Armadillidium nasatum

Distinguished from Armadillidium vulgare by the prominent rectangular "nose" protrusion at the head apex and the rounded, incurved tail (telson) tip; A. vulgare has a smaller, flat tail. Unlike A. depressum, does not form a complete ball when enrolled. Dark grey coloration similar to A. vulgare; pale longitudinal stripes occasionally present but variable and non-diagnostic.

Occupies drier microhabitats than most woodlice. Synanthropic; frequently found in non-inhabited areas including railway lines and industrial waste ground. Shelters under stones and wood.

Native to Western Europe, particularly Britain (patches in southern England, sporadic in Ireland). Introduced to North America and other parts of Europe.

Exhibits aggregation behavior and shelter-seeking responses when exposed to fluorescent and ultraviolet light; demonstrates negative phototaxis/photophobia in laboratory conditions.

Synanthropic species associated with human-modified environments; introduced beyond native range.

• Armadillidium vulgareSimilar dark grey coloration and general appearance, but distinguished by lack of "nose" protrusion and flat (not rounded/incurved) tail tip
• Armadillidium depressumAlso does not form complete ball when enrolled, but lacks the distinctive head "nose" and has different tail morphology

• isopod
• woodlouse
• pill bug
• introduced species
• synanthropic
• Europe
• North America
• terrestrial crustacean

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• Bohart Museum Open House on 'Many Legged Wonders': How Many Legs Does an Isopod Have? | Bug Squad
• ID Challenge #18 | Beetles In The Bush
• Eumastacidae | Beetles In The Bush
• Aggregation and sheltering behavior of Armadillidium vulgare and Armadillidium nasatum (Isopoda: Armadillidiidae) exposed to fluorescent and ultraviolet light