Description: A medium-sized, dusky brown to orange roundback slug distinguished from other, similar species and their young by the very flat tuberculation on the back and by its inability to assume a bell shape when fully contracted. Common in woods and on wild ground but not in gardens. 50-70 mm.

World Distribution: Throughout Europe but commonest in the west. Distribution type: European Wide-temperate (63).

Irish Distribution: The second most common Irish slug after Deroceras reticulatum.

Ecology:

• Ubiquitous and abundant in all categories of land, except gardens, to the summits of high mountains including Slieve Donard, Co. Down (850m)
• Commonest in woodland where it hides under stones and dead wood

Key Identification Features:

• A medium-sized roundback slug of a predominantly brown colour, ranging from black-brown through olive-brown to orange, occasionally a bright reddish-orange
• Lateral bands nearly always present and of a slightly to moderately darker shade than the rest of the upper surface
• Foot fringe pale with thin lineolations (less well formed than the large roundback species)
• Sole uniformly pale, slightly translucent
• Tentacles pale
• Exhibits no rocking response and is unable to contract into a bell shape when stimulated

Red list status:

• Least concern (lc).

Distribution Map from NBN: Arion subfuscus at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Arion subfuscus at iNaturalist World Species Observations database.

GBIF data for Arion subfuscus | Classification: Gastropoda, Stylommatophora, Arionidae, Arion

Thumbnails for genus Arion