Mediterranean Octocorallia: description of Clavularia carpediem n. sp. and synonymy of Clavularia crassa and C. ochracea on etho-ecological grounds

A new stoloniferan octocoral from the Mediterranean (Morocco) is described under the name Clavularia carpediem and critically compared with C. marioni Von Koch, 1891 and C. arctica (Sars, 1861). A thorough redescription of the latter species is given. The recent discovery that the common rock-dwelling colonies belonging to a species hitherto referred to as C. ochracea Von Koch, 1878 incubate their eggs on the outside of the polyps, a rather unusual fact among Octocorallia, leads to the synonymy of this species with C. crassa (Milne Edwards, 1848), so far considered a rare species living exclusively as an epibiont on the Mediterranean sea-grass Posidonia oceanica.