Biodiversity & Conservation

A sea slug - Tritonia hombergi

Tritonia hombergi

Image Sue Scott - Tritonia hombergi with eggs. Image width ca 10 cm.
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Distribution map

Tritonia hombergi recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

Why do the maps differ?

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Tritonia hombergi 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 Cuvier, 1803
Recent synonyms Tritonia hombergii
Map icon Recorded Distribution in Britain and Ireland Occurs all around the Britain and Ireland.
Habitat information icon Habitat information Tritonia hombergi can be found down to depths of 80 m and is always associated with the soft coral Alcyonium digitatum.
Text page icon Description Tritonia hombergi is the largest British nudibranch growing up to 20 cm in length. The body varies in colour from white to a dark purple brown and is lighter ventrally (colour darkens with age). The rhinophores are branched at the tip with basal sheaths. The mantle is covered with numerous soft tubercles, which release an irritant compound. On the sides of the upper surface there are noticeable gills, of varying size. The larger gills orientate towards the centre of the body while smaller gills flex out to the side. The total number of individual gills increases significantly with age. The front section of the head (the oral veil) is divided into two lobes and, characteristically for members of the genus Tritonia, each lobe is divided into numerous finger-like projections.
Identifying features
  • Body colour white to dark purple
  • Rhinophores branched at the tips and have basal sheaths.
  • Surface covered in numerous tubercles
  • Gills of vary size, large gills point towards centre of body, small gills point outwards.
  • Oral veil split into two lobes, each richly frilled.
Additional information icon Additional information Tritonia hombergi has annual life cycle and the juveniles were once thought to be a different species known as Tritonia alba.

Tritonia hombergi is one of the few opisthobranch thought to be harmful to man as its secretion has been reported to cause the skin to blister. However there have been no recent recorded evidence of this (Thompson & Brown, 1976).

This review can be cited as follows:

Jessica Heard 2008. Tritonia hombergi. 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 20/06/2013]. Available from: <http://www.marlin.ac.uk/speciesinformation.php?speciesID=4510>