Biodiversity & Conservation

A sea slug - Acteon tornatilis

Acteon tornatilis

Image Hilmar Hinz - Acteon tornatilis shell, approximately 1.5 cm. Image width ca 2.5 cm.
Image copyright information

  • #
  • #
Distribution map

Acteon tornatilis recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

Why do the maps differ?

Sightings Have you seen Acteon tornatilis?
If so please submit your record.

Acteon tornatilis is not listed under any importance categories.

Taxonomy icon Taxonomy Taxon English term
Phylum Mollusca Snails, slugs, mussels, cockles, clams & squid
Class Gastropoda Snails, slugs & sea butterflies
Authority (Linnaeus, 1758)
Recent synonyms None
Map icon Recorded Distribution in Britain and Ireland Acteon tornatilis has been recorded from scattered locations around the UK and Ireland. Records are rare from the east coast of England.
Habitat information icon Habitat information Acteon tornatilis is found especially in sheltered sandy bays or in deep water from low water to 250 m depth. As well as inhabiting sandy sediments, Acteon tornatilis is also found in sandy mud and gravel. Acteon tornatilis has occasionally been found in the holdfasts of Laminaria hyperborea from Beadnell, north-east England.
Text page icon Description Acteon tornatilis is a primitive sea slug within a thick, opaque, pink, external shell of up to 2-3 cm that is marked by 1-3 white bands on the body whorl and 1 white band on the remainder. Either side of each band is a narrow margin of dark pink. It is able to withdraw the whole of its body into its shell which is then sealed by an amber-coloured operculum. The shell aperture accounts for two-thirds of the shell length. Inside the lip of the shell is a distinctive tooth. The head of Acteon tornatilis has four large lobes and a cephalic disc that is used in burrowing through clean, fine sand together with a small foot that has blunt, propodial tentacles. Inside of the shell are folded mantle flaps.
Identifying features
  • Thick, opaque, shell coloured pink.
  • Body whorl is marked with 1-3 white bands.
  • Remaining whorls marked with 1 white band.
  • Each side of the white bands has a narrow margin of dark pink.
  • Distinctive tooth on inside of lip.
  • Head has four large, flattened lobes.
Additional information icon Additional information

Acteon tornatilis is a carnivore, feeding on tubiculous, infaunal polychaetes, including Owenia fusiformis and Lanice conchilega.

Acteon tornatilis has previously been known as Tornatella fasciata (pre-1950). Four species of the Acteon genus are found in Europe.

This review can be cited as follows:

Saskiya Richards 2008. Acteon tornatilis. A sea slug. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 25/05/2013]. Available from: <http://www.marlin.ac.uk/speciesinformation.php?speciesID=2352>