Redescription of the Sea Anemone Exocoelactis actinostoloides (Cnidaria: Anthozoa: Actiniaria) Based on a Topotypic Specimen Collected from Tokyo Bay, Japan

抄録

We collected a specimen of Exocoelactis actinostoloides (Wassilieff, 1908) from the type locality of the species in October, 2012. The name of Ex. actinostoloides has been misapplied to a species of Entacmaea (Ehrenberg, 1834) around the Indo-Pacific region in many works, including scientific reports, although some authors have noted the error. A true specimen of Ex. actinostoloides has not been found in Japanese waters since the collection of the type specimen at Jogashima, Kanagawa Prefecture, in 1904. Here, we redescribe Ex. actinostoloides based on the present specimen from the opposite side of the Uraga Strait, and analyze the phylogenetic position of this species within Actiniaria based on mitochondrial 12S and 16S rDNA sequence data. These are the first molecular data ever provided for the family Exocoelactinidae. The sequence data indicate that Ex. actinostoloides is a member of the superfamily Actinostoloidea, and that it is most closely related to the family Actinostolidae.