Pseudoscorpionida

Common names: pseudoscorpions

Probability of encounter: high

Quarantine importance: no known importance, but pseudoscorpions are predators capable of achieving high population densities and could be of conservation concern.

Similarity to mites: small size, chelicerae, and mite-like build.  Pseudoscorpions range from 0.5 - 10 mm in length, tend to be dorsoventrally flattened, and are cryptic in coloration. Their scorpion-like pedipalps may be short and massive or elongated into slender forceps.  Opisthosomas are clearly segmented.

 

Morphology

Normal adult length: <10 mm
Body tagmata: prosoma and opisthosoma broadly fused
Eyes: 0-2 pairs of lateral ocelli
Antennae: absent
Mouthparts: 2-segmented, pincer-like chelicerae with elaborate structures (serrula and flagellum) on movable digit and usually 1(rarely 3-4) submedian or subdistal hair; scorpion-like palps
Legs: 4 pairs; all legs used in walking
Distinguishing features: scorpion-like pedipalps, ventral embryo sac, serrula & flagellum on cheliceral digit; endocephalothracic silk system leading to pore on movable cheliceral digit

 

Diversity: >2000 spp.

References

Harvey, MS. 1985. Pseudoscorpionida. pp. 126-155, in BY Main (ed) Zoological Catalogue of Australia #3.

Harvey, MS.  1991.  Catalogue of the Pseudoscorpionida.  Manchester University Press: Manchester.

Harvey, MS. 1992. The phylogeny and classification of the Pseudoscorpionida (Chelicerata: Arachnida). Invertebrate Taxonomy 6: 1373-435.

Muchmore, WB. 1990. Pseudoscorpionida. pp. 503-527, in DL Dindal (ed) Soil Biology Guide. John Wiley & Sons: Brisbane.

Weygoldt, P. 1969. The biology of pseudoscorpions. Harvard University Press: Cambridge.