Trinchesia granosa

Trinchesia granosa  Schmekel, 1966

Trinchesia granosa by Schmekel & Portmann (1982)










































Trinchesia granosa  Schmekel, 1966

 Classification according to Bouchet et al. (2017)
Taxonomic source: World Register of Marine Species (AphiaID: 750609).

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. Within Fionidae, obtained results demonstrated the need of developing a new classification as previous classifications (for instance, separating Catriona, Cuthona and Trinchesia as distinct taxa) were inconsistent with the resulting phylogeny. Analyses also recover a clade (Tenellia) that includes all members of the genera Tenellia, Trinchesia, Phestilla, Catriona and the majority of described and undescribed Cuthona species. New genera Rubramoena, Abronica and Tergiposacca are proposed to group other species. This molecular study also suggests that Fionidae is rich in cryptic species complexes, difficult to separate by traditional taxonomic characters, and a great previously undetected species diversity.
A few months later Korshunova et al. (2017) take up the study of the phylogeny of the Tergipedidae and using not only molecular data but also morphological and ontogenetic data they severely criticise the work by Cella et al. (2016), proposing to reinstate the families Calmidae, Eubranchidae, Fionidae, Tergipedidae, Cuthonidae, Cuthonellidae and Trinchesiidae, the latter being the most abundant in specific taxa. They also reinstate the genera Catriona, Diaphoreolis, Phestilla and Trinchesia that in the paper by Cella et al. (2016) had been included in the genus Tenellia. Korshunova et al. also describe a new genus, Zelentia that includes Z. pustulata (type species Eolis pustulataAlder & Hancock, 1854), Z. fulgens (MacFarland, 1966) and a new species from the Barents Sea, Z. ninel, indicating important p-distances among the three species (between 10.49% and 13.83%). All previous genera, Korshunova et al. (2017) consider them within the family Trinchesiidae. They also question the validity of the Rubramoena genus of Cella et al.
The position of WoRMS is conservative, maintaining the families Cuthonidae, Calmidae, Cuthonellidae, Eubranchidae, Fionidae, Pseudovermidae, Tergipedidae and Trinchesiidae within the superfamily Fionoidea. The European species that, until recently, were considered as Cuthona, WoRMS considers them within the genus Trinchesia, as T.albopunctata, T.caerulea, T.foliata, T.genovae, T.granosa, T.ilonae, T.miniostriata and T.ocellata. Rubramoena is also considered a valid genus in WoRMS. These opinions are those that we accept in OPK while no other more conclusive data are available.


  • Tenellia granosa (Schmekel, 1966)
  • Cuthona granosa (Schmekel, L., 1966)

Body elongated, translucent white and can measure up to 11 mm in length. The head, body, rhinophores and oral tentacles are covered with fine opaque white dots, absent on the foot and cerata. Rhinophores measure a quarter of the length of the body, are smooth and digitiform and coloured orange in their distal half. Oral tentacles are half the size of the rhinophores and their distal half is also colored orange. Cerata arranged in 9 rows along each side of the body, each row with a maximum of 4 or 6 cerata. Digestive gland is brown and is visible through the skin of the cerata, which are dotted with brown, most densely in the subapical region, below the cnidosac, which is large and white. The anus and nephroproct are located just in front of the innermost cera of the third row, on the right side of the body. The gonopore is found under the first row of cerata, also on the right side of the animal. The foot has rounded propodial tentacles, and the end of the tail is not covered by cerata.

The egg-spawn consists of an ellipsoid or reniform shape, with white eggs about 0.12mm in diameter. Larvae are not planktonic so metamorphosis takes place inside the egg. Hatching takes place after 18 days. Trinchesia granosa feeds on Podocoryne carnea.


  • Trinchesia. In honor of Professor Salvatore Trinchese (1836-1897), Italian opisthobranchiologist, Professor of Zoology at Bologna University and successor of Paolo Panceri as Professor of Comparative Anatomy at the University of Napoli.
  • Granosa. Derived from Latin granum, grain.

Species cited by Schmekel in the Gulf of Naples in 1966. There are no certified records from other locations, although there are many records of similar specimens, such as juveniles of Aeolidiella alderi, which should be studied carefully.

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

Possibility of confusion
Some juveniles of Aeolidiella alderi are very similar to Trinchesia granosa at first glance, since they have the tips of the rhinophores and oral tentacles colored orange, however, the foot is wider, the propodial tentacles triangular and pointed, some cerata have the tips slightly colored in orange, the large eyes located at the base of the rhinophores and the lighter colour of the first ceratal ring (due to the still poor development of the digestive gland inside), as well as the insertion of the first cerata ring in front of the rhinophores, all of which are typical characteristics of A. alderi, allow them to be distinguished.


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

This chart displays the monthly observation probability for Trinchesia granosa based on our own records.

More pictures


    Ballesteros, M., E. Madrenas, and M. Pontes. 2023. OPK - Opistobranquis. (
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    Cattaneo-Vietti, R., R. Chemello, and R. Giannuzzi-Savelli. 1990. Atlas of Mediterranean Nudibranchs. La Conchiglia, Rome, Italy.
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    Korshunova, T., A. V. Martynov, and B. E. Picton. 2017. Ontogeny as an important part of integrative taxonomy in tergipedid aeolidaceans (Gastropoda: Nudibranchai) with a description of a new genus and species from the Barents Sea. Zootaxa 4324 (1): 1-22.
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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:

Pontes, Miquel (2023) "Trinchesia granosa" in OPK-Opistobranquis. Published: 17/05/2012. Accessed: 27/02/2024. Available at (

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