Produced by the Population Genetics and Evolution class, Furman University

The Silurian: Proscorpius
Proscorpius osborni is one of the oldest, most abundant, and most well-studied fossil scorpions. Like other primitive scorpions and the eurypterids from which they evolved, Proscorpius was aquatic; its habitat could be described as “marginal marine, brackish, and fresh water” (Kazlev 2002). It appears to have gills that contained respiratory laminae (Kazlev 2002), instead of book lungs or tracheae found in terrestrial arachnids and extinct trigonotarbids. Proscorpius had a mouth located on the underside of its body, similar to the modern horseshoe crab (Wikipedia 2010), but it was a predator like its scorpion and eurypterid relatives. The classification of Proscorpius is somewhat controversial, as some do not believe it should be classified as a scorpion at all (Dunlop, Tetlie, and Prendini 2008). Even what are generally accepted as gills are not definitive for some critics (Dunlop, Tetlie, and Prendini 2008). Classification issues aside, it is generally recognized as an aquatic organism; terrestrial scorpions would not show up until later, during the Devonian period (Wikipedia 2010).

Page by Lin Lin Zhao
Fossil of Proscorpius osborni, an aquatic Silurian scorpion. Photo Credit: Langheinrich Museum of Paleontology.

Dunlop JA, Tetlie OE, Prendini L. 2008. Reinterpretation of the Silurian scorpion Proscorpius osborni (Whitfield): integrating data from Palaeozoic and recent scorpions. Palaeontology 51: 303-320.

Kazlev MA. 2002. Scorpionida. www.palaeos.com. Accessed February 16, 2010.

Wikipedia. 2010. Chelicerata. Accessed February 16, 2010.