Redescription and range extension of the sea anemone Exocoelactis actinostoloides (Wassilieff, 1908), with revision of genus Exocoelactis (Cnidaria, Anthozoa, Actiniaria)

Among specimens of sea anemones collected from the tropical western Pacific on cruises under the auspices of the Institut de Recherche pour le Développement (IRD) and the Muséum national d’Histoire naturelle, Paris, are some we identify as Exocoelactis actinostoloides (Wassilieff, 1908). We synonymize under this name the species described as Cymbactis maxima Wassilieff, 1908, and Exocoelactis valdiviae Carlgren, 1928. The first two were described from one specimen each, collected at unspecified depths of Sagami Bay, Japan; the latter was based on five specimens reportedly collected off the coast of East Africa at depths of 741 to 823 m. We examined 23 specimens collected in New Caledonia, the Philippines, and Palau from depths of 175 to 480 m. Thus, we extend the geographical and bathymetric range of this species. These specimens allowed us to resolve discrepancies in the definition of the genus Exocoelactis concerning completeness and sterility of the mesenteries: the stronger partner of the mesenterial pairs may be complete and may be sterile.