MolluscIreland - land and freshwater
  • Arion (Carinarion) fasciatus (Nilsson 1823) Banded slug
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Arion (Carinarion) fasciatus
© Dr Roy Anderson
Arion (Carinarion) fasciatus
© Dr Roy Anderson
Arion (Carinarion) fasciatus
© Dr Roy Anderson

Map hosted by the National Biodiversity Data Centre, Waterford
To view the species profile on Biodiversity Maps and access the live map, please click on the map.


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.

Key characteristics

  • 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


35-42 mm.

World Distribution

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

GBIF distribution map [open in new tab]

Irish Distribution

Very local and uncommon and mainly in eastern and southern counties.


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

Red List status

  • Not applicable.

Wikipedia link

Wikipedia page for Arion fasciatus

 Anderson, R., (2016). Arion (Carinarion) fasciatus (Nilsson 1823). [In] MolluscIreland. Accessed on 2024-03-03.