Five subspecies Armadillidium nasatum, the nosy pill woodlouse, is a large, Western European-based species of woodlouse that has been introduced to North America, along with Armadillidium vulgare also found in other parts of Europe.

[2][5] Like Armadillidium depressum, it does not form a complete ball when enrolled.

[2] Though similar in outwards appearance to Armadillidium vulgare in dark grey color, the main distinguishing feature is a rectangular-like protrusion ("nose") towards the apex of the head.

[5] Pale longitudinal stripes spanning from head to rear are seen on some individuals, though this is variable and is not a diagnostic feature.

[6] Armadillidium nasatum occurs in patches in southern England, with concentrated areas in its range and sporadic occurrences in Ireland.