Placida tardyi

Placida tardyi   (Trinchese, 1873)

Placida tardyi @ France by Pascal Girard




































Placida tardyi  (Trinchese, 1874)

 Classification according to Bouchet et al. (2017)
Taxonomic source: World Register of Marine Species (AphiaID: 141567).

  • Laura tardy Trinchese, 1873

The specimens of this species can reach a size of about 15 mm. The body is elongated and slender. The base color of the body is yellowish or whitish, but it is masked by the numerous branches of the digestive gland, olive green, that darken the body in dorsal vision. These hepatic branches also branch out to the rhinophores, the anal peduncle, the head and the sides of the body. The cardiac area is coloured in white and has the shape of an elongated spot. There are also usually small brown scores and somewhat larger opaque white spots on the flanks of the body. The head is small. The rhinophores are long and thin, they are longitudinally grooved and have a reddish coloured pointed tip. The anal orifice is located in front of the cardiac area, at the end of a prominent papilla. The genital orifice is located right behind the right rhinophore and there is an elongated reddish stain from this point to the middle of the body side. There are numerous cerata on the back, which are arranged tightly; their shape is elongated and tappered. Within them the pale green digestive gland is visible forming a non-branched duct. There is a purple stain at the apex of each cerata with some white granulations clustered together right below. The foot is somewhat broad in front and the tappered tail is thin. The foot is yellowish with fine brown or reddish scores forming two coloured longitudinal bands (Trinchese, 1879: Lam XV, Figs 1 and 2). This species has been confused on several occasions with Placida viridis. Cervera et al. (1988) restablished the species Placida tardyi and clearly stated the differences with Placida viridis.

This species, like other sacoglossans, lives on green algae and marine phanerogams, where it is unnoticed because of its colouration. Gascoigne & Sordy (1980) reported its presence on the chlorophycean Bryopsis sp. and Schmekel & Portmann (1982) in meadows of Posidonia oceanica and Zostera. In both cases it was cited as Placida viridis. The last two authors indicate that it feeds on Bryopsis sp. and also describe its spawn as a flat ring or spiral with white eggs 40-60 microns in diameter.


  • Placida. From Latin “placeō”, please, satisfy. Also means placid, gentle, quiet, still, calm, mild, peaceful.
  • Tardyi. Possibly dedicated to the French admiral Louis Marie Françoise Tardy de Montravel, (1811-1864), who circumnavigated the world with Dumont d’Urville in 1837. Later he studied the South American coastal regions and also the Japanese and Sea of Okhotsk coasts. In 1854 he took posession of New Caledonia for France.

This species inhabits the western Mediterranean and nearby Atlantic areas. In the Mediterranean it has been reported in its type locality Genoa, Italy (Trinchese, 1873), in the port of Livorno, Italy (Gascoigne & Sordi, 1980) and in the gulf of Naples, Italy (Schmekel & Portmann, 1982). Outside the Mediterranean Sea it has only been observed in the coast of Cadiz, Spain (Cervera et al., 1988) and in Sagres, in southern Portugal (Calado et al., 2003).

Known georeferenced records of the species: Placida tardyi
: 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: ★☆☆☆☆

This chart displays the monthly observation probability for Placida tardyi based on our own records.

More pictures


    Ballesteros, M., E. Madrenas, and M. Pontes. 2023. OPK - Opistobranquis. (
    Calado, G., M. Malaquias, C. Gavaia, J. L. Cervera, C. Megina, B. Dayrat, Y. Camacho, M. Pola, and C. Grance. 2003. New data on opisthobranchs (Mollusca: Gastropoda) from the southwestern coast of Portugal. Boletín Instituto Español de Oceanografía 19 (1-4): 199-204.
    Cervera, J. L. 1988. Notaspideos, ascoglosos y nudibranquios, (mollusca : opisthobranchia) de Andalucía Occidental con algunas referencias al litoral del Estrecho de Gibraltar : estudio faunístico y sistemático. Tesis Doctoral. Universidad de Sevilla.
    Cervera, J. L., J. C. García, and J. A. Ortea. 1988. A New Species Of The Genus Hermaea Gastropoda Opisthobranchia Sacoglossa And Redescription Of Two Rare Sacoglossans Of The European Malacofauna. Iberus 8 (2). 1988. 215-224.
    Cervera, J. L., G. Calado, C. Gavaia, M. A. E. Malaquías, J. Templado, M. Ballesteros, J. C. García-Gómez, and C. Megina. 2004. An annotated and updated checklist of the opisthobranchs (Mollusca: Gastropoda) from Spain and Portugal (including islands and archipelagos). Boletín Instituto Español de Oceanografía, 20 (1-4): 1-111. L.
    Gascoigne, T., and M. Sordi. 1980. A redescription of Placida viridis (Trinchese, 1873) (Gastropoda: Ascoglossa). Journal of Conchology 30: 167-179.
    Long, S. J. 2006. Bibliography of Opisthobranchia 1554-2000. Bayside Books & Press, Tustin, CA, U.S.A. 672p.
    McDonald, G. 2009. Bibliographia Nudibranchia. 2nd Online Edition, Annotated. 1072 pp  Institute of Marine Sciences, University of California, Santa Cruz. (
    Parera, A., M. Pontes, X. Salvador, and M. Ballesteros. 2020. Sea slugs (Mollusca, Gastropoda, Heterobranchia): the other inhabitants of the city of Barcelona (Spain). Butlletí de la Institució Catalana d’Història Natural, 84: 75-100.
    Pontes, M., X. Salvador, A. Parera, G. Álvarez, and M. Ballesteros. 2021. Biodiversity in anthropized marinas. The case of the Barcelona Forum bathing area (Spain), Monografies de la Societat Catalana d’Història Natural. Institució Catalana d’Història Natural, Barcelona.
    Rufray, X., P. Girard, S. Le Bris, T. Menut, C. Santarelli, and X. Salvador. 2021. Liste commentée des limaces de mer de la lagune de Thau, Hérault. Les cahiers de la fondation Biotope. 36: 1–189.
    Schmekel, L., and A. Portmann. 1982. Opisthobranchia des Mittelmeeres, Nudibranchia und Saccoglossa. Fauna e Flora del Golfo Napoli. Springer-Verlag, Berlin.
    Templado, J., and R. Villanueva. 2010. Checklist of Phylum Mollusca. pp. 148-198 In Coll, M., et al., 2010. The biodiversity of the Mediterranean Sea: estimates, patterns, and threats. PLoS ONE 5(8):36pp.
    Trainito, E., and M. Doneddu. 2014. Nudibranchi del Mediterraneo, 2nd. ed. Il Castello.
    Trinchese, S. 1873. Descrizione di alcuni nuovi Eolididei del Porto di Genova. Memorie della R. Accademia delle Scienze dell’ Istituto di Bologna, series 3, 4:197-203.
    Trinchese, S. 1877. Æolididae e famiglie affini del Porto di Genova. Part 1. Anatomia, fisiologia, embriologia delle Phyllobranchiae, Hermaeidae, Aeolididae, Proctonotidae, Dotonidae del Porto de Genova. Atti della R. Università di Genova. Atlas, pp. 1-94, pls. 1-35.
    WoRMS Editorial Board. 2023. World Register of Marine Species. WoRMS. (

    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, M., Madrenas, E. & Pontes, M. (2023) "Placida tardyi" in OPK-Opistobranquis. Published: 20/10/2014. Accessed: 28/02/2024. Available at (

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