A new species of chemosymbiotic clam (Bivalvia: Vesicomyidae) from the Nankai Trough and Mariana Forearc

Chemosymbiotic vesicomyid clams in the subfamily Pliocardiinae are a major component of deep-sea chemosynthetic ecosystems, yet their diversity remains incompletely documented. Here, we report a new species of pliocardiine clam collected from two cold seeps, the 2,526 m deep Oomine Ridge site in the Nankai Trough, Japan and the 2,915 m deep Summit Site of South Chamorro Seamount, Mariana Forearc. This ovate species (maximum shell length 34.4 mm) is included in the genus Waisiuconcha Beets, 1943.