Two new species of Neozoanthus (Cnidaria, Hexacorallia, Zoantharia) from the Pacific

Abstract. The zoanthid genus Neozoanthus was originally described in 1972 from a single species in Madagascar. This monotypic genus was placed within its own family, Neozoanthidae, given its unusual characters of only partial sand encrustation, and an endodermal sphincter muscle combined with a brachycnemic mesenterial arrangement. Recently, undescribed specimens of Neozoanthus were discovered thousands of kilometers away in both Australia and Japan. While the phylogenetic and evolutionary aspects of Neozoanthus spp. are now somewhat well understood, the new specimens remained undescribed. Here we describe the specimens as two new species, Neozoanthus uchina sp. n. from the Middle Ryukyu Islands of southern Japan, and Neozoanthus caleyi sp. n. from the waters around Heron Island, on the Great Barrier Reef in Australia. Both species can be distinguished from each other and the type species, Neozoanthus tulearensis, by their distributions, oral disk colors, and average numbers of tentacles. Additionally, each species appears to have subtle differences in their cnidae. The division of Japanese and Australian specimens into two species is strongly supported by recently reported phylogenetic data. The discovery and description of these two species highlights how little is known of zoanthid species diversity in the Indo-Pacific.