ARACHNIDA > OPILIONES > Phalangiidae > Oligolophinae

Oligolophus tridens is a rather dull, small, plain brown, relatively short-legged species with a body length of around 4-5mm.

The saddle can be somewhat variable in both shape and colour, although normally it is more defined and darker in the males and a bit blotchy in the females often appearing as though it's made up of a series of block-shaped spots. It is typically broad across the cephalothorax, before tapering off into a parallel band that runs down the abdomen where it ends abruptly in a pair of semi-circular patches. In some individuals the band may expand across the abdomen and in others it may blend into the background and difficult to see.

The ocularium is pale with two rows of tubercles.

They have an inconspicuous trident, which is difficult to see from above as the three body-coloured pointed tubercles are normally upward pointing. They are quite long, usually of equal length in males, or with the middle one a tad longer and forward pointing in females. You need a good photo from the right angle to capture them. The trident though is an important identification feature particularly when trying to distinguish the species from the very similar, although far less common, Oligolophus hanseni, which has five or more tubercles.

Oligolophus tridens is a ground and field-level nocturnal foraging species that during the day can be found in leaf-litter or under stones and logs, but also on low level vegetation and bushes. It occurs in a variety of habitats, particularly woodland, but also wetlands and gardens.

It's a relatively common and widespread species except that, for whatever reason, it doesn't appear to have ever been officially recorded from East Dorset, which may well account for the fact that I've never seen one locally. In fact, my only encounter so far was from much further west in South Devon.  

Adults are normally active from August to late November / early December, but with a distinct peak in  September.