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

• Published in: Molluscan research 2016-10, Vol.36 (4), p.277-284
• Main Authors: Chen, Chong, Ogura, Tomomi, Hirayama, Hisako, Watanabe, Hiromi Kayama, Miyazaki, Junichi, Okutani, Takashi
• Format: Article
• Language: English
• Subjects: Caenogastropoda; chemosynthetic ecosystems; Mollusca; new species; serpentinisation; South Chamorro
• ISSN: 1323-5818; 1448-6067
• DOI: 10.1080/13235818.2016.1172547

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