Thiosocius teredinicola strain:2141T.STBD.0c.01a Genome sequencing and assembly. Thiosocius teredinicola strain:2141T.STBD.0c.01a

Certain marine invertebrates harbor chemosynthetic bacterial symbionts, giving them the remarkable ability to consume inorganic chemicals such as hydrogen sulfide (H2S) rather than organic matter as food. These chemosynthetic animals are found near geochemical (e.g. hydrothermal vents) or biological (e.g. decaying wood or large animal carcasses) sources of H2S on the sea floor. Although many such symbioses have been discovered, little is known about how or where they originated. Here we demonstrate a new chemosynthetic symbiosis in the giant teredinid bivalve (shipworm) Kuphus polythalamia and show that this symbiosis arose in a wood-eating ancestor via the displacement of ancestral cellulolytic symbionts by sulfur-oxidizing invaders. Here wood served as an evolutionary stepping stone for a dramatic transition from heterotrophy to chemoautotrophy.