Fiona pinnata

Fiona pinnata (Eschscholtz, 1831)

Fiona Pinnata 40mm @ Cala Rajada, Mallorca 25-06-2020 by David Martinez & Joan Sans










































Fiona pinnata  (Eschscholtz, 1831)

 Classification according to Bouchet et al. (2017)
Taxonomic source: World Register of Marine Species (AphiaID: 139942).

  • Doris fasciculata Gmelin, 1791 
  • Eolidia longicauda Quoy & Gaimard, 1832
  • Eolidia natans d’Orbigny, 1837
  • Eolidia pinnata Eschscholtz, 1831 (original)
  • Fiona atlantica Bergh, 1857 
  • Fiona marina Eliot, 1910 
  • Hymenaeolis elegantissima Costa A., 1867 
  • Limax marinus Forsskål in Niebuhr, 1775 
  • Oithona nobilis Alder & Hancock, 1851

Animals of 50 mm in length have been reported, but the most common size is about 20 mm. Its color varies depending on its food from white to brown or violet blue. Oral tentacles and rhinophores are very similar and short, rhinophores are smooth. The ceratas are very numerous, without being apparently grouped and are directed sideways, each cerata has a somewhat scalloped membranous band on its inner face and lacks a cnidosac at its distal end. The margin of the foot is scalloped and lacks propodial tentacles. The anus leads to a dorsolateral anal papilla, located approximately in the center of the body. Alder & Hancock (1851) made a remarkable anatomical description of this species under the name of Oithona nobilis.

It is one of the few pelagic nudibranch species that lives on the high seas on floating objects. It feeds on cirriped crustaceans of the genus Lepas that grow on these floating objects (Wirtz, 1998, 1999). It has also been mentioned that it feeds on pelagic hydrozoans such as Velella velella (Wirtz, 1998) and Porpita porpita. If it finds adequate food, F. pinnata has a very fast growth rate, reaching a size of 20 mm in just 4-5 days.


  • Fiona. Latinised form of the Gaelic word fionn, meaning “white”, “fair”.
  • Pinnata. From Latin “pinnātus”, feathered, pinnate, winged.

It is a cosmopolitan species that has been reported in all the world’s oceans. The featured picture on this page corresponds to a finding by David Martínez and Joan Sans on 25/06/2020 of about 30 specimens, including adults (up to 40mm.), juveniles and egg spawns, who lived in a plastic fruit box drifting along the coast of Cala Rajada (Mallorca). In Catalonia it has been found in few locations, always associated with floating objects that reach the coast.

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

Similar species
Due to its morphology and way of life, it does not resemble any other nudibranch.


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

This chart displays the monthly observation probability for Fiona pinnata based on our own records.

More pictures


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Further reading

Cite this article as:

Ballesteros, M., Madrenas, E. & Pontes, M. (2023) "Fiona pinnata" in OPK-Opistobranquis. Published: 13/08/2014. Accessed: 14/04/2024. Available at (

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