Fjordia insolita

Fjordia insolita  (Garcia-Gomez & Cervera, 1989)

Fjordia insolita by José Carlos García Gómez

Taxonomy
 

Superdomain

Biota  

 

Kingdom

Animalia  

 

Phylum

Mollusca  

 

Class

Gastropoda  

 

Subclass

Heterobranchia  

 

Infraclass

Euthyneura  

 

Subterclass

Ringipleura  

 

Superorder

Nudipleura  

 

Order

Nudibranchia  

 

Suborder

Cladobranchia  

 

Superfamily

Flabellinoidea  

 

Family

Coryphellidae  

 

Genus

Fjordia  

 

Species

Fjordia insolita  (Garcia-Gomez & Cervera, 1989)

 
 Classification according to Bouchet et al. (2017)
Taxonomic source: World Register of Marine Species (AphiaID: 1047415).

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/).

This species was originally described within the genus Flabellina although some of its morphological traits (type of oral palps, rhinophores, papillae in the cardiac area and laminar expansions in the back) indicated that possibly it was not the most appropriate taxonomic location. Korshunova et al. (2017), based on morphological data alone, placed Flabellina insolita within the new genus Fjordia as F. insolita (García-Gomez & Cervera, 1989). We consider molecular analisis are mandatory to definitively clarify its generic status.

Synonyms

  • Flabellina insolita  Garcia-Gomez & Cervera, 1989

Description
This species can reach a size of 16 mm in length. The color of the body is hyaline white with opaque white lines that run along the back of the oral tentacles, rhinophores, back and sides of the body. The oral palps are widened at their base in a very characteristic way. The rhinophores are long and thin, and 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 traits 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. There are up to 8 groups of ceratas on each side of the body. The ceratas are long and thin, semitransparent, and allow to see the digestive branch inside, coloured orange or reddish and with a granular texture, almost completely filling the interior of the cerata; the apex of the cerata are semitransparent, without pigmentation of any kind. The foot has hooked propodial palps in its anterior area and the tail is relatively long and sharp.

Biology
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.

Etymology

  • 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.

Distribution
It is a very rare species that so far is only known from the Tarifa area (Strait of Gibraltar) (García-Gómez & Cervera, 1989) and the Portuguese coast of the Algarve (Ortea & Espinosa, 1998).

Known georeferenced records of the species: Fjordia insolita
Sources:
: OBIS
: GROC 2010-2011
: Enric Madrenas
: João Pedro Silva
: Bernard Picton
: GBIF.ORG
: OPK
: VIMAR
: Manuel Ballesteros.
: M@re Nostrum
: Altres fonts
: Marine Regions

References for the species: Fjordia insolita

Abundance

    Western Mediterranean:
    Eastern Mediterranean:
    Atlantic Ocean:

More pictures

Bibliography

Further reading

Cite this article as:

José Carlos García Gómez (2012-2018) "Fjordia insolita" in OPK-Opistobranquis, Published: 30/12/2015, Accessed: 14/11/2018 at (https://opistobranquis.info/en/L0kj2)

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