Durham Slug - Arion flagellus


    60-100mm. Often greenish but can range from yellow to black. Usually larger than the similar A. subfuscus, it is also distinguished by its colourless mucous (orange in A. subfuscus) and the large tubercles on its back (only 6-9 rows between the dark bands behind the mantle). The crests of the tubercles are often pointed and may also be highlighted yellow. The sole is nearly always paler than the body and generally has a greenish tint. The foot fringe doesn't contrast with the body colour and the lineations don't extend very far across the sole.

    Identification difficulty
    ID guidance
    • large, often pointed tubercles
    • clear mucus
    • pale, sometimes green tinted sole
    Recording advice

    Unless identified by a recognised expert, a photo is required. If the photo doesn't show the key ID features then in the comments box describe the size and identifying characters you have observed.


    Disturbed habitats, wasteground, roadsides and gardens.

    UK Status

    Widespread but patchily distributed and probably under-recorded, most records coming from the western half of Britain.

    VC55 Status

    Uncommon in Leicestershire and Rutland.

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    Leicestershire & Rutland Map

    MAP KEY:

    Yellow squares = NBN records (all known data)
    Coloured circles = NatureSpot records: 2020+ | 2015-2019 | pre-2015

    UK Map