Pseudoscorpions (also known as False Scorpions or book scorpions) are not actually scorpions at all but are a type of arachnid. They belong to the same class of animals as spiders – the arachnida; and are known as pseudo-scorpions as they look exactly like scorpions but without the stinging tail.
Latin name: Microbisium brevifemoratum
Notable feature: They look exactly like scorpions but without the stinging tail
Rarity in the UK: Rare / Common
There are currently 27 species of pseuodscorpion known to be living in the UK and around 12 of these species are quite common. You are unlikely to see a pseudoscorpion unless you’re actively looking for one as they are quite small ranging from between 2 – 8mm depending on the species. Some have two, four or even no eyes at all and can vary in colour from pale yellow to dark brown.
No sting to its tail?
These small arachnids have a flat, pear shaped body that is protected by armoured plates, but unlike scorpions that possess a stinging tail, their abdomen is short and rounded at the rear. Don’t let this fool you though; all pseudoscorpions have two long pincers (known as pedipalps) equipped with cutting teeth which they use to catch and inject venom into its prey. The venom serves to paralyse the pray, such as tiny springtails or mites, and a fluid is then poured over the victim to digest it and the liquid meal is ready to be eaten!
Where to find a pseudoscorpion
Pseudoscorpions can be found in a variety of habitats including leaf litter, decaying vegetation and beneath tree bark in woodland, heathland, grassland, along the sea shore, sand dunes, on salt marshes, in bird and mammal nests, and even in our homes!
The eating habits of the pseudoscorpion can have its benefits to ‘us humans’ as they prey on clothes moth larvae, carpet beetle larvae, ants, mites, small flies and booklice. Chelifer cancroides is the species most commonly found in homes, where they are often found in rooms with dusty books. These tiny animals (2.5–4.5 mm) can find their food like booklice and house dust mites and can enter homes by hitching a ride with larger insects such as flies and beetles. Pseudoscorpions and in this case Cheiridium museorumwere first described by the Greek philosopher Aristotle and were thought to be feeding on booklice that eat glue, leather and cloth of old books, although the oldest known fossil of this group dates back to 380 million years ago!
Pseudo – Romantic
Using a gland in their jaws pseudoscorpions can make disc shaped cocoons which can be used for mating, moulting or to provide shelter in cold weather. The males of some pseudoscorpion species use an elaborate mating dance by tapping their legs and abdomens to ensure that the eggs of the female become fertilised. The female will make a nest from silk and debris and will lay between 2 and 50 eggs into a brood pouch under her abdomen. Pseudoscorpions moult several times before they reach adulthood and once they reach this stage can live up to three years.
Discover a new species!
There are known to be 27 species of pseudoscorpion in the UK however it is highly likely that new species are present and waiting to be discovered! If you do have any records of pseudoscorpions please contact the Pseudoscorpion Recorders Group and help to improve and share knowledge about this fascinating group of arachnids!