Fjordia insolita (Garcia-Gomez & Cervera, 1989)
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: Fjordia Korshunova, Martynov, Bakken, Evertsen, Fletcher, Mudianta, Saito, Lundin,
Schrödl & Picton, 2017
Species: Fjordia insolita (Garcia-Gomez & Cervera, 1989)
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. We hope to see new papers expanding the knowledge on the aeolidaceans soon. A detailed discussion of this exciting controversy can be found at (https://opistobranquis.info/en/flabellinidae/).
- Flabellina insolita Garcia-Gomez & Cervera, 1989
This species can reach a size of 16 mm in length. The color of the body is hyaline white in all its extension with opaque white lines that run along the back of the oral tentacles, rhinophores, back and lateral walls of the body. The oral palps are widened at their base in a very characteristic way. The rhinophores are long and thin, they are curved backwards; approximately in their middle zone they are also widened having one or several anterior sharp projections. The eyes are visible behind the base of the rhinophores. Other characteristics of the species are the presence of small papillae on both sides of the cardiac area and the existence of small transverse laminar expansions in the central area of the back from the second group of ceratas to the last. Up to 8 groups of ceratas on each side of the body. The ceratas are long and thin, semitransparent and allow to see inside the digestive branch, orange or reddish and granular that almost completely fills the interior of the cerata; the apex of the cerata is semitransparent, without pigmentation of any kind. The foot has hooked propodial palps in its anterior area and the tail is relatively long and sharp.
Almost nothing is known about the biology of the species, only that it is usually found living on hydrozoan colonies between 20 and 40 m deep.
- Fjordia, derived from Norwegian “fjord” because the type locality of Fjordia lineata is Oslofjord, and it is also very common at Gulen, in the Sognefjord, from where many samples studied by Korshunova et al. (2017) come from.
- Insolita. From Latin “insolitus”, unaccustomed, for the special anatomical traits of this animal, such as the rhinophores and oral palps with basal bulbs and papillae, and laminar expansions of the body, which make it unmistakable.
It is a very rare species that until now is only known from the Tarifa area (Strait of Gibraltar) (García-Gómez & Cervera, 1989) and the Portuguese coast of the Algarve (Ortea & Espinosa, 1998).
| : OBIS|
: GROC 2010-2011
: Enric Madrenas
: João Pedro Silva
: Bernard Picton
| : OPK|
: Manuel Ballesteros.
: M@re Nostrum
: Altres fonts
: Marine Regions
- We have no (more) pictures for Fjordia insolita
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