Onchidoris pusilla

Onchidoris pusilla (Alder & Hancock, 1845)

Onchidoris pusilla by Bernard Picton

Taxonomy
 

Superdomain

Biota  

 

Kingdom

Animalia  

 

Phylum

Mollusca  

 

Class

Gastropoda  

 

Subclass

Heterobranchia  

 

Infraclass

Euthyneura  

 

Subterclass

Ringipleura  

 

Superorder

Nudipleura  

 

Order

Nudibranchia  

 

Suborder

Doridina  

 

Infraorder

Doridoidei  

 

Superfamily

Onchidoridoidea  

 

Family

Onchidorididae  

 

Genus

Knoutsodonta  

 

Species

Knoutsodonta pusilla   (Alder & Hancock, 1845)

 
 Classification according to Bouchet et al. (2017)
Taxonomic source: World Register of Marine Species (AphiaID: 1259492).
Synonyms

  • Doris pusilla Alder & Hancock, 1845

Description
This species of doridacean can reach a size of 9-10 mm in length. The body is oval shaped and very flattened, nearly circular when the animal is at rest. The body color is dark brown because of numerous densely packed colour patches covering it. Near the edge of the mantle there are usually whitish stains. All the dorsal mantle is covered with small conical brown tubercles, although frequently their base is whitish; tubercles located near the margin of the mantle are smaller. As in other species of Onchidoris, the mantle is very espiculous with elongated transversally laid spicules in the center, and diagonally laid near the edges, but this spiculation is not apparent due to the pigmentation of the body. The rhinophores are white, short, with up to nine lamellae and do not have a high rhinophoric sheath; the rhinophoric orifice has two tubercles in an anterior-internal position and in lateral-external position. The gill consists of up to nine small simply pinnate leaves arranged in a circle on the back of the dorsum, almost completely surrounding the anus; The gill crown is also tuberculate, with two tubers in anterior position and another one closing the gill circle. The gill leaves colour is white, like rhinophores, but Mediterranean specimens are pigmented dark brown with scores, like the mantle, although the spine is coloured cream. The cephalic region under the mantle does not differentiate oral palps; the cephalic veil border is usually pigmented brown. The foot is whitish with tiny brown spots; internal viscera can be glimpsed through the center of the foot as a reddish-brown stain.

Biology
The specimens of this species tend to live both in the intertidal and subtidal stratum, often under stones and on the bryozoan colonies from which they feed. There have been cited, as food or substrate,  the following species of bryozoans: Callopora spp., Escharella immersa, Microporella ciliata, Escharoides coccineus, Porella concinna and Schizomavella linearis (McDonald & Nybakken, 1999). The spawn consists of a semitransparent narrow cord with white eggs, wound in a tight flat spiral with up to 9 turns; sometimes there are two egg spirals surrounded by a unique exterior cord. The spawns have been observed in the month of May.

Etymology

  • Onchidoris, tuberculate Doris.
  • Doris, a sea nymph in Greek mythology.
  • Pusilla, from Latin “pusillus”, petty, trifling, insignificant, very small.

Distribution
There are few known references of this species. It has been observed in the Norwegian coast, in the British Isles, and in the Atlantic Iberian Peninsula shores. In the Iberian Coast it has been cited in the Cantabrian Sea and the Strait of Gibraltar.

Known georeferenced records of the species: Onchidoris pusilla
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

Abundance

    Western Mediterranean:
    Eastern Mediterranean:
    Atlantic Ocean:

More pictures

Bibliography

Further reading

Cite this article as:

Ballesteros, Manuel, Enric Madrenas, Miquel Pontes (2012-2018) "Onchidoris pusilla" in OPK-Opistobranquis, Published: 17/05/2012, Accessed: 19/06/2018 at (https://opistobranquis.info/en/JuGvP)

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