Yellow false doris (Adalaria proxima)

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



Adalaria proxima is a substantial sea slug with a broad yellow body covered in fleshy projections (tubercles). Near the rear end is a circle of feathery gills and near the front end are antenna-like rhinophores that have a ribbed or stacked-plate like appearance (lamellate).

Recorded distribution in Britain and Ireland

A northern species in Britain, with it southern limit in north Wales.

Global distribution



Adalaria proxima feeds on sea mats (bryozoans) that encrust seaweed and is found in the intertidal and shallow sublittoral, mostly on Electra pilosa but also on species of Membranipora, Alcyonidium and Flustrellidra.

Depth range


Identifying features

  • An oval shaped sea slug up to 17 mm long.
  • Most individuals yellow all over but may be white in northern Britain.
  • Body is covered in small club shaped tubercles, with pointed tips.
  • Twelve gills surrounding anal papilla.
  • Rhinophores lamellate.

Additional information

Adalaria proxima may be confused with Onchidoris muricata but Adalaria proxima has a deeper colour and the rhinophores (tentacles at the front end longer than the tubercles) are more blunt at the tip.

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. 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.]

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

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


  1. Bristol Regional Environmental Records Centre, 2017. BRERC species records recorded over 15 years ago. Occurrence dataset: accessed via on 2018-09-25.

  2. Centre for Environmental Data and Recording, 2018. Ulster Museum Marine Surveys of Northern Ireland Coastal Waters. Occurrence dataset accessed via on 2018-09-25.

  3. Conchological Society of Great Britain & Ireland, 2018. Mollusc (marine) data for Great Britain and Ireland - restricted access. Occurrence dataset: accessed via on 2018-09-25.

  4. Conchological Society of Great Britain & Ireland, 2018. Mollusc (marine) records for Great Britain and Ireland. Occurrence dataset: accessed via on 2018-09-25.

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

  6. OBIS (Ocean Biodiversity Information System),  2024. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. Accessed: 2024-07-21

  7. South East Wales Biodiversity Records Centre, 2018. Dr Mary Gillham Archive Project. Occurance dataset: accessed via on 2018-10-02


This review can be cited as:

Neal, K.J. 2007. Adalaria proxima Yellow false doris. 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 21-07-2024]. Available from:

Last Updated: 04/06/2007