First seep-dwelling Desbruyeresia (Gastropoda: Abyssochrysoidea) species discovered from a serpentinite-hosted seep in the Southeastern Mariana Forearc

ABSTRACT

The South Chamorro Seamount (13°47'N, 146°00'E) on the southeastern Mariana Forearc is one of a series of serpentine mud volcanoes in the area, and hosts an active fluid seepage area on its summit. During a recent research cruise three specimens of a small rissoid-like gastropod were collected with chemoautotrophic bivalves. Subsequent morphological and molecular investigations revealed it to be a novel species of Desbruyeresia (Abyssochrysoidea: Provannidae), described herein as Desbruyeresia chamorrensis n. sp. Although all known specimens had a heavily corroded apex, so the protoconch could not be observed, its radular characteristics are very similar to those of other Desbruyeresia species. Phylogenetic reconstruction using the cytochrome c oxidase subunit I (COI) gene also supports its placement within Desbruyeresia. The new species is distinguished from all other described congeners by having more numerous (17–20) axial ribs on the teleoconch, and a broad shell for the genus (shell width to height ratio 0.6–0.65). Living Desbruyeresia were previously only known from hydrothermal vents and this is the first species known to inhabit seeps or serpentinite-hosted chemosynthetic habitats.

http://zoobank.org/urn:lsid:zoobank.org:act:3BDA021E-45ED-439A-9D5D-402BBB29293E

KEYWORDS:

• Caenogastropoda
• chemosynthetic ecosystems
• Mollusca
• new species
• South Chamorro
• serpentinisation

Acknowledgements

The authors are very grateful to the Captain and crews of the JAMSTEC R/V Natsushima as well as the ROV Hyper-Dolphin team on-board the expedition NT12-23 for their hard work and great support of scientific activity during the cruise. The United States Department of State and the Embassy of Japan in the USA are thanked for their help in acquiring the permission to work and sample on the South Chamorro Seamount, which is located within the American Exclusive Economic Zone. Finally, Dr. Winston Ponder and an anonymous reviewer are thanked for their constructive comments and help in improving an earlier version of this manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The genetic work was funded by a Japan Society for the Promotion of Science KAKENHI (grant no. 15K18602) awarded to Hiromi Kayama Watanabe.