Shallow-water brachycnemic zoanthids (Cnidaria: Hexacorallia) from Taiwan: A preliminary survey

Zoanthids are benthic cnidarians commonly seen in shallow coral reef and subtropical marine ecosystems, and are increasingly being utilized as research subjects for marine products and biodiversity studies. However, their distributions and overall species diversity remain relatively unknown except for in a few regions of the world, including southern Japan. Here, for the 1st time, the shallow-water diversity of zoanthids of the suborder Brachycnemina, which primarily includes zooxanthellate species, was examined in Taiwanese waters. Species diversity surveys conducted at coral reef (Kenting and Lyudao) and non-reefal (Keelung) locations revealed 12 zoanthid species (Acrozoanthus australiae, Isaurus tuberculatus, Zoanthus gigantus, Z. kuroshio, Z. sansibaricus, Z. aff. vietnamensis, Palythoa heliodiscus, P. mutuki, P. tuberculosa, Palythoa sp. tokashiki, unknown Palythoa spp., and another unknown zoanthid), most of which are new records for Taiwan. All 3 locations had totals of 7-10 species present, with the 2 coral reef locations resembling locations with coral reefs in Okinawa (e.g., by the presence of Z. kuroshio, P. heliodiscus, Palythoa sp. tokashiki), while the zoanthid community at Keelung was more similar to zoanthids observed at subtropical Shikoku, Japan (e.g., by the presence of Z. aff. vietnamensis and large Z. gigantus colonies). It is possible that the unknown Palythoa specimens constitute 1 or more species new to science, and further investigation of these zoanthids is needed. It is hoped that the species lists provided in this study will help provide a basis for future zoanthid research in Taiwan.