Biodiversity & Conservation

Sea lemon - Archidoris pseudoargus

Archidoris pseudoargus

Image Jack Sewell - The sea lemon Archidoris pseudoargus. Image width ca 10 cm.
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Distribution map

Archidoris pseudoargus recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

Why do the maps differ?

Sightings Have you seen Archidoris pseudoargus?
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Archidoris pseudoargus 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 (Rapp, 1827)
Recent synonyms None
Map icon Recorded Distribution in Britain and Ireland Found all around the British Isles.
Habitat information icon Habitat information Found on the lower shore underneath large boulders and offshore into the sublittoral to about 300 m.
Text page icon Description A large sea slug up to 12 cm long. The top side of the slug is covered in small wart like bumps (tubercles). It has a ring of eight or nine upright feathery gills close to the posterior end, which are quickly retracted when a disturbance is sensed. The colouration of the sea slug is blotchy and variable and can be yellow, green, brown or pink. There is another variety Archidoris psuedoargus var. flammea which is bright red all over.
Identifying features
  • Oval body up to 12 cm long.
  • Mottled in colour, usually yellow but can be green, brown or pink.
  • Top side covered in small wart like bumps.
  • Ring of 8-9 feathery upright (tripinnate) gills near posterior end.
Additional information icon Additional information The sea slug Geitodoris planata can be distinguished from Archidoris psuedoargus as it has star-shaped spots on its back (dorsum) and brown specks on the underside of the mantle.
The sea lemon feeds mainly on sponges, especially the breadcrumb sponge (Halichondria (Halichondria) panicea). Once used as fish bait in Shetland (Thompson & Brown, 1976).

This review can be cited as follows:

Olwen Ager 2008. Archidoris pseudoargus. Sea lemon. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 25/05/2013]. Available from: <http://www.marlin.ac.uk/speciesinformation.php?speciesID=2585>