A sea slug (Goniodoris nodosa)

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



Goniodoris nodosa has an elongate oval body up to 3 cm in length. It is translucent white with specks of white or yellow pigmentation on the upper surface, which may also have a slightly pink hue. The short mantle has a characteristic wavy edge fringed with a yellow colouration. It has a low longitudinal ridge, often yellow and flanked with small conical tubercles. This ridge extends through to the tip of the foot, which may also have yellow pigments. The rhinophores of this species are covered with scales and faintly yellow with opaque, white spots. The smooth oral tentacles are flattened, protrude laterally and are visible from above. There are up to 13 fat, fleshy gills that encircle the anal papilla. Interestingly, there are transparent patches of skin mainly around the base of the rhinophores and behind the gills that give the appearance of a 'false pore' (Rudman, 2001; Thompson, 1988; Moen & Svensen, 2004).

Recorded distribution in Britain and Ireland

Found throughout the British Isles and Ireland.

Global distribution



Adults may often be food feeding on ascidians, whereas juveniles may be found on bryozoans.

Depth range


Identifying features

  • An elongate oval body up to 3 cm in length.
  • The body is translucent white with a short, wavy, yellow edged mantle.
  • An opaque longitudinal ridge runs down the back to the tip of the foot.
  • The lamellate rhinophores are faintly yellow with opaque, white spots.
  • The smooth oral tentacles are flattened and protrude latterally.
  • Up to 13 fat, fleshy gills around the anal papilla.

Additional information

The breeding season in Goniodoris nodosa occurs mainly between January-June, but has been noted in September and December (MBA, 1957). Large numbers of spawning adults have been observed in Plymouth Sound from February-May with a marked abundance of smaller individuals from June-August, suggesting an annual spawning event by this species to the shores (MBA, 1957). Goniodoris nodosa is very similar to Goniodoris castanea. However, Goniodoris castanea is a much rarer species, with a conspicuous reddish-brown colour and covered in small white flecks.

The juveniles of Goniodoris nodosa feed on encrusting bryozoans, mainly Alcyonidium diaphanum, Callopora dumerilii and Flustrellidra hispida. As adults, Goniodoris nodosa transfer to encrusting ascidans as adults, mainly Botryllus schlosseri, Diplosoma listerianum and Dendrodoa grossularia. However, Bruce (1963) noted that in sheltered localities they could occasionally be found on Fucus serratus and Chondrus crispus.


Listed by

- none -


  1. Allen, J.A. 1962. The fauna of the Clyde Sea area. Mollusca. Millport: Scottish Marine Biological Association.

  2. Bruce, J.R., Colman, J.S. & Jones, N.S., 1963. Marine fauna of the Isle of Man. Liverpool: Liverpool University Press.

  3. Costello, M.J., Bouchet, P., Boxshall, G., Emblow, C. & Vanden Berghe, E., 2004. European Register of Marine Species [On-line]. http://www.marbef.org/data/erms.php,

  4. Foster-Smith, J. (ed.), 2000. The marine fauna and flora of the Cullercoats District. Marine species records for the North East Coast of England. Sunderland: Penshaw Press, for the Dove Marine Laboratory, University of Newcastle upon Tyne.

  5. Gibson, R., Hextall, B. & Rogers, A., 2001. Photographic guide to the sea and seashore life of Britain and north-west Europe. Oxford: Oxford University Press.

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

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

  8. 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.]

  9. MarLIN (Marine Life Information Network), 2005. SEArchable BEnthic Data (SEABED) Map [on-line]. Data Access Sub-programme, Marine Life Information Network for Britian and Ireland http://www.marlin.ac.uk,

  10. MBA (Marine Biological Association), 1957. Plymouth Marine Fauna. Plymouth: Marine Biological Association of the United Kingdom.

  11. Moen, F.E. & Svensen, E., 2004. Marine Fish & Invertebrates of Northern Europe. Southend-on-Sea: Aqua Press.

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

  13. Picton, B.E. & Costello, M.J., 1998. BioMar biotope viewer: a guide to marine habitats, fauna and flora of Britain and Ireland. [CD-ROM] Environmental Sciences Unit, Trinity College, Dublin.

  14. Rudman, W.B., 2001. Goniodoris nodosa [on-line]. http://www.seaslugforum.net/showall.cfm?base=goninodo, 2007-02-27

  15. Seaward, D.R., 1990. Distribution of marine molluscs of north west Europe. Peterborough: Nature Conservancy Council.


  1. Centre for Environmental Data and Recording, 2018. Ulster Museum Marine Surveys of Northern Ireland Coastal Waters. Occurrence dataset https://www.nmni.com/CEDaR/CEDaR-Centre-for-Environmental-Data-and-Recording.aspx accessed via NBNAtlas.org on 2018-09-25.

  2. Conchological Society of Great Britain & Ireland, 2018. Mollusc (marine) data for Great Britain and Ireland - restricted access. Occurrence dataset: https://doi.org/10.15468/4bsawx accessed via GBIF.org on 2018-09-25.

  3. Conchological Society of Great Britain & Ireland, 2018. Mollusc (marine) records for Great Britain and Ireland. Occurrence dataset: https://doi.org/10.15468/aurwcz accessed via GBIF.org on 2018-09-25.

  4. Environmental Records Information Centre North East, 2018. ERIC NE Combined dataset to 2017. Occurrence dataset: http://www.ericnortheast.org.ukl accessed via NBNAtlas.org on 2018-09-38

  5. Fenwick, 2018. Aphotomarine. Occurrence dataset http://www.aphotomarine.com/index.html Accessed via NBNAtlas.org on 2018-10-01

  6. Kent Wildlife Trust, 2018. Kent Wildlife Trust Shoresearch Intertidal Survey 2004 onwards. Occurrence dataset: https://www.kentwildlifetrust.org.uk/ accessed via NBNAtlas.org on 2018-10-01.

  7. Manx Biological Recording Partnership, 2018. Isle of Man historical wildlife records 1990 to 1994. Occurrence dataset:https://doi.org/10.15468/aru16v accessed via GBIF.org on 2018-10-01.

  8. Manx Biological Recording Partnership, 2018.  Isle of Man Wildlife Records. Occurence datasets https://registry.nbnatlas.org/public/show/dp115 Accessed on www.NBNAtlas.org on 2018-09-05.

  9. National Trust, 2017. National Trust Species Records. Occurrence dataset: https://doi.org/10.15468/opc6g1 accessed via GBIF.org on 2018-10-01.

  10. NBN (National Biodiversity Network) Atlas. Available from: https://www.nbnatlas.org.

  11. OBIS (Ocean Biodiversity Information System),  2024. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. www.iobis.org. Accessed: 2024-05-20

  12. South East Wales Biodiversity Records Centre, 2018. SEWBReC Molluscs (South East Wales). Occurrence dataset: https://doi.org/10.15468/jos5ga accessed via GBIF.org on 2018-10-02.


This review can be cited as:

Rowley, S.J. 2007. Goniodoris nodosa A sea 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 20-05-2024]. Available from: https://www.marlin.ac.uk/species/detail/5

Last Updated: 04/09/2007