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The Seashore

Marine Pseudoscorpion (Neobisium maritimum)

Marine Pseudoscorpion (Neobisium maritimum)

The tiny marine pseudoscorpion photographed on Ulva (not the usual microhabitat)

This is an amazing little terrestrial invertebrate that has adapted to live on the seashore. Length varies from a few millimetres up to half a centimetre. It typically lives amongst the Lichina pygmaea in the upper middle shore and other crevices of rocky shores. Here it predates on any small invertebrates. To catch its prey it uses the chelae (claws). On these are poison glands. Poison is released from a duct at the tip, via a tiny poison tooth which apparently aids in puncturing the exoskeletons of prey. They hang on tight to the prey until it is dead. Then the smaller chelicerae (visible at the tip of the head in the above photo) chew up the prey.

Pseudoscorpions build a silken chamber to house themselves and it is thought that Neobisium maritimum uses this more than most pseudoscorpions. This will give some protection from the elements inside its crevice. When covered by the tide air becomes trapped inside the silk and acts like a "gill". Carbon dioxide will dissolve into the water and oxygen diffuses into the chamber. The silk nest encorporates debris and material from around it, e.g. bits of lichen. Females carrying eggs will take refuge inside the silken chamber, in some cases staying in the tiny home until the eggs have hatched, releasing protonymphs. They also use the silk chamber to protect itself when ecdysing (moulting). Moulting in a silken chamber is considered to be universal among pseudoscorpions, but with our marine species it uses it far more each day than other species for the act of protection from the environment. An amazing animal.

Is this a record? Is this the only photo on the web of this species? We have never come across others, they tend to be drawings only. Please let us know.

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