Facelina fusca from Spain

June 5, 2008
From: Miquel Pontes

Concerning message #19253:

Hi Bill,

Here is a nice picture of a Facelina fusca where it shows all the traits theoretically assigned to this species (unlike other pictures on this thread). However, by finding this small and cryptic nudibranch, many questions arose.

We have read this species has been described in Spain only once (Ros, 1975 as Facelina cf. fusca, because the only available animal was in very bad shape for further determination). So maybe this is the second citation of a Facelina fusca in Mediterranean coast of Spain.

We have also read that this animal lives on coralligenous habitat (in our coast this habitat usually begins at -20m) feeding on Eudendrium sp. hydroids, but we found this one in the Posidonia oceanica meadows, on Posidonia leaves at 4 metres of water.

At the present time (May-June) newly grown Posidonia oceanica leaves are covered with epibiotic organisms, some of which we suppose could be this animal's food; this way it may replenish its cerata with hydroid stinging cells. We didn't see any Eudendrium sp. in the neighborhood, but we saw many Sertularia sp. (and other) hydroids instead.

I have noticed that some other pictures on this forum thread about Facelina fusca don't show the red line running along the dorsum, and some even show white cerata tips, while in the "classical" species' description they are black. This leads me to think we are talking about different species but, of course, there could be big local differences among specimens. A lot of work has to be done on this group.

NOTE: For taking this picture we separated the animal from the Posidonia leaves, and photographed it over a stone for clarity. After the picture, it was returned unharmed to the original habitat.

Locality: Platja de Sant Antoni, Badia de Portlligat, Cadaqués, Girona, 4 metres, Spain, Mediterranean Sea, 31 may 2008, Posidonia oceanica meadows. Length: 15 mm. Photographer: Miquel Pontes.

Miquel Pontes


Pontes, M., 2008 (Jun 5) Facelina fusca from Spain. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/21615

Dear Miquel,

It's nice to get a 'typical' example of Facelina fusca. Certainly the three records already on the Forum lack certain details, and as you say, one has white-tipped cerata. I will replace the photo on the Fact Sheet with yours. I guess the challenge now is for local enthusiasts to try and find more specimens and see just how much colour variation occurs in this species. Concerning other records from Spain, the only reference cited by Cervera et al. (2006) in their checklist is the one you mention (Ros, 1975) so clearly it has rarely been found there.

  • Cervera, J. L., Calado, G., Gavaia, C., Malaquias, M. A. E., Templado, J., Ballesteros, M., García-Gómez, J. C., & Megina, C. (2006) An annotated and updated checklist of the opisthobranchs (Mollusca: Gastropoda) from Spain and Portugal (including islands and archipelagos). Boletín Instituto Espanol de Oceanografía  20: 1-122.
  • Ros, J. 1975. Opistobranquios (Gastropoda: Euthyneura) del litoral ibérico. Investigación Pesquera, 39 (2): 269-372.

Best wishes,
Bill Rudman

Rudman, W.B., 2008 (Jun 5). Comment on Facelina fusca from Spain by Miquel Pontes. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/21615


Facelina fusca

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