A systematic revision of Edwardsiidae (Cnidaria, Anthozoa)

Abstract. Difficulties in addressing relationships among sea anemones are explored in the context of a revision of the family Edwardsiidae. This family has been important in discussions of relationships within Zoantharia (Cnidaria, Anthozoa), but has been poorly characterized. Genera within Edwardsiidae are characterized by a mosaic distribution of a few key characters whose actual distribution is not well understood; generalized and idealized morphology, rather than the actual distribution of characters, has been previously used to delimit genera. Microanatomy of muscles and the body wall, qualitative and quantitative information about muscle shape, and nematocyst size are combined with 18S rDNA sequences in a cladistic analysis. The results demonstrate that some traditional diagnostic features support groups different from those previously recognized. Character support is identified for several previously proposed taxa or clades, including the genus Edwardsiella and a clade containing Nematostella and Drillactis. Edwardsiidae and several of its genera are monophyletic; however, groups within the subfamily Edwardsiinae require revision and recircumscription. The genus Edwardsia is paraphyletic, and these data do not resolve Edwardsia species into monophyletic groups.