Description: A 'keeled' roundback slug but the keel is inconspicuous except in very young specimens. Larger and much rarer than the other two keeled roundbacks Arion circumscriptus and A. silvaticus. Has a paler, brown back with moderately thin lateral bands, and a distinct yellowish flush along the sides, which sometimes spreads on to the sole. 35-42 mm.

World Distribution: Mainly middle and northern latitudes in Europe. Distribution type: European Temperate (73).

Irish Distribution: Very local and uncommon and mainly in eastern and southern counties.

Ecology:

• A naturalised introduction in Ireland
• Mainly in disturbed or waste places
• Sometimes in old woodland but not gardens

Key Identification Features:

• The largest of the three keeled roundbacks and much paler overall with thin lateral abands and pale sides and sole
• Sides marked by a distinct yellowish flush
• Keel dificult to see in adult specimens
• Mucus thick, sticky, yellowish
• Contracts to a bell shape
• Sole pale yellowish from the pigment on the sides reaching the underside

Red list status:

• Not applicable.

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

iNaturalist: Arion fasciatus at iNaturalist World Species Observations database.

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

Thumbnails for genus Arion