The known geographical distribution of the sea anemone Actinothoe sphyrodeta (Gosse) (Cnidaria, Actiniaria), hitherto generally believed to occur in the north-eastern Atlantic Ocean from the Shetland Islands to the Bay of Biscay, has been extended with new records from the Iberian Peninsula. These records comprise three from the west coast of Portugal and one from the Mediterranean coast of Spain.
The sea anemones (Actiniaria) of the north-eastern Atlantic Ocean have been closely studied for at least a century and a half, and along with those of the Mediterranean Sea, constitute perhaps the best known actiniarian fauna in the world. Furthermore, there has long been discussion of the endemicity of Mediterranean sea anemones, and of apparent overlaps between the distributions of some Atlantic and Mediterranean species. It is, therefore, of particular interest when a species thought to have a solely Atlantic or solely Mediterranean distribution is discovered on the ‘wrong’ side of the Strait of Gibraltar. The anemone Actinothoe sphyrodeta (Gosse) was hitherto generally believed to occur only in north-western Europe, with a range from the Shetland Islands to the Bay of Biscay (e.g. Fischer, 1890; Manuel, 1981). It is reported here for the first time from Portugal and from the Mediterranean coast of Spain.