Ercolania coerulea

Ercolania coerulea (Trinchese, 1892)

Ercolania caerulea @ Porto Cesareo (Lecce), Northern Ionian Sea by Fabio Vitale




































Ercolania coerulea  Trinchese, 1892

 Classification according to Bouchet et al. (2017)
Taxonomic source: World Register of Marine Species (AphiaID: 141560).

  • Ercolania costai Pruvot-Fol, 1951
  • Stiliger cricetus Er. Marcus & Ev. Marcus, 1970

The average size of this species is about 14 mm but, generally, the specimens found are smaller. The overall body color is whitish or yellowish and the digestive gland, seen by transparency, is olive-green. This gland extends under all of the dorsal surface and the inside of the cerata, giving the animal an olive appearance. An opaque white pigment appears in the apex of the rhinophores and the pericardium. There are often numerous opaque white spots on the dorsum of the cerata that at the apex form two diverging white lines, like letter “V”. The apex of the cerata is bright blue, detail that gives its name to this species. The rhinophores are elongated and smooth, greenish-white in the base and at its end. The back is covered with a large number of cerata on both sides of the animal that remain tight together; cerata shape differs from fusiform with a pointed apex, to inflated with a rounded apex, depending on the movement state of the animal. The anal papilla is elongated and it is positioned on the pericardium. The genital openings are located just behind the right rinophore. The tail is pointed.

Ercolania coerulea is usually found on the cladophoral algae Vallonia utricularis that, according to various authors, it feeds. on. Its small size, globe shaped cerata and color makes the animal almost unnoticeable on the algae. The spawn of this species is a flattened round cord with very small white eggs, about 60-70 microns in diameter. The depth distribution ranges from the intertidal zone to a depth of 20 meters.


  • Ercolania. Probably dedicated to Giovanni Batista Ercolani, Italian physicyst and founder of the veterinary sciences in his country.
  • Coerulea. From Latin “caeruleus”, of blue color.

This species of sacoglosan was originally cited in the Mediterranean (Gulf of Naples) and has been quoted all around the western Mediterranean and the Adriatic, in the Canary Islands, Madeira and Azores, in the western Atlantic (Florida and West Indies), off the coast of Tanzania (Indian Ocean), and there are quotes from Hong Kong and Japan that require confirmation. In the Iberian Peninsula is mentioned only in the east coast. In the Catalan coast it has been observed rarely in the Costa Brava.

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


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

This chart displays the monthly observation probability for Ercolania coerulea based on our own records.

More pictures


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    Ballesteros M, Madrenas E, Pontes M. 2016. Actualización del catálogo de los moluscos opistobranquios (Gastropoda: Heterobranchia) de las costas catalanas. Spira. 6:1–28.
    Ballesteros M, Madrenas E, Pontes M. 2023. OPK - Opistobranquis. Available from
    Bielecki S, Cavignaux G, Crouzet JM, et al. 2011. Des limaces de rêve.
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    Pontes M, Dacosta JM, Ollé i Callau A, et al. 2023. M@re Nostrum. Available from
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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:

Ballesteros, M., Madrenas, E. & Pontes, M. (2023) "Ercolania coerulea" in OPK-Opistobranquis. Published: 14/05/2012. Accessed: 04/03/2024. Available at (

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