mythology, folklore, and history. In: Polis, G.A. (Ed.) The Biology of Scorpions. Stanford University Press, Stanford, CA, 462–485.

Jeram, A. 1990. When scorpions ruled the world. New Scientist 126: 52–55.

Jeram, A. 1994. Carboniferous Orthosterni and their relationship to living scorpions. Palaeontology 37: 513–550.

Jeram, A.J. 1998. Phylogeny, classification and evolution of Silurian and Devonian scorpions. In: Selden, P.A. (Ed.) Proceedings of the 17th European Colloquium of Arachnology, Edinburgh 1997. British Arachnological Society, Burnham Beeches, Buckinghamshire, UK, 17–31.

Kjellesvig-Waering, E.N. 1986. A restudy of the fossil Scorpionida of the world. (Palaeontographica Americana 55: 1–287). Organized for publication by A.S. Caster & K.E. Caster. Ithaca, New York.

Sissom, W.D. 1990. Systematics, biogeography and paleontology. In: Polis, G.A. (Ed.) The Biology of Scorpions. Stanford University Press, Stanford, CA, 64–160.



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