Fig. 1

Bathymodiolus sample localities along the East Pacific Rise (EPR), Galápagos Rift (GAR), and Pacific-Antarctic Ridge (PAR). Numbers in parenthesis indicate tectonic spreading rates in mm/year. Lines perpendicular to ridge axes indicate fracture zones. Inset illustrates a B. thermophilus bed at 9°N latitude (Photo credit: Stephen Low Productions, Courtesy of R. A. Lutz, Rutgers University)