Overview
- The Jiangchuan Biota, described Thursday in Science, includes more than 700 soft‑bodied fossils from Yunnan dated to about 546–539 million years ago in the late Ediacaran, the period just before the Cambrian.
- The fossils are preserved as thin carbon films that keep details like guts and parts used for feeding and moving, which lets researchers read body plans in soft tissues.
- The team reports early bilaterians with left‑right symmetry and the oldest known deuterostomes, including stalked animals with tentacles and a “bugle worm” with an inside‑out proboscis.
- The finds show animal diversification was already underway before the Cambrian explosion, pointing to earlier swimming, hunting, and seafloor churning that began to remake ocean ecosystems.
- Experts say the trove narrows the long dispute between DNA‑based timelines and rocks, though some paleontologists question whether all specimens are unmistakably complex animals.