This is a dark purplish-red species, capable of rapid movement, somewhat reminiscent of a large Trichoniscus pusillus. However, it differs in the eye being composed of a single prominent ommatidium and both eye and body pigments fade in alcohol to a pale straw colour (T. pusillus has three ommatidia and body pigments are retained).
Distribution and Habitat
This species is virtually confined to Ireland, where it is locally common across much of south-east. It was unknown in Britain until 1994 when a site was discovered in south Wales. In 2010 a population was discovered in Scotland (Sivell & Gregory, 2012).
It is characteristically associated with river and stream valleys, often inhabiting rough vegetation beside watercourses, where it occurs among leaf litter, under stones and dead wood.