Trichoniscus pusillus ssp. provisorius Racovitza, 1908
This species is morphologically identical to T. pusillus sensu stricto, but is relatively smaller (gravid females rarely exceed 3.5 mm in length). It is a normal sexually reproducing species, with populations comprising approximately 50/50 male and females.
Males are readily recognised by microscopic examination of the first exopod ~ see image.
Distribution and Habitat
This is probably a very common throughout Britain and Ireland but unfortunately most records are not differentiated between the two species (simply given as T. pusillus agg.). Verified records (based on male specimens) indicate a wide distribution throughout Britain and Ireland, but it seems more common in areas where calcareous strata occur.
It favours sunnier and/or drier situations than Trichoniscus pusillus s.str., including semi-natural limestone grassland, free-draining woodland and domestic gardens, where it can be found under stones, dead wood, etc.