The sands of time: rediscovery of the genus Neozoanthus (Cnidaria: Hexacorallia) and evolutionary aspects of sand incrustation in brachycnemic zoanthids
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- Reimer, J.D., Hirose, M., Irei, Y. et al. Mar Biol (2011) 158: 983. doi:10.1007/s00227-011-1624-8
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The zoanthid family Neozoanthidae (Anthozoa: Hexacorallia: Zoantharia) was described in 1973 from Madagascar as a monogeneric and monotypic taxon, and never reported again in literature. In 2008–2010, numerous zoanthid specimens fitting the morphological description of Neozoanthus were collected in the Ryukyu Islands, Okinawa, Japan, and the Great Barrier Reef (GBR), Australia. Utilizing these specimens, this study re-examines the phylogenetic position of Neozoanthidae and analyzes the evolutionary history of sand incrustation in zoanthids through phylogenetic and ancestral state reconstruction analyses. Specimens were colonial, partially incrusted with large, irregular sand and debris, zooxanthellate, and found from the intertidal zone to depths of approximately 30 m. Phylogenetic results utilizing mitochondrial 16S ribosomal DNA and cytochrome oxidase subunit I sequences show the presence of two Neozoanthus species groups, one each from Japan and the GBR. Unexpectedly, the molecular results also show Neozoanthus to be very closely related to the genus Isaurus, which as a member of the family Zoanthidae, is not sand incrusted. These results suggest that during evolution zoanthids can acquire and lose the ability to incrust sand with relative rapidity.