Blue spot slug (Polycera elegans)

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



A distinctive colourful sea slug. The smooth body is orange in colour with brilliant blue blotches that sometimes contain crimson flecks. It has 5 - 7 robust and feathery trilobed gills with iridescent blue-green lines along their ribs. The head may bear up to 22 finger-like projections. It can grow up to 4 cm in length although a maximum size of 4.8 cm has been recorded.

Recorded distribution in Britain and Ireland

Kilkieran Bay, Co. Galway; Sheep Haven, Co. Donegal; Skomer Island, Pembrokeshire; Lundy, south Cornwall.

Global distribution



Found on rocky coasts feeding on the erect bryozoan Bugulina turbinata and probably other species of Bugula.

Depth range


Identifying features

  • Orange colouration with large iridescent blue spots.
  • Rhinophores and gills without sheaths or accessory processes.
  • Frontal veil produced anteriorly into small digitiform papillae.
  • Up to seven large, trilobed gills.

Additional information

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Listed by

- none -


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

  2. Hayward, P.J. & Ryland, J.S. (ed.) 1995b. Handbook of the marine fauna of North-West Europe. Oxford: Oxford University Press.

  3. Howson, C.M. & Picton, B.E., 1997. The species directory of the marine fauna and flora of the British Isles and surrounding seas. Belfast: Ulster Museum. [Ulster Museum publication, no. 276.]

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

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


  1. NBN (National Biodiversity Network) Atlas. Available from:

  2. OBIS (Ocean Biodiversity Information System),  2024. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. Accessed: 2024-04-20


This review can be cited as:

Wilson, E. 1999. Polycera elegans Blue spot slug. In Tyler-Walters H. and Hiscock K. Marine Life Information Network: Biology and Sensitivity Key Information Reviews, [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 20-04-2024]. Available from:

Last Updated: 14/09/1999