Cuthona willani

Cuthona willani Cervera, García-Gómez & López-González, 1992

Cuthona willani by Cervera et al (1992) by OPK

Up to 12mm in length. The body color is translucent yellowish white, pigmented yellow or slightly garnet, with iridescent reddish spots that are distributed over different parts of the body, such as the sides of the head and the right side of the pericardial area, sometimes absent in juveniles. The rhinophores and oral tentacles have the same length and appearance, and are cylindrical, long, with iridescent red spots at the base, a characteristic reddish enlargement in the middle area, and hyaline yellow apices. Cerata appear in oblique rows that form 10-13 groups, exhibiting a reddish-yellow hue and two enlargements: a fairly evident subapical one, delimited by two reddish rings and another enlargement close to the base. The apex of the cerata is hyaline yellow and may have a rounded shape if the animal is relaxed, or a pointed shape if the animal is stressed, with the cnidosac extended. The base of the cerata allows to see the interior digestive gland, which is dark brown in color, but at the base of the cerata it is seen as reddish brown. The foot has rounded corners on its anterior part and a relatively long and pointed tail on the rear. The anus is acleioproct and the genital pore is located under the second row of cerata on the right side.

It lives in rocky infralittoral bottoms. The egg spawn consists of a spiral of 2-3 whorls forming a cup with triangular section walls and a rough surface. Each capsule contains a single spherical egg about 97-117 microns in diameter.


  • Willani. In honor to Dr. Richard C. Willan (1952-) from the University of Queensland (Australia) for his excellent contributions to the knowledge of sea slugs.

Known only from the coasts of Huelva and the South of Portugal, in 1995 its presence was reported in the Canary Islands and in 2001 in Témara, on the Atlantic coast of Morocco.

Known georeferenced records of the species: Cuthona willani
: 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 Cuthona willani based on our own records.

More pictures


    Ballesteros, M., E. Madrenas, and M. Pontes. 2023. OPK - Opistobranquis. (
    Calado, G., and V. Urgorri. 1998. Additions and new data on Portuguese Opisthobranchs. Bollettino Malacologico 35 (5- 8): 97-102.
    Cervera, J. L., J. C. García-Gómez, and P. J. López-González. 1992. A new aeolid (Gastropoda: Nudibranchia) from the Atlantic coasts of the Southern Iberian peninsula. The Veliger 35(4): 330-337.
    Cervera, J. L., J. C. García-Gómez, F. J. García García, and J. Díaz Pavón. 2011. Familia Tergipedidae in Gofas S, Moreno D, Salas C. Moluscos marinos de Andalucía. Vol. II. Servicio de Publicaciones e Intercambio Científico, Universidad de Málaga.
    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.
    Garcia, F. J., and H. Bertsch. 2009. Diversity and distribution of the Gastropoda Opisthobranchia from the Atlantic Ocean: A global biogeographic approach. Scientia Marina. 73: 153–160.
    García-Gómez, J. C. 2002. Paradigmas de una fauna insólita; Los moluscos opistobranquios del estrecho de Gibraltar (Serie Ciencias) 20: 397 pp. Instituto de Estudios Gibraltareños. Algeciras, Cádiz, Spain.
    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. (
    Moro, L., J. Ortea, J. J. Bacallado, A. Valdés, and J. M. Pérez Sánchez. 1995. Nuevos Aeolidáceos (Gastropoda, Nudibranchia) para la fauna de Canarias. Revista de la Academia Canaria de Ciencias 7 (2, 3 and 4): 63-75.
    Ortea, J., M. Caballer, and L. Moro. 2001. Primeros datos sobre un complejo de especies alrededor de Cuthona willani Cervera, García & López, 1992 (Mollusca: Nudibranchia) en la Macaronesia y Marruecos. Revista de la Academia Canaria de Ciencias XIII (4): 101-112.
    Ortea, J. A., L. Moro, J. J. Bacallado, and R. Herrera. 2001. Catálogo actualizado de los Moluscos Opistobranquios de las Islas Canarias. Revista de la Academia Canaria de Ciencias. 12: 105–136.
    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) "Cuthona willani" in OPK-Opistobranquis. Published: 19/01/2021. Accessed: 07/06/2023. Available at (

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