The hermaphroditic sea anemone Anthopleura atodai n. sp (Anthozoa: Actiniaria: Actiniidae) from Japan, with a redescription of A. hermaphroditica

A new species of internally brooding sea anemone, Anthopleura atodai, is described from the middle to northern Pacific coasts of Honshu, Japan. This species attaches to mussels or in rock crevices of the higher tidal zone. This is the second hermaphroditic species and fourth internally brooding species of Anthopleura to be reported; it is distinguished from other members of Anthopleura by a combination of the following features: brooding its young, synchronously hermaphroditic, S-shaped basitrichs in filaments, 40 to 68 tentacles, verrucae in the proximal part of the column larger than those in the distal part, cobalt-blue spot at the distal end of each siphonoglyph. Anthopleura hermaphroditica, the species that most closely resembles A. atodai, is redescribed to clearly differentiate it from A. atodai and to resolve questions about its taxonomy and identity.