Ancula gibbosa
(Risso, 1818)

Suborder: DORIDINA
Family: Goniodorididae


From the western Mediterranean around the northern Atlantic coast to the White Sea, Greenland & Iceland and across the New England coast of N. America. If A. pacifica is the same species it also occurs on the west coast of North America.


UPPER RIGHT: Mumbles, Swansea, Wales, United Kingdom, March 1993. Specimens found at low tide (0.1m) on larger stones in lowest Fucus serratus belt. PHOTO: Daniel Geiger.
LOWER RIGHT: White-spotted colour form, Vancouver, British Columbia, Canada. PHOTO: C. Gibbs.

Grows to about 30mm. Translucent white, usually with three longitudinal orange lines on body and orange tipped rhinophores, gills and papillae. Rarely, as in this photo, the orange is replaced with opaque white. Usually found on compound bryozoans but Picton, on his website, suggests they may in fact feed on Entoprocta [= Kamptozoa], minute animals thast can be found living on bryozoans and other sessile animals. Ancula pacifica from west coast of North America is identical in colour and Thompson (1976) considers it a synonym of A. gibbosa.

See my comments below.
See message on white-spotted colour form.
See message on Ancula pacifica.

• Risso, A. (1818). Memoire sur quelques gasteropodes nouveaux, nudibranches et tectibranches observes dans la mer de Nice (1). Journal de Physique de Chimie, d'Histoire naturelle et des Arts, Paris 87: 368-377.

Authorship details
Rudman, W.B., 2000 (March 24) Ancula gibbosa (Risso, 1818). [In] Sea Slug Forum. Australian Museum, Sydney. Available from

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