Tenellia ocellata

Tenellia ocellata (Schmeckel, 1966)

Tenellia ocellata by Enric Madrenas
Taxonomy
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: Fionoidea Gray, 1857
Family: Fionidae  Gray, 1857
Genus: Tenellia A. Costa, 1866
Species: Tenellia ocellata (Schmeckel, 1966)

Taxonomic note: The phylogenetic analyses performed by Cella et al. (2016) revealed that the traditional Tergipedidae family is polyphyletic and belongs to a larger monophyletic clade including members of the traditional families Eubranchidae, Fionidae and Calmidae; this was an unexpected result, since the validity of these taxa and their distinctness from the Tergipedidae was never questioned before. They proposed to join the families Tergipedidae, Eubranchidae, Calmidae and Fionidae under the name of Fionidae. Within Fionidae, obtained results demonstrated the need of developing a new classification as previous classifications (for instance, separating Catriona, Cuthona and Trinchesia as distinct taxa) were inconsistent with the resulting phylogeny. Analyses also recover a clade (Tenellia) that includes all members of the genera Tenellia, Trinchesia, Phestilla, Catriona and the majority of described and undescribed Cuthona species. New genera Rubramoena, Abronica and Tergiposacca are proposed to group other species. This molecular study also suggests that Fionidae is rich in cryptic species complexes, difficult to separate by traditional taxonomic characters, and previously undetected species diversity.

Synonyms

  • Trinchesia ocellata Schmekel, 1966
  • Cuthona ocellata (Schmeckel, 1966)

Description
The specimens can grow up to 13 mm in length. The animal body is stylized and translucent but with a yellowish-green hue. In the dorsum stands out a white longitudinal line that runs from the head, across the base of rhinophores, to the tail. On the flanks of the body also tends to have a white line, sometimes discontinuous. The oral palps are relatively short, transparent and with white pigment on the surface, but at the base, which is yellow. The rhinophores are almost as long as the oral palps and are also semi-transparent, so with a binocular lens it is possible to see the rhinophoric nerve inside. The surface of rhinophores has white spots that may be almost continuous in the front and rear sides. The eyes, inconspicuous, are located somewhat behind the base of the rhinophores. There can be up to 8 groups of cerata on each side of the body. The first two groups are symmetrical and among them there is the heart region, noticeable because of a slight prominence and because of the transparent integument, it is possible to distinguish the atrium and the ventricle and observe its contractions. There are three rows of cerata in the first group while only one row in the other groups. From the second group of cerata, the rest are asymmetric, the insertion of the right ones being a little advanced than the insertion of the left ones. In each group, the size of cerata increases from the outer side to the more internal ones. Inside each cerata, the digestive gland is brown at the base and deep red near the apex, which is yellowish. In the upper half of the epidermis of the cerata there are white spots of irregular size and shape. The foot is narrow and its anterior zone has short propodial palps coloured yellowish green. The genital orifice is located under the second row of the first group of cerata on the right side of the body.

Biology
Several species of hydrarians have been cited as substrate for T.ocellata, both thecate and athecate, like the genus Halecium, Dynamena, Sertulaella, Dicoryne, Podocoryne, Obelia and Eudendrium. They could be this species food source. Spawns have been found on colonies of the hydrarian Halecium labrosum; the spawn is an irregularly shaped transparent cord with white eggs of about 120 microns in diameter.

Etymology

  • Ocellata derives from Latin ocellus, a diminutive of oculus, eye. Refers to a simple eye common to many marine organisms, but is also used for animals with circular spots, similar to eyes.

Distribution
T.ocellata is a relatively common species that lives mainly in the Western Mediterranean, as it has been observed in the Gulf of Naples and the along the Iberian Peninsula shores, both in Spain and Portugal. In Catalonia it has been cited in several localities of the Costa Brava as Cala Sant Francesc (Blanes), Cala Santa Cristina (Lloret) and Tossa de Mar, among others.

Known georeferenced records of the species: Tenellia ocellata (z-200).
Sources:
: OBIS : OPK
: GROC 2010-2011 : VIMAR
: Enric Madrenas : Manuel Ballesteros.
: João Pedro Silva : M@re Nostrum
: Bernard Picton : Other sources
: GBIF.ORG : Marine Regions

References for the species: Tenellia ocellata

    Portugal: García-Gómez et al. (1991), Calado and Urgorri (1999), Calado et al. (1999, 2003). Gibraltar: García-Gómez et al. (1989). Levante: Templado (1982b, 1983, 1984). Catalunya: Ballesteros (1985, 1986), M@re Nostrum [Es Caials 5/2001].

    General: Cattaneo-Vietti, Chemello, & Giannuzzi-Savelli, 1990:181[P]; Perrone, 1986a:33; Riedl, 1983:329; Schmekel & Portmann, 1982:257[P]

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

Abundance

        Western Mediterranean:2 Stars
        Eastern Mediterranean:0 Stars
        Atlantic Ocean:0 Stars
This chart displays the observation probability for Tenellia ocellata
based on our own records.

More pictures

Bibliography

Bibliography based on the works by Steve Long, 2006. Bibliography of Opisthobranchia 1554-2000 and Gary McDonald, 2009. Bibliographia Nudibranchia, with later updates from other resources.

Further reading

Cite this article as:

Ballesteros, Manuel, Enric Madrenas, Miquel Pontes et al. (2012-2017) "Tenellia ocellata" in OPK-Opistobranquis, Published: 17/05/2012, Accessed: 25/09/2017 at (http://opistobranquis.info/en/HvMLu)

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