Aeolidiella alderi

Aeolidiella alderi (Cocks, 1852)

Aeolidiella alderi by Pontes, Miquel










































Aeolidiella alderi  (Cocks, 1852)

 Classification according to Bouchet et al. (2017)
Taxonomic source: World Register of Marine Species (AphiaID: 138710).

  • Aeolidiella soemmeringii Bergh, 1882
  • Aeolidiella soemmeringii var. mediterranea Bergh, 1885
  • Eolidia soemmeringii Leuckart, 1828
  • Eolis alderi Cocks, 1852 (original)

It is an aeolidacean that can measure up to 30 mm in length. The body is white but the head and the back usually have a light orange pigmentation on the surface. Oral palps are semi-transparent and pigmented orange at the tip, the intensity of the color deppends on the specimens. Both rhinophores grow very close together on the head, they are relatively short and smooth and they look like the somewhat longer oral palps. The eyes can be well appreciated in the rear area of the base of the rhinophores. The most characteristic trait of the species of this genus is the large number of cerata that homogeneously cover the back of the animal, with no apparent separation between the different groups. There are 12 to 13 groups of cerata on each side of the body in the largest specimens, the cerata of the first group located far ahead, its insertion in the body can be even ahead of the base of the rhinophores. The cerata are slightly curved into the body, they are somewhat flat at the base and sharpened apically, where the cnidosac could be clearly seen. The digestive gland can be seen through the semitransparent tegument of the cerata as a solid or wavy mass colored brown or dark olive green. In some specimens the general coloration of the body is very clear, creamy white, because the digestive gland has this color. The end of the larger cerata could be slightly pigmented in orange. The first group of cerata are smaller and are usually quite depigmented because the digestive gland inside the cerata only occupies their base. The foot is quite wide and semitransparent and in its anterior zone has a pair of short triangular propodial tentacles whose tip could be slightly pigmented in orange. At the back zone the foot forms a short, narrow tail, extending below the last cerata.

This species lives in shallow waters, on the underside of stones in the intertidal and upper subtidal zone. It feeds on different species of actiniarians, the following have been cited: Actinothoe anguicoma, A.sphyrodeta, Aiptasia mutabilis, Anemonia viridis, Bunodactis verrucosa, Cereus pedunculatus, Diadumene cincta, Metridium senile, Parastephanauge paxi, Sagartia elegans, S.troglodytes, Sagartiogeton laceratus and S.undatus. Marin & amp; Ros (1991) cited the presence of symbiont and photosynthetically active zooxanthellae algae in the body tissues of this species, that were acquired by the nudibranch from the actiniarians it preys on. The spawn is composed of a heavily scalloped and inward-cord that contains numerous white eggs about 200 microns in diameter (Schmekel&Portmann, 1982). The animals lay the eggmass on the lower side of the stones. The eggs of this species have direct development, with no free larval stage. As in other species of the same family, some specimens may be parasitized by copepods that lay their eggs between the cerata of the nudibranch.


  • Aeolidiella refers to an Aeolidia (another genus of the same family Aeolidiidae) of a smaller size.
  • alderi: honors J. Alder, british opisthobranch specialist from XIX century, highly renowned and, along with Hancock, author of the famous monograph on british nudibranchs (Alder, J. &. Hancock, A. 1845-1855. A monograph of the British nudibranchiate Mollusca: with figures of all the species. Pt. 1-7. Ray Society, London).


This is a strictly European species found from the shores of the Mediterranean to the North Sea. It has been cited in all coastal areas of the Atlantic and Mediterranean Iberian Peínsula. In the Catalan coast it has been observed in Portlligat (Cadaqués), Cala Fosca (Palamos), Cala Santa Cristina (Lloret), Cala Sant Francesc and Punta de Santa Anna (Blanes) and Cubelles.

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

References for the species: Aeolidiella alderi

    Cantabria: Ortea (1977c), Ballesteros (1980a). Galicia: Ortea (1977c), Urgorri and Besteiro (1983, 1984), Rolán (1983). Portugal: García-Gómez et al. (1991), Calado et al. (1999, 2003). Andalucía (Atl.): Cervera and García (1986). Gibraltar: García-Gómez (1982, 2002), García-Gómez et al. (1989). Andalucía (Med.): Sánchez Tocino, Ocaña and García (2000a). Levante: Templado (1982b, 1983, 1984), Ballesteros et al. (1986), Marín and Ros (1987, 1991). Catalunya: Ros (1975, 1978b), Ballesteros (1980, 1984, 1985), M@re Nostrum [Cala Rovellada (Colera) 2006, Cala del Paller (Calonge) 1999]. Baleares: Ballesteros (1981a, 1985), Ros (1981b), Ballesteros, Álvarez and Mateo (1986). Canarias: Odhner (1931), Pérez Sánchez, Ortea and Bacallado (1990), Pérez Sánchez and Moreno (1990), Pérez Sánchez, Bacallado and Ortea (1991), Moro et al. (1995, 2003), Ortea et al. (2001).

    General: Barletta, 1981:119; Brown, 1981a:294; Brown & Picton, 1979:23; Cattaneo-Vietti, Chemello, & Giannuzzi-Savelli, 1990:187[P]; Cesari, 1990:[P]; Colgan, 1914:178; Farran, 1909:4; Garstang, 1890:433; ICZN, 1985:165; Just & Edmunds, 1985:138[P]; Odhner, 1932:42; Perrone, 1983b:138; Picton & Morrow, 1994:130[P]; Riedl, 1983:327; Sabelli, Giannuzzi-Savelli, & Bedulli, 1990:448; Schmekel, 1970:155; Tardy, 1969a:7 Thompson & Brown, 1976:162; 1984:161[P]; Vayssiere, 1913a:300; Vicente, 1981:79; Walton, 1908:229

    Sources: Cervera et al., 2004, Ballesteros, 2007 & 2016, McDonald, 2006 and other sources.

Similar species
Spurilla neapolitana shares habitat and appearance. Cuthona granosa similar to juveniles of A.alderi.


    Western Mediterranean:2 out of 5 stars
    Eastern Mediterranean:1 out of 5 stars
    Atlantic Ocean:3 out of 5 stars

This chart displays the monthly observation probability for Aeolidiella alderi based on our own records.



More pictures


Further reading

Cite this article as:

Ballesteros, Manuel, Enric Madrenas, Miquel Pontes (2021) "Aeolidiella alderi" in OPK-Opistobranquis. Published: 16/05/2012. Accessed: 14/06/2021. Available at (

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