Abstract
Edwardsianthus England, 1987 is a genus of Edwardsiidae, a family of burrowing and worm-like sea anemones characterized by lacking four mesenteries in the first cycle and containing only one type of nematocysts in nemathybomes. Until now, this genus has accommodated only two species since its establishment and has been recorded only from Indo-West Pacific regions. In this study, six species are reported from Japan: two are previously known species, E.pudicus (Klunzinger, 1877) and E.gilbertensis (Carlgren, 1931); four are new species, E.carbunculus sp. nov., E.sapphirus sp. nov., E.smaragdus sp. nov., and E.amethystus sp. nov. Based on these results, the diagnostic features of the genus are revised.