Palaeontology: A species-rich ancient marine ecosystem from China (Nature)
29 January 2026
A diverse collection of soft bodied fossils discovered in a quarry in southern China, dating to around 512 million years ago, is described this week in Nature. The so-called Huayuan biota contains 153 animal species from 16 major groups, of which 59% are previously undiscovered species. These well-preserved fossils offer the most complete view yet of marine ecosystems in the aftermath of the early Cambrian Sinsk event, a mass extinction that brought the Cambrian explosion to a close.
Much of what we know about the Cambrian explosion, which started around 540 million years ago, comes from rare Burgess Shale type deposits that preserve soft tissues. The Sinsk event disrupted this explosion with extinction rates of around 41–49%, especially among shallow water, skeleton bearing animals. Few sites yield abundant and diverse samples from the period directly after the Sinsk extinction around 513.5 million years ago. Thus, little was known about how soft bodied communities responded to this event, particularly in deeper waters. Existing records from Chengjiang and Qingjiang in China predate the extinction, whereas the Burgess Shale captures only much later ecosystems.
Across four field seasons between 2021 and 2024, Fangchen Zhao, Maoyan Zhu and colleagues uncovered thousands of well-preserved specimens at a quarry in the Hunan province in southern China. The Huayuan biota includes arthropods, sponges, tunicates and other invertebrates, as well as complete radiodonts — the apex predators of the Cambrian — indicating a complex food web. Statistical comparisons with 45 global Cambrian biotas reveal strong faunal links between Huayuan and the later Burgess Shale, suggesting long-distance dispersal across oceans driven by factors including currents and sea level changes. The results also show that deep-water soft bodied environments were less affected by the Sinsk extinction than shallow waters, and these deeper environments may have acted as refuges or centres of evolutionary innovation.
This complete biota fills a gap between fossil records from before and after the first mass extinction of the early Cambrian. Its shared taxa with the Burgess Shale strengthen evidence for early connections between South China and North America and provide new insights into how global marine ecosystems reorganized during the early Cambrian.
- Article
- Published: 28 January 2026
Zeng, H., Liu, Q., Zhao, F. et al. A Cambrian soft-bodied biota after the first Phanerozoic mass extinction. Nature (2026). https://doi.org/10.1038/s41586-025-10030-0
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