Aplysia parvula

Aplysia parvula (Guilding in Morch, 1863)

Aplysia parvula by Enric Madrenas




































Aplysia parvula  Mörch, 1863

 Classification according to Bouchet et al. (2017)
Taxonomic source: World Register of Marine Species (AphiaID: 138757).
Taxonomic note: According to a recent paper by Golestani et al (2019) all Mediterranean sea hares classified as Aplysia parvula are Aplysia punctata. However, considering there are many “morphotypes” of Aplysia parvula and Aplysia punctata with more than evident morphologic differences (we have observed many types of small Aplysia in our sampling dives), we stick to the former denomination until further studies are published on this group.


  • Aplysia allochroa Bergh, 1908
  • Aplysia anguilla Sowerby G.B. II, 1869
  • Aplysia atromarginata Bergh, 1905
  • Aplysia australiana Clessin, 1899
  • Aplysia concava G.B. Sowerby I, 1833
  • Aplysia intermedia Farran, 1905
  • Aplysia japonica Sowerby G.B. II, 1869
  • Aplysia lobata Bergh, 1908
  • Aplysia norfolkensis G. B. Sowerby II, 1869
  • Aplysiopsis juanina Bergh, 1898
  • Syphonota elongata Pease, 1860

Mediterranean specimens of this species usually have a size of about 20 mm, although a maximum length of 60 mm is quoted in the literature. The general colour of the body is reddish brown or greenish-brown due to a thick brown lattice defining pink or green polygonal areas with an irregular white spot inside. They also tend to have some white spots formed by clusters of white spots scattered over the head, neck, behind the base of the rhinophores, sides of the body and parapodia. The head, as in all species of the genus is very well developed, with a long neck that joins the body; cephalic tentacles are wound in longitudinal direction and its top is usually black, the rhinophores are auriculate, short and thin, with a black pointed end. In front of and slightly outside of the base of the rhinophores the eyes can be located inside of a slightly protruding whitish circular area. On the right side of the body there is a spermal groove that goes from the mantle cavity to near the base of the rhinophore. The parapodia are short and are fused near the tail; the edge of the parapodia is bordered by a wide black band, sometimes interrupted by white spots. The dorsal mantle that covers the viscera is very thin and has a large oval foramen through which the shell can be observed. Under the right edge of the shell some thick black granules corresponding to the purple gland could be observed. The pinkish gill is semitransparent and it is fusioned to the front area of the mantle cavity. The yellowish shell is partially covered by the mantle, spiralled at the apex only while the rest is flattened; is calcified only in the central area, the rest of it being flexible. When evaginated, penis is pink and shaped like a flattened spoon with a basal sheath. The foot is pink but the front and rear ends which are black, may have white granulations on the lateral margins. The tail end is narrow and pointed.

Aplysia parvula is a species that is widely distributed throughout the upper infralittoral floor and has occasionally been cited in circalittoral bottoms. It is generally found associated with different red algae as Sphaerococcus coronopifolius, Laurencia obtusa and Delisea pulchra, as it feeds on them, and acquires its colour. In the absence of red algae it can also feed on green algae, in that case specimens use to be of greenish tones. It may accumulate secondary metabolites, of the type of furanones, from the red algae it feeds on, it is cited to be occasionally predated by certain species of pycnogonids and nemerteans in the Pacific Ocean. As in other opisthobranchs, A.parvula is hermaphrodite and, as happens with the other species of the genus, several specimens (4-5) mate together, copulating in chains: the individual in front of the chain receives sperm from the next, thereby acting as a female, intermediate specimens of the chain give sperm to the speciment in front of them while receiving sperm from the animal on their back, acting both as male and female, and last in the chain gives sperm to the animal in front of it, being the only one acting as male. Shortly after mating the fertilized specimens lay their eggs, forming of a very convoluted bead of about 0.6 mm in diameter with numerous pink or reddish eggs of 80-100 microns in diameter. It can be confused with juveniles of Aplysia punctata or Aplysia fasciata because the parapodia of these species lack the black rim of the parapodia. In case of very dark specimens of A.parvula where the black rim of parapodia is not visible, they can be told apart because juveniles of the other Aplysia tend to have a red or light brown coloured body.


  • Aplysia. From the Greek word meaning “dirty”
  • Parvula. Latin word meaning “very small”

This species was described in 1863 on the island of St. Thomas in the West Indies and later findings since then have shown that it is a circumtropical distribution species, mostly found between 40°N and 40°S. In the Atlantic it has been located in the intertidal of Brazil, in the Gulf of Mexico, Curaçao, Puerto Rico, Florida coast, the British Isles, in both the Atlantic and Mediterranean shores of the Iberian Peninsula, in the Balearic islands, in the Canary islands, Madeira, Açores, and off coast in South Africa. In the Pacific it has been located in the Gulf of California, Japan, Korea, Hawaii islands, Marshall islands, Indonesia, Australia, New Zealand and the Red Sea. In the Mediterranean it has been found both in the eastern basin (Turkey, Greece, Israel) and the western basin (Malta, Naples, Gulf of Taranto, Ligurian sea, Tangier). It has been postulated that Mediterranean colonization of this species has it origin on a Lessepsian migration through the Suez Canal, a fact that has not yet been demonstrated. In the Catalan coast is is often found living on soft stiped red algae; it has been cited in Cala Sant Antoni and Es Caials (Cadaques), Roses, L’Escala, Illes Medes, Cala Aiguafreda and Cala Aiguablava (Begur), Tossa de Mar and Blanes.

Known georeferenced records of the species: Aplysia parvula
: GROC 2010-2011
: Enric Madrenas
: João Pedro Silva
: Bernard Picton
: Manuel Ballesteros.
: M@re Nostrum
: Altres fonts
: Marine Regions


    Western Mediterranean: ★★☆☆☆
    Eastern Mediterranean: ★☆☆☆☆
    Atlantic Ocean: ★★☆☆☆
[wpbi_chart type="bar" id="1" height="250" /]

This chart displays the monthly observation probability for Aplysia parvula based on our own records.

More pictures


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Further reading

Cite this article as:

Ballesteros, M., Madrenas, E. & Pontes, M. (2023) "Aplysia parvula" in OPK-Opistobranquis. Published: 15/05/2012. Accessed: 22/04/2024. Available at (https://opistobranquis.info/en/?p=359)

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