Despite the close geographical distance between Bathymodiolus heckerae, B. childressi, and B. brooksi in the Gulf of Mexico, the symbionts in B. heckerae are much more closely related to the symbionts in a species of mussel off the western coast of Africa. Scientists are still trying to understand how and why these symbionts on opposite sides of the Atlantic are so closely related. Map adapted from a Sebastien Duperron image.
