Tenellia adspersa

Tenellia adspersa (Nordmann, 1845)

Tenellia adspersa by Klas Malmberg










































Tenellia adspersa  (Nordmann, 1845)

 Classification according to Bouchet et al. (2017)
Taxonomic source: World Register of Marine Species (AphiaID: 141639).

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.


  • Embletonia grayi Kent, 1869
  • Embletonia pallida Alder & Hancock, 1854
  • Eolis armoricana Hesse, 1872
  • Eolis ventilabrum Dalyell, 1853
  • Tenellia mediterranea Costa A., 1866
  • Tenellia pallida (Alder & Hancock, 1845)
  • Tergipes adspersus Nordmann, 1845 (original)

It is a small aeolidacean that does not usually exceeds 8 mm in length. Its color can vary from whitish, creamy, brown or even black, depending on its food. On the back, head and cerata there may be small dark spots. The head has a semicircular frontal veil with lateral angles, without oral tentacles. Robust and smooth rhinophors. Cerata are scarce in number and arranged in 4-6 groups of 1-3 cerata. These are elongated, cylindrical and with a rounded tip; They are semi-transparent and the digestive gland inside is colored cream. Juvenile specimens usually have the rear cerata more developed than anterior ones.

It is an eurithermal and eurihaline species. Lives at shallow depths, often within ports, bays, estuaries and canals. It feeds on a wide variety of hydrozoans of the genera Bouganvillia, Campanularia, Laomedea, Cordylophora, Eudendrium and Obelia. It can form two types of eggs, some of 70 microns that develop planktonic larvae early and others of about 100 microns that take longer to develop and form crawling and benthic larvae.


  • Adspersa, from Latin “adspersus”, meaning “scattered”, refers to the pigment spots on the body.

It has an almost cosmopolitan distribution since it has been reported in European Atlantic waters, the Mediterranean, Japan and both coasts of North America. In Catalonia it is a very rare species. Possibly its wide distribution is due to its transport by sea as part of the encrustating fauna of the ship’s hulls.

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

References for the species: Tenellia adspersa


    Western Mediterranean:1 out of 5 stars
    Eastern Mediterranean:1 out of 5 stars
    Atlantic Ocean:1 out of 5 stars

This chart displays the monthly observation probability for Tenellia adspersa based on our own records.

More pictures

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Further reading

Cite this article as:

Ballesteros, Manuel, Enric Madrenas, Miquel Pontes (2012-2020) "Tenellia adspersa" in OPK-Opistobranquis, Published: 16/10/2014, Accessed: 19/02/2020 at (https://opistobranquis.info/en/RBFsz)

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