Bathymodiolus Kenk & B. R. Wilson 1985

The genus Bathymodiolus was first described in 1985 (Kenk and Wilson 1985). By 2010, according to Miyazaki et al. (2010), 22 Bathymodiolus species had been described (although the validity of several of these species has been questioned and a number of additional not yet formally described apparent species have been discovered, with others likely awaiting discovery). These mussels are among the dominant macroorganisms in chemosynthesis-based communities around hydrothermal vents and cold-water seeps in the deep sea. In the darkness of these ecosysystems, far from any light to support photosynthesis, Bathymodiolus mussels depend on symbiotic chemosynthetic, carbon-fixing bacteria harbored in their gill tissue; these bacteria oxidize sulphur or methane to generate the large amounts of energy required to fix inorganic carbon, which can then be used by the mussel host (reviewed in Duperron et al. 2009). Of the 22 Bathymodiolus listed in Miyazaki et al. (2010), 14 are Pacific species, 7 are Atlantic species, and one is known from the Indian Ocean. Related species also placed in the subfamily Bathymodiolinae include two Gigantidas species from the West Pacific and one Tamu species from the Atlantic. The group most closely related to the Bathymodiolinae appears to be the Modiolinae, members of which are found on sunken wood and whale carcasses. Recent molecular phylogenetic analyses have indicated that neither the genus Bathymodiolus nor, according to some analyses, the subfamily Bathymodiolinae are monophyletic, suggesting that the systematics and taxonomy of this group requires major revision. (Lorion et al. 2010 and references therein; Miyazaki et al. 2010 and references therein)

Bathymodiolus is a genus of deep-sea mussels, marine bivalve molluscs in the family Mytilidae. Many of them contain intracellular chemoautotrophic bacterial symbionts.