Tritonia nilsodhneri

Tritonia nilsodhneri Marcus Ev., 1983

Tritonia nilsodhneri by Enric Madrenas










































Tritonia nilsodhneri  Marcus Ev., 1983

 Classification according to Bouchet et al. (2017)
Taxonomic source: World Register of Marine Species (AphiaID: 141737).
Taxonomic note: This species was described for science by J. Tardy in 1963 as Duvaucelia odhneri, then it was transferred to the genus Tritonia as T. odhneri (Tardy, 1963) but then it was found that this name was already occupied by a species of Chilean Pacific Tritonia odhneri Marcus, 1959. For all these reasons, Marcus (1983), in his review of the Tritoniidae of the western Atlantic, assigned a new name for Tardy’s species, Tritonia nilsodhneri Marcus Ev., 1983, which is is actual name for this species.


  • Duvaucelia odhneri Tardy, 1963

Specimens of this species are long and narrow, with a square section body and can measure more than 30 mm when fully stretched. Its coloration is variable depending on the species of gorgonian on which are: they could be completely white, pink or dark brown. The head with an oral veil with 4-6 thin fingerings, the ones at the sides are the longest. The mouth is located at the bottom center of the head face veil. The rhinophores have a broad base and a club-shaped end, which is surrounded by short fingerings some of which are forked. The rhinophoric sheaths are narrow and of tubular type. The eyes are located at the rear base of the rhinophoric sheaths. On either side of the body there are up to 8 white and finely branched dorsal arborizations, the closer to the tail are often rudimentary. The yellowish animal viscera can be seen by transparency in lightly coloured specimens from the rhinophores’ area up to behind the third pair of dorsal arborizations. The genital papilla is on the right side, under the first dorsal arborization, while the anus is located in the same side but between the first and second arborization. The foot is widened on the rear and is pigmented white.

This species of dendronotacean lives on gorgonians of the genus Eunicella (E. singularis, E. verrucosa) but it is also found, although less frequently, on the brick coloured gorgonian Lophogorgia sarmentosa. The animals keep a perfect mimicry on the gorgonian they are living by wounding themselves on the branches so their dorsal arborizations resemble the gorgonian polyps. Spawns are laid as a transparent ribbon with white eggs, which are spirally wound on the branches of the gorgonian.


  • Tritonia. The genus Tritonia is dedicated to Triton, in Greek mythology the god of the sea, son of Poseidon and Amphitrite, portrayed as having the head and trunk of a man and the tail of a fish.
  • Nilsodhneri. In honor to Prof. Dr. Nils Hjalmar Odhner, (1884-1973), specialist on molluscs at the Swedish Museum of Natural History, Stockholm, succeded Bock as professor of invertebrate zoology and director of this museum department in 1946, until his retirement in 1949, when he was succeded by Karl Lang. However, he continued to work and published until 1968. His interest in molluscs was broad, albeit his special area concerned opisthobranchs.

T. nilsodhneri lives in the European Atlantic coasts, from the British Isles to the Iberian Peninsula and in the Mediterranean. In the Iberian Peninsula it has been found in all coastal areas both Atlantic and Mediterranean (Cervera et al. 2004). In Catalonia it has been observed in different localities of the Costa Brava like Es Caials, Cadaqués, L’Escala, Cala Aiguafreda, Cala Aiguablava, Medes Islands, Tossa de Mar, Blanes and outside the breakwater of the port of Barcelona.

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

References for the species: Tritonia nilsodhneri

    Cantabria: Ortea and Urgorri (1981a), Ávila Escartín (1993). Galicia: Ortea and Urgorri (1981a), Urgorri and Besteiro (1983, 1984), Rolán (1983). Portugal: García-Gómez et al. (1991), Calado et al. (1999, 2003). Gibraltar: García-Gómez (1983), García-Gómez et al. (1989). Andalucía (Med.): Sánchez Tocino, Ocaña and García (2000a). Levante: Templado, Talavera and Murillo (1983), Templado et al. (2002). Catalunya: Ballesteros (1987), Ávila (1993), Ballesteros (datos no publicados) [varias localidades de la Costa Brava, costa del Maresme y espigón del puerto de Barcelona], M@re Nostrum [Punta dels Tres Frares (El Port de la Selva) 5/1999, Es Caials (Cadaqués) 10/1998, Illa Mateua (L'Escala) 10/1998, Cala Aiguafreda (Begur) 5/1999]. Todas, excepto M@re Nostrum, citadas como Duvaucelia o Tritonia odhneri.

    General: Cattaneo-Vietti, Chemello, & Giannuzzi-Savelli, 1990:139[P]; Gosliner, 1987b:107[P]; Hayward, Wigham, & Yonow, 1990:708; Just & Edmunds, 1985:10[P]; Picton & Morrow, 1994:30[P]; Thompson, 1988:114[P]; Thompson & Brown, 1984:15[P]

    Sources: Cervera et al., 2004, Ballesteros, 2007 & 2016, McDonald, 2006 and other sources.


    Western Mediterranean:3 out of 5 stars
    Eastern Mediterranean:0 out of 5 stars
    Atlantic Ocean:0 out of 5 stars

This chart displays the monthly observation probability for Tritonia nilsodhneri based on our own records.

More pictures


Further reading

Cite this article as:

Ballesteros, Manuel, Enric Madrenas, Miquel Pontes (2012-2019) "Tritonia nilsodhneri" in OPK-Opistobranquis, Published: 16/05/2012, Accessed: 23/05/2019 at (

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