Elysia timida

Elysia timida (Risso, 1818)

Elysia timida by Enric Madrenas
Taxonomy
Class: Gastropoda  Cuvier, 1797
Subclass: Heterobranchia  J.E. Gray, 1840
Clade: Euthyneura  Spengel, 1881
Clade: Panpulmonata  Jörger et al., 2010
Clade: Sacoglossa  von Ihering, 1876
Subclade: Plakobranchacea  Jensen, 1996
Superfamily: Plakobranchoidea  J.E. Gray, 1840
Family: Plakobranchidae  J.E. Gray, 1840
Genus: Elysia  Risso, 1818
Species: Elysia timida (Risso, 1818)

Synonyms

  • Elysia viridis var. lactea Bergh, 1880
  • Notarchus timidus Risso, 1818 (original)

Description
The body can reach up to 20 mm in length. The head is elongated and has long thin rolled rhinophores, on whose base, and on the outer side, are the eyes. The parapodia are triangular. The cardiac area protrudes slightly on the anterior back of the body, right in the area where the parapodia originate. On the back of the body there are thin veins that converge towards the back area of the heart. The foot is grooved and has two lobes in the anterior part. The background color of the body is white with abundant red and black dots on the head and on the outer side of the parapodia. The inside of the parapodia is dark green, a color shared by a strip that runs along each side of the body, below the insertion of the parapodia and the external basal third of each rinophore.

Biology
This saccoglossan lives in shallow rocky bottoms with abundant photophilic algae as Padina pavonica, Acetabularia acetabulum, Halopteris and Corallina. In these communities, specimens are usually very active and, when they do, they move in a very characteristic way, moving the parapodia and the rhinophores back and forth rhythmically. It feeds on unicellular chlorophycean algae Acetabularia acetabulum (Acetabularia crenulata in the Caribbean), from which retains the functional chloroplasts inside the saccoglossan tissues, thus obtaining an important source of organic nutrients via photosynthesis. However, due to the abundance of specimens observed in the Catalan coast in winter (sometimes more than 100 animals can be observed in a single dive), a period in which the thalli of A. acetabulum are reduced to stipes of resistance, it is possible that it feeds from another species of algae. E. timida has direct development, lacking pelagic larval stage. In the body of E. timida there have been found compounds of the group of polipropionates, of known ichthyotoxic activity, probably synthethised by the animal (Gavagning et al. 1994).

Etymology

  • Elysia. It is a girl’s name of Latin origin, derived from the word Elysium, which in mythology is the home of the blessed, known as the “Elysian fields”. The name Elysia also means “God’s oath” in Hebrew. Frieder Sauer comments that Elysia means heavenly.
  • Timida. From latin “timidus” means timid, shy.

Distribution
Traditionally considered endemic to the Mediterranean as it has been cited everywhere, from the Eastern coasts like Turkey, Israel or Greece to the Western coasts like Italy or Spain. Elysia timida is present in the tropical western Atlantic (it has been found in Cuba and Florida), hence showing an amphi-Atlantic distribution, but possibly due to recent introduction of human origin (see Carmona et al., 2011). It has been also found in São Tomé (Wirtz & Anker, 2009) and in Cape Verde (Rolán, 2005). In the Iberian Peninsula it has been collected in the coast of Granada, in the Eastern coast from Almeria to the Mar Menor and in the Catalan and Balearic coasts. In the Catalan coast it is widespread in all locations where its food, the unicellular alga Acetabularia acetabulum, is found.

Known georeferenced records of the species: Elysia timida (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

Abundance

        Western Mediterranean:4 Stars
        Eastern Mediterranean:4 Stars
        Atlantic Ocean:1 Stars
This chart displays the observation probability for Elysia timida
based on our own records.

More pictures

Video

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) "Elysia timida" in OPK-Opistobranquis, Published: 14/05/2012, Accessed: 27/06/2017 at (http://opistobranquis.info/en/bwUbf)

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