Favorinus branchialis

Favorinus branchialis (Rathke, 1806)

Favorinus branchialis by Enric Madrenas










































Favorinus branchialis  (Rathke, 1806)

 Classification according to Bouchet et al. (2017)
Taxonomic source: World Register of Marine Species (AphiaID: 139940).

  • Doris branchialis Rathke, 1806 (original)
  • Eolidia rusconii Vérany, 1846 
  • Eolis alba Alder & Hancock, 1844 
  • Eolis carnea Alder & Hancock, 1854 
  • Favorinus albidus Iredale & O’Donoghue, 1923 
  • Flabellina versicolor Costa A., 1866 
  • Matharena oxycantha Bergh in Mörch, 1871 

The largest specimens of this species can grow to more than 20 mm in length but usually it only attains around 10 mm in length. The body is transparent but internal viscera are usually masked by a series of thin opaque white marks that go from the head and along the back, where they form a band that widens near each cerata group and gets thinner in between. However, the color of this band may vary slightly depending on the size and feeding of the animals. The oral tentacles are thin and translucent, with the tip colored white. The rhinophores are wide at the base and have a very characteristic subapical globosity, their color is brown up to the globe and from there to the apex they are yellowish. The cerata are presented in 4-5 groups on each side of the body. They are relatively short and curved towards the inside part of the body and, deppending on the specimen, they can be almost completely covered with opaque white pigment or just sprayed with a few white spots. The brown digestive gland can be seen under the white zones. There may also be a brown subapical band in each cerata, while their apexes are transparent. The anterior part of the foot ends in a pair of short propodial palps.

It is a species that feeds on different species of hydroids, like Obelia geniculata and Sertularia sp. but its favorite meal are other opisthobranch spawns, such as Placida dendritica, Elysia viridis, Aplysia fasciata, Tylodina perversa, Platydoris argo and Felimida (= Hypselodoris) tricolor among others. For this reason it is not uncommon to find specimens of F. branchialis perfectly camouflaged among opisthobranchs egg ribbons. The spawn for this species is a flat spiral with numerous (up to 20,000) white eggs of about 50-70 microns in diameter.


  • Favorinus. Possibly dedicated to the gallo-roman phylosopher Favorinus de Arles (80-160) sophyst, enemy of the stoicism; only fragments of his work are known.
  • branchialis – from “branchia” = gill

F. branchialis inhabits all European Atlantic coast from Norway to the Iberian Peninsula, also the Canaries, the Azores, Madeira, the coast of Morocco and Cape Verde archipelago. It is a relatively common species in the western Mediterranean. In the Iberian Peninsula has been reported in all coastal areas, both Atlantic and Mediterranean. There are some reports from its presence in the western Atlantic (coasts of Florida, the Caribbean and Brazil coast) but confirmation is needed. In the Catalan coast it has been observed in Cadaqués, Begur, Llafranc, Tossa de Mar, Blanes, Vallcarca inner harbor (Garraf), Sitges and Cubelles.

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

References for the species: Favorinus branchialis

    Cantabria: Ortea (1977c), Fernández-Ovies (1981). Galicia: Urgorri and Besteiro (1983, 1984), Rolán (1983). Portugal: García-Gómez et al. (1991), Calado et al. (1999, 2005). Andalucía (Atl.): Cervera (unpubl. data). Gibraltar: García-Gómez (1983, 2002), García-Gómez et al. (1989), Sánchez-Moyano et al. (2000). Andalucía (Med.): Ballesteros et al. (1986), Ocaña et al. (2000). Levante: De Fez (1974), Templado (1982b, 1983, 1984), Ballesteros et al. (1986), Marín and Ros (1987). Catalunya: Ros (1975, 1978), Ballesteros (1980, 1985), Pereira & Ballesteros (1982), Domènech et al. (2002). Canarias: Ortea (1982), Pérez Sánchez, Ortea and Bacallado (1990), Pérez Sánchez and Moreno (1990), Pérez Sánchez, Bacallado and Ortea (1991), Moro et al. (1995, 2003), Ortea et al. (2001). Madeira: Wirtz (unpubl. data). Azores: Calado (2002).

    General: Bergh, 1879:566; Clark, 1984:95; Edmunds, 1964:19; Edmunds & Just, 1983:200; Edmunds & Marcus, 1977:200; Jensen & Clark, 1986:454; Marcus & Hughes, 1974:527; Marcus & Marcus, 1963:50; Odhner, 1939:81; Schmekel, 1970:146; Thompson, 1980:96 as Favorinus auritulus; Barletta, 1981:116[P]; Brown & Picton, 1979:22; Cattaneo-Vietti, Chemello, & Giannuzzi-Savelli, 1990:213[P]; Edmunds & Marcus, 1977:200; Eliot, 1910d:172; Fez Sanchez, 1974:90; Hayward, Wigham, & Yonow, 1990:722; Hoffmann, 1926:20; Marcus & Marcus, 1970a:83; McMillan, 1968:71; Nordsieck, 1972:81; Perrone, 1983b:137; Picton & Morrow, 1994:128[P]; Pruvot-Fol, 1953b:50; 1954b:400; Riedl, 1970:433; 1983:326; Schmekel & Portmann, 1982:200 [P]; Sordi & Majidi, 1956:242; Thompson, 1988:326[P]; Thompson & Brown, 1976:158; 1984:155[P]; Vicente, 1967:158; 1981:79 as Favorinus branchialis.

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

Similar species
Facelina rubrovittata, narrow body, translucent, dotted with brown with longitudinal orange lines on the back and sides of the body. Rhinophores with 4-5 annular enlargements. Cerata brown, fine and curved towards the center of the body.


    Western Mediterranean:1 out of 5 stars
    Eastern Mediterranean:0 out of 5 stars
    Atlantic Ocean:1 out of 5 stars

This chart displays the monthly observation probability for Favorinus branchialis 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, Manuel, Enric Madrenas, Miquel Pontes (2021) "Favorinus branchialis" in OPK-Opistobranquis. Published: 17/05/2012. Accessed: 25/01/2021. Available at (https://opistobranquis.info/en/atET7)

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