A survey of the genera Sarcodictyon Forbes, 1847, and Rolandia Lacaze-Duthiers, 1900, (Anthozoa: Octocorallia) in the North-eastern Atlantic and the Mediterranean

Sarcodictyon catenatum Forbes, 1847, is a common species in the Atlantic and the Mediterranean. However, often it has been mistaken for Rolandia coralloides Lacaze-Duthiers, 1900. On the basis of British and Mediterranean material we studied the main characters for distinguishing S. catenatum. We consider Rolandia coralloides Lacaze-Duthiers, 1900, to be a valid species and we assign to it all the material named Rolandia rosea by S. Weinberg (1978). Furthermore, a histological study confirmed that R. coralloides typically forms groups of polyps embedded in a common coenenchyme. Therefore, the possibility of transferring R. coralloides from Stolonifera to Alcyonacea is discussed. Evagorgia rosea Philippi, 1842, is here considered to be a nomen dubium.