MolluscIreland - land and freshwater
  • Tandonia sowerbyi (A. Férussac 1823) Sowerby
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Tandonia sowerbyi
© Dr Roy Anderson
Tandonia sowerbyi
© Dr Roy Anderson
Tandonia sowerbyi
© 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 medium to large keeled slug, pale brownish-grey to dark grey speckled with black. Respiratory pore rimmed pale orange. Keel yellow or orange. Sole pale, mucus yellowish and very sticky. Forms a half-moon shape when disturbed. Widespread.

Key characteristics

  • A medium to large keeled slug with yellowish or orange mucus
  • Usually mid to dark grey in colour speckled with black and with a contrasting yellow or orange keel
  • Breathing pore rimmed orange
  • Contracts into a compact, half-moon profile when irritated
  • Mucus yellow to orange and very sticky
  • Mantle granular with a deep horseshoe-shaped groove


60-75 mm.

World Distribution

Mostly found in the western Mediterranean and along coasts north to the British Isles. Distribution type: Mediterranean-Atlantic (91).

GBIF distribution map [open in new tab]

Irish Distribution

Widespread in synanthropic situations but commonest in southern counties.


  • Generally restricted to disturbed places in woods and gardens
  • Established occasionally in semi-natural woodland

Red List status

  • Least concern (lc).

Wikipedia link

Wikipedia page for Tandonia sowerbyi

 Anderson, R., (2016). Tandonia sowerbyi (A. Férussac 1823). [In] MolluscIreland. Accessed on 2024-03-02.