Flabellina affinis (Gmelin, 1791)
WoRMS Taxonomic Information
Current classification
| Superdomain | Biota |
|---|---|
| Kingdom | Animalia |
| Phylum | Mollusca |
| Class | Gastropoda |
| Subclass | Heterobranchia |
| Infraclass | Euthyneura |
| Subterclass | Ringipleura |
| Superorder | Nudipleura |
| Order | Nudibranchia |
| Suborder | Cladobranchia |
| Superfamily | Fionoidea |
| Family | Flabellinidae |
| Genus | Flabellina |
| Species | Flabellina affinis (Gmelin, 1791) |
Taxonomic note: The classification of the Flabellinidae had remained fairly stable until in 2017 a series of works appeared (Furfaro et al., 2017; Korshunova et al., 2017) that intended to clarify the status of the Flabellinidae family. The main objective of the paper by Furfaro et al. was to molecularly characterize the Mediterranean species while the paper by Korshunova et al. wanted to delve into the phylogenetic relationships between various members of the Flabellinidae family and the other families of aeolidaceans.
Both works were based on the combination of molecular and morphological techniques and, in fact, do not offer very different results, but differ on the size and origin of the studied samples and, mainly, on the interpretation of the results. After the appearance of the paper by Furfaro et al., many Mediterranean species of the genera Calmella, Flabellina and Piseinotecus were grouped under the common genusFlabellina, but had certain problems with some species that did not fit well with the proposed classification (e.g,Flabellina babai) , discovered that the Mediterranean and Atlantic populations ofFlabellina ischitana correspond to two different cryptic species, and noted the problems of the cryptic group formed by Calmella cavolini / Flabellina confusa / Piseinotecus gaditanus, indicating the need for further studies to clarify their status.
Curiously, these studies were being carried out practically in parallel by the group of Korshunova et al. but on a much wider sample of species that included specimens from the Arctic, North Atlantic, Pacific and Indian Oceans. This second paper confirms the polyphily of the family Flabellinidae, but the interpretation of these results becomes a real revolution for the taxonomy of the aeolidaceans, especially for the family Flabellinidae.
Both papers show that there are two well differentiated clades (groups) in the Flabellinidae: species like Coryphella pedata and similars, with cerata that come directly from the back, and species like Flabellina affinis and similars, with cerata of each group coming from a stalk or pod. Although Furfaro et al. consider the species of both clades belonging to the genusFlabellina within the family Flabellinidae, Korshunova et al. distinguishes two families: Coryphellidae and Flabellinidae sensu stricto, also creating many different genera in these families to include the species they study. Its taxonomic proposal, curiously, solves the problems found by Furfaro et al.
In a way, both papers complement to each other, although in the paper by Korshunova et al. it is evident the lack of studies on tropical flabellinid species and those from southern America and Africa, so the subject has not been settled. The proposal to create new genera to collect small groups of species, instead of multispecific genera, seems to be the trend in some of the phylogenetic works of recent years. A detailed discussion of this exciting controversy can be found at (https://opistobranquis.info/en/flabellinidae/).
- Doris affinis Gmelin, 1791 (original)
- Eolidia flabellina Vérany, 1846
Description
This is a species that can reach up to 50 mm in length. The body is translucent and the overall coloration is pink-purple, the foot of a slightly lighter shade. Oral and propodial palps are also coloured pink-purple. The rhinophores are thin, annulated and of the same color of the body. The apex of oral palps and rhinophores is usually whitish. The cerata are long, narrow and pointed, semitransparent, with a light violet color except the upper third, that is somewhat darker; usually with a whitish apex. Within each cerata there is a diverticula of the digestive gland seen as a thin reddish-brown cord. The cerata are gathered in 7-8 groups on both sides of the body; The cerata of each group grow up from some thick lateral appendages of the body (like pods) which in turn are subdivided into 2-3 smaller appendages, each of these having 3-4 cerata. These pods from where the cerata grow are coloured pink and in certain specimens there are little darker violet spots. The genital openings are located below the first group of cerata on the right side of the body. The foot is narrow and semitransparent.
Biology
This is one of the most colorful, abundant and easy to identify nudibranchs on European shores. As most aeolidacean nudibranchs, it feeds on hydroids, in this case of the athecate genus Eudendrium (E. ramosum, E.racemosum ), on whose arborescent colonies it is usually localized, often sharing food and substrate with another very frequent aeolidacean, Cratena peregrina. It is generally found between 5 and 20 m. deep. F. affinis usually spawns on the hydrarian forming an undulating pink cord laid somewhat wildly; the cord width is about 0.5 mm and the eggs 90 microns in diameter are placed tightly inside of it. It is not uncommon to find specimens with parasiting copepods, easy distinguishable on the animal’s dorsum, between the cerata, because of their egg sacks forming a very apparent white lace.
Etymology
- Flabellina derived of Latin Flabellum, meaning “fan”.
- Affinis, means “alike, resemblant, similar”.
Distribution
This is one of the most frequent and widely distributed opisthobranchs found in European waters. In the Iberian Peninsula it has been cited in all coasts but in the Cantabrian coast and Galicia. It has also been cited in the Balearic and Canary islands. In Catalonia it is present in all rocky shores, wherever its food grows.
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Similar species
Paraflabellina ischitana is very similar but cerata lack the intense purple coloration on the tips. Edmundsella pedata has smooth rhinophores and cerata grow directly on the body (not from dorsal pods or stubs) and the tips of cerata are not purple.
Abundance
| Western Mediterranean: | ★★★★☆ |
| Eastern Mediterranean: | ★★★★☆ |
| Atlantic Ocean: | ★★☆☆☆ |
This chart displays the monthly observation probability for Flabellina affinis based on our own records.
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Further reading
Cite this article as:
Ballesteros, M., Madrenas, E. & Pontes, M. (2025) "Flabellina affinis" in OPK-Opistobranquis. Published: 17/05/2012. Accessed: 03/09/2026. Available at (https://opistobranquis.info/en/?p=597)
