Calma gobioophaga

Calma gobioophaga Calado & Urgorri, 2002

Calma gobioophaga by Enric Madrenas










































Calma gobioophaga  Calado & Urgorri, 2002

 Classification according to Bouchet et al. (2017)
Taxonomic source: World Register of Marine Species (AphiaID: 181241).

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.

Calma gobioophaga has recently been described based on specimens captured off the coast of Portugal (Calado & Urgorri, 2002). So far, until its description, the only other known species of the genus Calma was C. glaucoides a strictly European species, known since 1854 and described by Alder & Hancock as Eolis glaucoides, cited in both the Atlantic and Mediterranean coasts. The study of the samples from the Portuguese coast has allowed to differentiate in the genus Calma two sympatric species coexisting in the same geographical range and living in the same habitat: C. glaucoides and C. gobioophaga. Calado & Urgorri (2002) indicate the main differences between the two species, the longest propodial tentacles of gobioophaga, the larger eyes, located immediately behind the base of the rhinophores in gobioophaga (smaller and located more behind of the base of the rhinophores in glaucoides), kidney located between the second and last group of cerata in gobioophaga (between the second and fifth or sixth group of cerata in glaucoides), smaller egg size in gobioophaga, Gobius niger eggs feeding in gobioophaga (Lepadogaster lepadogaster, L. purpurea, L. candollei, Parablennius gattorugine or P. pilicornis egg feeding in glaucoides). Very recently Prkic et al. (2014 ) have located numerous specimens of C. gobioophaga off the coast of Croatia that surely are the first record of the species for the Mediterranean Sea. These authors also performed a molecular study (COI and 16S genes) of specimens from different localities of C. glaucoides and C. gobioophaga confirming the separation of the two species.

Specimens of this species can reach up to 20 mm in length but most often measure around 10 mm. The body is rather flattened, semi-transparent and slightly yellowish or brown, but can vary according to the nutritional status of the animal and the kind of fish eggs ingested. The rhinophores and oral tentacles are short and smooth and of the same color of the body but with a band of opaque white pigment is observed in the tip. The eyes are large and are located directly behind the base of the rhinophores. The cerata are gathered in 7-10 groups on both sides of the back and with 3-4 cerata per group, with the anterior two groups located in front of the heart area. The cerata are short and with the same color of the body, somewhat inflated in its central area and its apex is usually whitish; within the cerata, digestive gland may be more or less dark brown color or cream. The kidney of the animal can be seen by transparency as a somewhat thick cord that runs through the body from the second pair of cerata to the last. The foot is wide and in the anterior zone has a pair of thin, finger-like propodial tentacles. The tail is short and is usually covered by the last group of cerata.

This newly described species generally lives in shallow water, below the stones. It is frequently found with high gregariousness, up to 70 specimens located under the same stone. It feeds on eggs of several species of the Gobiidae fish family, such as Gobius niger and G. cobitis (Calado & Urgorri, 2002; Prkic et al 2014.). The spawn is also laid on the underside of stones in the form of a fine scalloped and irregularly spiralled cord, with white eggs measuring 127 microns.


  • gobioophaga = that eats fish eggs of the genus Gobius

Due to its recent description there are very few records from the presence of this species. After its description, from specimens of the Portuguese coast, it has been cited recently in Galicia (Spain) and on the coast of Croatia (Prkic et al. 2014). Oldest records from another species of Calma, C. glaucoides from Ireland, the British coast and, by Roscoff, in France could probably represent Calma gobioophaga. In Catalonia it has been reported from L’Escala and Begur.

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

Similar species
Calma glaucoides, with shorter propodial tentacles, smaller eyes more distant from the rear of the rhinophores, shorter digestive gland, larger eggs, and feeds on Lepadogaster and Parablennius eggs.


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

This chart displays the monthly observation probability for Calma gobioophaga based on our own records.

More pictures


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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) "Calma gobioophaga" in OPK-Opistobranquis. Published: 04/10/2013. Accessed: 05/03/2024. Available at (

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