Tenellia genovae

Tenellia genovae (O’Donoghue, 1929)

Tenellia genovae by Enric Madrenas
Class: Gastropoda Cuvier, 1797
Subclass: Heterobranchia J.E. Gray, 1840
Clade: Euthyneura Spengel, 1881
Clade: Nudipleura Wägele & Willan, 2000
Order: Nudibranchia Cuvier, 1817
Suborder: Dexiarchia Schrödl, Wägele & Willan, 2001
Infraorder: Cladobranchia Willan & Morton, 1984
Parvorder: Aeolidida Odhner, 1934
Superfamily: Fionoidea Gray, 1857
Family: Fionidae  Gray, 1857
Genus: Tenellia A. Costa, 1866
Species: Tenellia genovae (O’Donoghue, 1929)

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 previously undetected species diversity.

Korshunova et al. (2017) present some phylogenies based on morphological characters (which may be parological) to reclassify this group. In addition, for molecular phylogeny they use the COI gene (not useful to separate genera) instead of i.e. the H3 gene, so the hypotheses presented are weak. For this reason we keep the last classification until the status of this species is cleared.


  • Cratena genovae O’Donoghue, 1929
  • Cuthona genovae (O’Donoghue, 1929)
  • Trinchesia genovae (O’Donoghue, 1929)

It is a small species that can reach 9-10 mm in length. The background color of the body is yellowish in many areas but this color is masked by an opaque white iridiscent pigment, especially in the dorsum, the sides of the body and the back of the head. In some specimens there may also be a diffuse bluish pigment. A very apparent yellow stripe runs through the middle back of the body, almost from head to tail. There are orange bands on the sides of the head. The oral tentacles are semi-transparent and short and their tips are orange. The rhinophores are also semitransparent but its surface is iridescent white and usually there is an orange subapical band; in the lower third of the rhinophores, the absence of white or orange pigment forms a narrow band that is darker than the rest of rhinophore. The eyes are at the base and slightly behind the rhinophores. There are 4-5 groups of cerata on each side of the body, the first one consisting of three rows of cerata, the other groups have a single row. The cerata are slightly fusiform, quite narrow at the base and have a pointed tip. The color of the digestive gland in the cerata is dark brown and it looks granular although this colour is masked by the rather dark iridescent blue pigment of the anterior face surface. The apex of the cerata is semitransparent and has 1 or 2 circular bands coloured cream. The foot is transparent and is slightly broadened on the anterior zone, but without forming propodial palps.

Because of its small size, this species tends to be unnoticed among the algae and hydrarians where it is commonly found, on little illuminated rocky walls. It feeds on hydrarians of the genus Obelia, Dynamena, Halecium and Sertularella. The spawn is a cord coiled in a single turn containing white eggs about 100 microns in diameter.


  • Genovae refers to the city of Genoa (Italy)

It is an anfiatlantic species as it has been cited in the Caribbean (Costa Rica) and in the Canary Islands, also in all European Atlantic and Mediterranean coasts. In the Iberian Peninsula it has been found in all coastal areas of Spain and Portugal, also in the Balearic islands. In Catalonia it has been cited in various localities of the Costa Brava: Cala Sant Antoni and Es Caials (Cadaques), Cala Aiguafreda (Begur), Cala Mateua (L’Escala), Llafranc, Tossa de Mar, Cala Santa Cristina (Lloret), Blanes, Mataro and Port l’Estany (L’Ametlla de Mar).

Known georeferenced records of the species: Tenellia genovae (z-200).
: GROC 2010-2011 : VIMAR
: Enric Madrenas : Manuel Ballesteros.
: João Pedro Silva : M@re Nostrum
: Bernard Picton : Other sources
: GBIF.ORG : Marine Regions

References for the species: Tenellia genovae

    Cantabria: Ortea (unpubl. data). Portugal: García-Gómez et al. (1991), Calado et al. (1999). Andalucía (Atl.): Cervera and García (1986). Gibraltar: García-Gómez (1983, 2002). Andalucía (Med.): Ballesteros et al. (1986), Sánchez Tocino, Ocaña and García (2000a). Levante: Templado (1982b, 1983, 1984), Ballesteros et al. (1986), Marín and Ros (1990). Catalunya: Ros (1975, citada como Trinchesia foliata), Ros (1978b, 1985a, citada como Trinchesia), Ros & Altimira (1977, citada como Trinchesia), Ballesteros (1980, citada como Trinchesia, 1985), Pereira & Ballesteros (1982, citada como Trinchesia), Martín et al. (1990), Domènech et al. (2002). Baleares: Ballesteros, Álvarez and Mateo (1986). Canarias: Malaquias and Calado (1997, as C. cf. genovae), Moro et al. (1995, 2003), Ortea et al. (2001, 2003).

    General: Bouchet, 1977:235 as Trinchesia genovae; Picton & Morrow, 1994:102[P]; Picton & Wilson, 1984:349; Riedl, 1983:329; Schmekel & Portmann, 1982:250[P]; Thompson, 1988:272; Thompson & Brown, 1984:122[P] as Cuthona genovae

    Sources: Cervera et al., 2004, Ballesteros, 2007, McDonald, 2006 and other sources.


        Western Mediterranean:2 Stars
        Eastern Mediterranean:1 Stars
        Atlantic Ocean:1 Stars
This chart displays the observation probability for Tenellia genovae
based on our own records.

More pictures


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, Manuel, Enric Madrenas, Miquel Pontes et al. (2012-2017) "Tenellia genovae" in OPK-Opistobranquis, Published: 17/05/2012, Accessed: 19/10/2017 at (http://opistobranquis.info/en/jIMNS)

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