Flabellina ischitana

Flabellina ischitana (Hirano & Thompson, 1990)

Flabellina ischitana 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: Flabellinoidea  Bergh, 1889
Family: Flabellinidae  Bergh, 1889
Genus: Flabellina  Voigt, 1834
Species: Flabellina ischitana  Hirano & Thompson, 1990

Taxonomic note: In their last work about this group, Furfaro et al. (2017) concluded that “Unexpectedly high values of genetic distance were observed between Mediterranean and Atlantic populations of F. ischitana. Individuals morphologically identified as F. ischitana formed two well supported clades in all phylogenetic trees and showed a minimum COI p-distance of 12.5%. These results suggest that Mediterranean and Atlantic populations of F. ischitana may represent indeed two ‘cryptic species’. We provisionally named these two taxa as the “Mediterranean” and the “Atlantic” F. ischitana, but according to the type locality of the species (Ischia Island, Mediterranean Sea) F. ischitana can be considered as the valid name for the Mediterranean species. The description of the Atlantic form as a new species is currently in progress and will be provided in a future work.”

This species of aeolidacean can reach a size of up to 25 mm long. The body color is homogeneous pink or purple-violet except on the tips of rhinophores and oral tentacles, which are white, and the cerata, semitransparent and inside which it can be seen the red, orange or brown digestive gland, depending on the specimens. The rhinophores have from 12 to 19 thin circular lamellae. In larger specimens there can be up to 9 groups cerata on each side of the back, generally well separated from each other. The cerata of each group come from a common stalk of the same color of the body, as in other species of Flabellina, which can be further divided in 2 to 3 secondary stalks in the groups cerata located to the front of the animal. The cerata are thin and have a whitish sharp tip, where  the cnidosac can be seen. The genital and anal orifices are located on the right side of the body, the genital pore located slightly before the first ceratal stalk and the anal pore somewhat ahead of the second group of cerata. The foot is narrow, of the same color of the body and, with two small triangular propodials tentacles in the front side. The tail is short and narrow.

This is an active aeolidacean often found in shallow water, where its food, the athecate hydrozooan Eudendrium (E. racemosum, E. glomeratum) lives, but it has also been observed down to a depth of 35 m (Hirano & Thompson, 1990). It can share food and substrate with Flabellina affinis, a somewhat larger species with which it can easily be confused. Cervera et al. (1998) indicate the main differences between these two species. The spawn of F. ischitana is shaped like a thick cord arranged in irregular loops containing pink eggs about 70 microns in diameter.


  • Flabellina. Diminutive of Latin “flabellum”, fan.
  • Ischitana. From the island of Ischia, in the Tirrenian Sea, in the gulf of Naples; where this nudibranch was first cited.

F. ischitana is a southern European species living both in the Eastern and Western Mediterranean basins. In the Iberian Peninsula it has been found in Portugal, the Strait of Gibraltar and all along the Mediterranean coast. In Catalonia it is a relatively common species which is recorded in different localities of the Costa Brava such as Cadaques, Cala Aiguablava (Begur), L’Escala and Tossa de Mar.

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

References for the species: Flabellina ischitana

    Portugal: Ortea and Espinosa (1998), Calado et al. (1999, 2005), Wirtz and Debelius (2003). Andalucía (Atl.): Cervera, López-González and García-Gómez (1998). Gibraltar: Cervera, López-González and García-Gómez (1998). Andalucía (Med.): Sánchez Tocino, Ocaña and García (2000a), Ocaña et al. (2000). Catalunya: Ballesteros (datos no publicados) [Cap Falcó, Punta del Gat, Punta del Bisbe de Roses, Tossa de Mar], M@re Nostrum [Cala Rovellada (Colera) 5/2006, Cap Ras (Llançà) 11/1998, Bau de S’Arnella (El Port de la Selva) 6/2000].

    General: Cattaneo-Vietti, Chemello, & Giannuzzi-Savelli, 1990:161[P]; Parent, 1994:211[P]

    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 Flabellina ischitana based on our own records.

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Further reading

Cite this article as:

Ballesteros, Manuel, Enric Madrenas, Miquel Pontes et al. (2012-2017) "Flabellina ischitana" in OPK-Opistobranquis, Published: 17/05/2012, Accessed: 18/12/2017 at (https://opistobranquis.info/en/wVP1p)

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