Overview
- An international team reports in Science on Thursday that roughly 700 fossils from the Jiangchuan Biota in Yunnan place complex animals in the late Ediacaran, tens of millions of years before the Cambrian record.
- The cache includes abundant bilaterians and the oldest known deuterostome relatives, with forms such as stalked U‑shaped ambulacrarians and a tethered “bugle worm” showing specialized ways to feed and live.
- The fossils are preserved as carbonaceous films, a mode that captured guts and parts used for feeding and movement, which are details rarely seen at other Ediacaran sites that mostly leave simple impressions.
- The evidence narrows the long‑standing gap between molecular clocks and rocks by aligning genetic timelines with fossils, though a few experts caution that some identifications still need fuller testing.
- The Oxford–Yunnan team gathered the specimens during 2022–2024 and is now naming species and running phylogenetic analyses, and they plan to search for similar deposits that could reveal more of this transition.