Bathymodiolus thermophilus is a species of large, deepwater mussel, a marine bivalve mollusk belonging to the family Mytilidae. The species was discovered at abyssal depths when submersible vehicles began exploring the deep ocean. It occurs on the sea bed, frequently in large numbers, close to hydrothermal vents where hot, sulphur-rich water wells up through the floor of the Pacific Ocean.
This is a very large mussel with a dark brown periostracum, growing to a length of about 8 inches. It’s attached to rocks on the seabed by byssus threads but has the ability to detach itself and move to a different location. It’s sometimes very abundant, having been recorded at densities of up to 300 individuals per square meter.
It is found clustered around deep sea thermal vents on the East Pacific Rise and in the nearby Galapagos Rift at depths around a mile and a half.
Image Caption: Bathymodiolus thermophilus. Credit: Sabine Gollner, Barbara Riemer, Pedro Martínez Arbizu, Nadine Le Bris & Monika Bright/Wikipedia (CC BY 2.5)