Eubranchus prietoi

Eubranchus prietoi Llera & Ortea, 1981

Eubranchus prietoi by José Carlos García Gómez










































Eubranchus prietoi  Llera & Ortea, 1981

 Classification according to Bouchet et al. (2017)
Taxonomic source: World Register of Marine Species (AphiaID: 139769).

Taxonomic note: The phylogenetic analyses performed by Cella et al. (2016) revealed that the traditional Tergipedidae family is polyphyletic and belongs to a larger monophyletic clade including members of the traditional families Eubranchidae, Fionidae and Calmidae; this was an unexpected result, since the validity of these taxa and their distinctness from the Tergipedidae was never questioned before. They proposed to join the families Tergipedidae, Eubranchidae, Calmidae and Fionidae under the name of Fionidae. This decision has been reinterpreted and completed in the paper by Korshunova et al. (2017) because it obviated evident morphological and molecular aspects.

Size up to 7 mm in length. Elongated and narrow body, coloured translucent white with dark brown and white spots and punctuations all over the body, including head, oral palps, rhinophores and cerata. Oral palps short, rhinophores long. Four or five groups of cerata on both sides of the back, the two anteriormost with two cerata and the rest with only one. Cerata are also semitransparent, quite long, narrow at the base and with tuberculate protrusions. The digestive gland, dark brown in color, can be seen by transparency on the back forming a zigzagging Y-shaped cord, from just behind the rhinophores and along the body; inside the cerata it is creamy white.

It lives and feeds on hydrozoans like Plumularia setacea. Egg strings are laid on top of the hydrozoan itself, are kidney-shaped and contain very few white eggs. It is a very cryptic species on the hydrariums where it lives.


  • Eubranchus, from Greek, means “true gills”.
  • Prietoi, dedicated to the Counselor of Trade, Tourism and Fisheries of the Regional Council of Asturias (Spain), Mr. Alfredo Prieto Valiente, in recognition of his efforts for the creation of CRINAS (Center for Aquatic Research of Asturias).

It has been reported from the Atlantic coasts of France, where it is very common in the Arcachon Bay, to the African coasts of Senegal and Ghana. Also observed in the western Mediterranean. In Catalonia it is a very rare species that has only been found in Tamariu and Sant Feliu de Guíxols.

Known georeferenced records of the species: Eubranchus prietoi
: GROC 2010-2011
: Enric Madrenas
: João Pedro Silva
: Bernard Picton
: Manuel Ballesteros.
: M@re Nostrum
: Altres fonts
: Marine Regions

Similar species
Eubranchus exiguus does not have a visible digestive gland in the form of a dark cord along the body, while in Tergipes tergipes, which does have it, the cerata are smooth.


    Western Mediterranean: ★☆☆☆☆
    Eastern Mediterranean: ☆☆☆☆☆
    Atlantic Ocean: ★★☆☆☆

This chart displays the monthly observation probability for Eubranchus prietoi based on our own records.

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    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

Cite this article as:

José Carlos García Gómez (2023) "Eubranchus prietoi" in OPK-Opistobranquis. Published: 29/12/2015. Accessed: 28/02/2024. Available at (

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