Archidoris pseudoargus

Archidoris pseudoargus Rapp, 1827

Archidoris pseudoargus feeding on Amphilectus fucorum @ Isle of Man by Bernard Picton

Taxonomic Note: The species originally described as Doris pseudoargus Rapp, 1827 has undergone multiple taxonomic revisions over time, particularly regarding its generic placement. Historically, the name Doris tuberculata was widely misapplied to this species due to its usage by various authors following Cuvier (1804). However, Doris pseudoargus by Rapp (1827) represents the first valid description of the species with its distinctive morphological characteristics. A significant taxonomic change occurred when Iredale & O’Donoghue (1923) assigned the species to the genus Archidoris, a decision later followed by authors such as Thompson (1966), Schmekel & Portmann (1982), and Picton & Morrow (1994). However, Valdés (2002) synonymized Archidoris with Doris, arguing that the morphological differences were insufficient to justify a separate genus. Recent molecular phylogenetic analyses conducted by Fernández-Vilert et al. (2024) have provided new insights into the systematics of the family Discodorididae. Their results indicate that Doris sensu Valdés (2002) is not monophyletic and that Archidoris should be reinstated as a valid genus. Phylogenetic results support the recognition of Archidoris pseudoargus as a species that does not belong to Doris but is more closely related to other northern hemisphere taxa traditionally placed within Archidoris and Austrodoris.

Synonyms

• Doris pseudoargus (Rapp, 1827)
• Archidoris tuberculata (Müller, 1778) sensu Cuvier, 1804
• Doris areolata Stuwitz, 1836 
• Doris brittanica Johnston, 1838 
• Doris flavipes Leuckart, 1828
• Doris leuckarti Delle Chiaje, 1841
• Doris leuckartii Delle Chiaje, 1841 
• Doris mera Alder & Hancock, 1844 
• Doris schembrii Vérany, 1846

Description
This is one of the largest doridaceans in European waters, as it can reach up to 12 cm long, but it is frequently found only 5-8 cm long. The body is oval and fairly flat. The color is very variable, predominantly yellowish or orange specimens with brown or reddish spots of different shades and sizes scattered throughout the notum. The mantle has many tightly placed rounded tubercles of different sizes. Larger tubercles may have other much smaller tubercles on their surface and spicules inside. In many specimens’ tubercles there are white granulations. The rhinophores have an alaminar, wide, whitish base and while the laminar portion is yellowish and has up to 30 very thin lamellae. The rhinophoric orifice is slightly elevated and tuberculate. The gill consists of 8-10 tripinnate gill leaves paler than the body color, the uppermost gill leaves’ finlets (pinnulae) may have brown or reddish-brown stains. The foot is wide and yellowish, like the underside of the mantle, which lacks all types of stains. The anterior part of the foot is furrowed and the mouth and has a pair of rounded expansions acting as oral palps.

Biology
This species of nudibranch is often found under rocks in the intertidal zones of the European Atlantic coasts. In the Mediterranean it is less common and lives in the infralittoral to a certain depth, also in commercial trawlers’ fishing grounds on the upper continental shelf. It has been cited feeding on sponges like Halichondria panicea, Hymeniacidon sanguinea, Myxilla incrustans, Suberites ficus and Tethya aurantia, among others (Urgorri & Besteiro, 1984; McDonald & Nybakken, 2009). The spawn consists in a spirally wound ribbon with yellow or orange eggs about 150 microns in diameter (Schmekel & Portmann, 1982). It is often infested by the copepod ectoparasite Doridicola agilis.

Etymology

• Archidoris. From ancient Greek “archaios”, old + Doris. In Greek mythology Doris was a sea nymph, one of the many children of Oceanus and Tethys, wife of Nereus and mother of the Nereids.
• Pseudoargus. From Latin “pseudo”, false + “argus”, from the Greek Αργος (Argos), derived from αργος (argos) meaning “glistening, shining”. In Greek myth this name belonged to both the man who built the Argo and a man with a hundred eyes. For some time it was mistaken with Doris argus Philippi, 1844 nowadays a synonym of Platydoris argo, a different species, so the specific name was changed to pseudoargus, “false argo”.

Distribution
This species has a very wide distribution as it has been quoted from northern Europe, in Norway, to the Mediterranean Sea. In the Iberian Peninsula it has been reported in almost all coastal areas and in the Balearic islands (Cervera et al. 2004). In the coasts of Catalonia there are reports of this species in Llançà, in different trawling grounds like those near Blanes and Lloret de Mar, in front of Pineda de Mar and Malgrat, also in front of Barcelona and south down to the coast of Garraf, Sitges and Vilanova i la Geltrú.

Videos

 

More pictures

Bibliography

1246567 Archidoris pseudoargus 1 eunomia-revista-en-cultura-de-la-legalidad 50 creator asc 1 482 https://opistobranquis.info/wp-content/plugins/zotpress/
Bibliography based on the works by Steve Long, 2006. Bibliography of Opisthobranchia 1554-2000 and Gary McDonald, 2009. Bibliographia Nudibranchia, with later updates from other resources.

Further reading

• AsturNatura
• Biodiversity Heritage Library
• BiologiaMarina.org
• DORIS
• El Litoral de Granada
• Encyclopedia of Marine Life of Britain and Ireland
• Estran 22 - Faune et flore de la zone de balancement des marées en Côtes d'Armor
• European Sea Slugs by Morddyn
• Flickr pictures
• Interim Register of Marine and Nonmarine Genera
• Medslugs (Atl.NE)
• NCBI GenBank
• OBIS - Search by Taxon
• Scottish Nudibranchs
• Sea Slug Forum
• The Conchological Society of Great Britain and Ireland
• World Register of Marine Species

Cite this article as: