A sea slug (Tritonia hombergii)

Distribution data supplied by the Ocean Biogeographic Information System (OBIS). To interrogate UK data visit the NBN Atlas.

Researched byJessica Heard Refereed byAdmin
AuthorityCuvier, 1803
Other common names- SynonymsTritonia hombergii , Tritonia hombergi

Summary

Description

Tritonia hombergii 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.

Recorded distribution in Britain and Ireland

Occurs all around the Britain and Ireland

Global distribution

Recorded from the coasts of the British Isles and the Channel coast of France, with scattered records in the North Sea and east into the Skagerrak. 

Habitat

Tritonia hombergii can be  found down to depths of 80 m and is always associated with the soft coral Alcyonium digitatum.

Depth range

0-80 m

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

Tritonia hombergii has annual life cycle and the juveniles were once thought to be a different species known as Tritonia alba.  Tritonia hombergii is one of the few opisthobranchs 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).

Listed by

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Further information sources

Search on:

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Bibliography

  1. Hayward, P., Nelson-Smith, T. & Shields, C. 1996. Collins pocket guide. Sea shore of Britain and northern Europe. London: HarperCollins.

  2. Picton, B. E. & Morrow, C.C., 1994. A Field Guide to the Nudibranchs of the British Isles. London: Immel Publishing Ltd.

  3. Thompson, T. E. & Brown, G. H., 1976. British Opisthobranch Molluscs. London: Academic Press. [Synopses of the British Fauna, no. 8.]

Citation

This review can be cited as:

Heard, J.R. 2008. Tritonia hombergii A sea slug. In Tyler-Walters H. and Hiscock K. (eds) Marine Life Information Network: Biology and Sensitivity Key Information Reviews, [on-line]. Plymouth: Marine Biological Association of the United Kingdom. Available from: http://www.marlin.ac.uk/species/detail/2114

Last Updated: 17/04/2008