Facelina dubia

Facelina dubia (Pruvot-Fol, 1948)

Facelina dubia by Bernard Picton

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: Aeolidioidea  J.E. Gray, 1827
Family: Facelinidae  Bergh, 1889
Genus: Facelina  Alder & Hancock, 1855
Species: Facelina dubia  Pruvot-Fol, 1948

This species can reach a remarkable size, it has been cited up to 38 mm in length. The body is translucent and suggests much of the internal organs that are coloured creamy white. On the head there is an orange stain, corresponding to the buccal bulb, that can be seen by transparency as well as the esophagus that can be observed as a dark red lace curved to the left between the base of the rhinophores and slightly behind them. There are small white spots scattered throughout the animal’s back and head. Oral tentacles are thin and elongated, they are also translucent with white spots, the same with the rhinophores, that lack any lamellae. The eyes can be seen on the inner posterior basal region of the rhinophores. The cerata are very long and thin and are arranged in seven groups on each side of the body. The first 4 groups are composed of 2 or more rows of cerata and the first group is located far ahead, levelled up with the rhinophores. The cerata length of each row increases from the outermost one (which is shorter) to the innermost (which is longer). The cerata are also semitransparent, they have superficial white stains and the digestive diverticulum can be clearly seen inside, as a fine greenish lace. The apex of the cerata are white. The genital opening, very apparent and funnel-shaped, is located below the last two rows of the first group of cerata on the right, while the anus is located slightly behind, below the second group of cerata on the right. The propodial tentacles in front of the foot are triangular.

F. dubia feeds on athecate hydroids of the genus Podocoryne and Tubularia over which it also spawns. This is a very active species that, when disturbed extends all cerata trying to resemble an actiniarian with a clearly defensive purpose. In European Atlantic coasts it is a common finding on submerged ropes where hydrozoans grow, also in soft substrates with traces of molluscs shells that are colonized by hydroids. Mediterranean specimens rarely exceed 20 mm in length. The spawn is a coiled cord with white eggs of about 100 microns.


  • Facelina, from Latin, means “lined face”.
  • Dubia, del Latin, means “doubtful”.

This is an European species that inhabits the Atlantic waters from Norway to the Bay of Biscay. In the Mediterranean it has been cited in the Gulf of Naples and the Catalan coast. Common in the beachfront of Barceloneta (Barcelona), on a gravel bottom 10-15 m deep with abundant bivalve shell remains and other anthropogenic debris.

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

References for the species: Facelina dubia

    Catalunya: Ballesteros, Ortea, Vallve, & Martinez, 1993:123.

    General: Nordsieck, 1972:79 as Acanthopsole dubia; Just & Edmunds, 1985:132[P]; Picton & Brown, 1981:265; Picton & Morrow, 1994:124[P]; Pruvot-Fol, 1954b:391; Schonenberger & Schonenberger, 1961:293; Thompson, 1988:320; Thompson & Brown, 1984:151[P] as Facelina dubia

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


    Western Mediterranean:
    Eastern Mediterranean:
    Atlantic Ocean:
This chart displays the observation probability for Facelina dubia based on our own records.

More pictures


Further reading

Cite this article as:

Ballesteros, Manuel, Enric Madrenas, Miquel Pontes et al. (2012-2017) "Facelina dubia" in OPK-Opistobranquis, Published: 20/11/2012, Accessed: 18/12/2017 at (https://opistobranquis.info/en/WKVLd)

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