Trichoniscus provisorius Racovitza, 1908
- Trichoniscus pusillus form provisorius Racovitza, 1908
- Trichoniscus pusillus ssp. provisorius Racovitza, 1908
GB IUCN status: Least Concern
The pygmy woodlice of family Trichoniscidae (and Styloniscidae) are readily distinguished from other woodlice by the shape of the antennal fagellum which comprises a tapered cone (of indistinct segments) bearing a terminal bristle.
Trichoniscus provisorius 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 and BMIG Newsletter 18, pg.2).
Trichoniscus provisorius appears to be very common throughout Britain and Ireland but unfortunately most records do not differentiate 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 (both species my occur in close proximity). It is readily found under stones, dead wood, etc.
This summary is based on the detailed account in Gregory (2009).