Interesting Animals: Pseudoscorpion

A pseudoscorpion (aka "false scorpion"), showing the pincher-like pedipalps that give the group its name

Pseudoscorpions are arachnids, placing them in the same group as spiders, scorpions, and ticks, mites, daddy-long-legs, many other eight-legged creatures. They are small with a maximum body length of eight millimeters. Like spiders, these arthropods have silk glands, though their glands are near their mouth rather than at the end of their abdomen. Though they are harmless and lack stingers, the "scorpion" part of their name comes from their large, pinching pedipalps much like those seen in scoprions. Pedipalps, or are basically an extra pair of legs used for various purposes in arachnids, including feeding, defense, and reproduction.

The majority of pseudoscoprion species are found in the tropics, but there are also those found in colder climes. Rarely, they can turn up inside of homes. They are most often found in humid areas, so if found in a house they will usually be seen in bathrooms or basements. Since these animals are harmless, if you find one in your home it's recommended you leave them be. However, the best way to get rid of them is to dry out the area they are found.

Pseudoscorpion phoresy on a fly

These creatures are one of several groups known to practice phoresy, which would be more commonly referred to as hitchhiking. Some species of pseudoscorpion will attach themselves to the bodies of other insects so that they can be transported from place to place. One of the few times I've actually seen a pseudoscorpion was when one fell out from under the wing of a captured beetle that it had been riding on. Phoresy is an interaction where one species gains benefit and the other is unharmed and thus is a form of commensalism.

Though there are about two thousand species of pseudoscorpion, they are apparently difficult to identify.

Sources are Penn State, University of Minnesota, Texas A&M, and Michigan State University. Images are from Wikimedia Commons under Creative Commons licenses: one, two.