Pseudoscorpionidae: false scorpions

Synsphyronus niger Synsphyronus absitus

Characteristics
As their name suggests these animals resemble scorpions in many ways and although are in the same Class (Arachnida) are not closely related. They are generally less than 1 centimetre in length and unlike scorpions are harmless. They have 8 legs like other arachnids and can be distinguished from scorpions by the following features:

• Abdomen broadly rounded and lacks a stinging tail

• Silk is spun from their chelicerae

• Pincer-like appendages with venom glands in most species

Many pseudoscorpions have a symbiotic relationship with invertebrates where by they cling to a larger insect and are transported from one area to another.

Life Cycle
Like scorpions, some male species of pseudoscorpion grasp the pedipalps of a female to manoeuvre her over a sperm packet that has been placed onto the substrate. Other species deposit a sperm packet among leaf litter or on the underside of a rock for the female to find and take into her genital opening. The female will then lay her eggs in a brood-sac that remains attached to her genital opening in which the embryos are nourished. After hatching the juvenile pseudoscorpions resemble small adults and will moult 3 times before reaching maturity.

Feeding
Pseudoscorpions are predators and feed on other small invertebrates. They subdue their prey be grasping them with their pincer-like claws and inject them with venom from glands located in the ends of these claws. They then chew a hole into the animal and digest the prey preorally.

Habitat
Pseudoscorpions are common in many terrestrial habitats and are usually found under leaf litter, in moss, under stones and under the bark of trees. The flattened body shape of these animals allows them to conceal themselves in very narrow cracks and crevices. The species Synsphyronus absitus, shown below was found under the bark of a Eucalyptus tree, Eucalyptus microtheca in South Australia.