A New Epizoanthus Species (Cnidaria: Anthozoa: Epizoanthidae) Associated with the Gastropod Mollusk Guildfordia triumphans from Southern Japan.

ABSTRACT

From previous research, it is known that hermit crabs predominantly dwell in vacated gastropod shells. Several epibiotic taxa are known to live on gastropod shells inhabited by hermit crabs, including some species of the zoantharian genus Epizoanthus. Although many previous taxonomic studies have focused on hermit-crab-associated Epizoanthus species, and have resulted in the description of several species, gastropod-associated species have received comparatively much less attention. At least five Epizoanthus species associated with gastropods have been formally described, but some species have not been found or examined since their original description. In Japan, specimens on the gastropod mollusk Guildfordia triumphans have been found and examined in previous studies, but no formal taxonomic conclusions were made. In this study, we formally describe Epizoanthus rinbou sp. n. from southern Japan based on molecular phylogenetic analyses combined with morphological observations. Epizoanthus rinbou sp. n. is located within an Epizoanthus clade consisting of species associated with gastropods, hermit crabs, sea urchins, and barnacles, as well as non-associated Epizoanthus species. The present study highlights the utility of molecular phylogeny for understanding the diversity and relationships of gastropod-associated Epizoanthus species.