Armadillidium pictum Brandt, 1833
- GB IUCN status: Least Concern
- GB rarity status: Nationally Scarce
Our seven Armadillidium species and Eluma caelata (Family Armadillidiidae) are readily recognised in the field by their truncated 'square' uropods that end flush with the body and their ability to roll into a protective sphere (similar truncated uropods are also seen in the non-native Armadillidae species).
Armadillidium pictum is an attractively mottled pill-woodlouse (to 9 mm in body length). It shares its distinctive mottling and the dark patch on the 7th epimera with A. pulchellum (a smaller species). The shape of the male first pleopods in diagnostic, but females are more tricky. The common A. vulgare is never as attractively mottled, and lacks the dark patch on the 7th epimera.
A guide to identification of these three species is given by Gregory & Richards (2008).
This is a very rare pill woodlouse, known from cluster of sites in the English Lake District, the Pennines and the Welsh/English border counties. It is probably under-recorded. It has not been recorded from Ireland.
It is exclusively associated with semi-natural habitats, typically in hilly areas, including ancient deciduous woodland, rough and/or shady grassland and grikes in limestone pavement.
Although usually found under moss carpets and stones, amongst scree or within red-rotted timber, it can be beaten from shrubs and may occur under loose bark and within rot holes several metres high on mature trees. Some additional comments on its habitat associations is provided by Alexander (2010).
This summary is based on the detailed account in Gregory (2009).
Gregory, S. (2009) Woodlice and Waterlice (Isopoda: Oniscidea & Asellota) in Britain and Ireland. Field Studies Council/Centre for Ecology & Hydrology.
Gregory, S. & Richards, P. (2008) Comparison of three often mis-identified species of pill-woodlouse Armadillidium (Isopoda: Oniscidea). Bulletin of the British Myriapod & Isopod Group, 23: 9-12.