Reimer JD, Sinniger F, Fujiwara Y, Hirano S, Maruyama T. 2007. Morphological and molecular characterisation of Abyssoanthus nankaiensis, a new family, new genus and new species of deep-sea zoanthid (Anthozoa:Hexacorallia: Zoantharia) from a north-west Pacific methane cold seep
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Publication
The order Zoantharia (= Zoanthiniaria, Zoanthidea) remains one of the most taxonomically neglected
anthozoan groups, primarily owing to the difficulty of examining the internal morphology of sand-encrusted zoanthids, upon which classification has been largely based until very recently. Additionally, relatively few zoanthid species (all belonging to the genus Epizoanthus) have been properly described from the deep-sea. Numerous individuals of an unidentified sediment-encrusting zoanthid-like species were observed and sampled during a Shinkai 6500 deep-sea submersible dive at a methane cold seep (depth 3259 m) off Muroto at the Nankai Trough, Japan. Unlike previously described deep sea zoanthids, Abyssoanthus nankaiensis, gen. et sp. nov. (Abyssoanthidae fam. nov.) was found to be non-colonial, free-living (non-commensal), and, uniquely, on mudstone in the vicinity of a methane cold seep. Morphologically, A. nankaiensis, gen. et sp. nov. is characterised by its relatively uniform polyp diameter from oral to aboral end with 19–22 mesenteries. Additionally, DNA (mitochondrial 16S rDNA and mitochondrial cytochrome oxidase c subunit I DNA) sequences obtained from these samples also unambiguously place this specimen in a previously undescribed and new family within the order Zoantharia. This is the first reported zoanthid species from a methane cold seep or other so-called ‘extreme’ environment, and the first molecular characterisation of any such deep-sea zoanthid.
