order of arachnids

A pseudoscorpion (or book scorpion) is an arachnid. They can be 2 to 8 millimetres (0.079 to 0.315 in) long.[1] The largest known species is Garypus titanius of Ascension Island at 12 millimetres (0.47 in).[2][3]

Pseudoscorpions (false scorpions)
Temporal range: Devonian 380 mya
to Recent
Scientific classification

Haeckel, 1866
A book scorpion (Chelifer cancroides) on top of an open book

Pseudoscorpions eat clothes moth larvae, carpet beetle larvae, booklice, ants, mites, and small flies. Because of this, they are liked by humans. The pseudoscorpions are small and cannot harm humans. They are rarely seen because of their size. Some species of pseudoscorpions do a "mating dance" to attract mates.[4] The eggs will stay with the mother until the pseudoscorpions are about a month old.[5] There are more than 3,300 species of pseudoscorpions recorded.[6][7] The oldest known fossil of pseudoscorpions dates back 380 million years to the Devonian period.


  1. Pennsylvania State University, Department: Entomological Notes: Pseudoscorpion Fact Sheet
  2. "Endemic invertebrates" (PDF). Ascension Island Conservation Centre. Archived from the original (PDF) on 2010-05-09. Retrieved 2012-06-08.
  3. "Pseudoscorpions". Agricultural Research Council (South Africa). Archived from the original on 2012-02-22. Retrieved 2012-06-08.
  4. Peter Weygoldt (1966). "Spermatophore web formation in a pseudoscorpion". Science. 153 (3744): 1647–1649. Bibcode:1966Sci...153.1647W. doi:10.1126/science.153.3744.1647. PMID 17802636. S2CID 32393067.
  5. Heather C. Proctor (1993). "Mating biology resolves trichotomy for cheliferoid pseudoscorpions (Pseudoscorpionida, Cheliferoidea)" (PDF). Journal of Arachnology. 21 (2): 156–158.
  6. William A. Shear, Wolfgang Schawaller & Patricia M. Bonamo (1989). "Record of Palaeozoic pseudoscorpions". Nature. 342 (6242): 527–529. Bibcode:1989Natur.341..527S. doi:10.1038/341527a0. S2CID 4324620.
  7. Wolfgang Schawaller, William A. Shear & Patricia M. Bonamo (1991). "The first Paleozoic pseudoscorpions (Arachnida, Pseudoscorpionida)". American Museum Novitates (3009).

Further reading

  • Harvey M.S. 2011. Pseudoscorpions of the World, version 2.0. Western Australian Museum, Perth. Pseudoscorpions of the World
  • Joseph C. Chamberlin 1931. The Arachnid Order Chelonethida. Stanford University Publications in Biological Science. 7(1): 1–284.
  • W.B. Muchmore 1982. Pseudoscorpionida. In Synopsis and classification of living organisms. Vol 2, Parker, S.P.