Overview
- Researchers report more than 700 fossils from the Jiangchuan Biota in Yunnan, China, dated to 554–539 million years ago, in a peer-reviewed Science paper.
- The assemblage includes the oldest known relatives of deuterostomes and forms resembling ambulacrarians, the group that today includes starfish and acorn worms.
- Many specimens are bilaterian, worm-like animals with anchoring discs and complex feeding structures, along with rare fossils interpreted as early comb jellies.
- The fossils are preserved as thin carbonaceous films, a style typical of sites like the Burgess Shale, and the team argues this preservation bias helps explain why similar animals are scarce at other Ediacaran sites.
- The authors say the find shifts parts of the Cambrian diversification into the late Ediacaran and note that formal descriptions and evolutionary placements will take years of further work.