The deep-sea mussel Bathymodiolus septemdierum is a species of deep-sea mussel in the family Mytilidae, commonly found in hydrothermal vents in the western Pacific Ocean. This species harbors intracellular chemoautotrophic bacterial symbionts in its gills, which enable it to thrive in extreme environments by oxidizing methane or hydrogen sulfide to produce organic compounds. Bathymodiolus septemdierum plays a vital role in deep-sea ecosystems by contributing to nutrient cycling and supporting diverse microbial and faunal communities.
