CHANGSHA, November 8, 2026: More than 160 scientists from China, the United States, Canada, Russia and other countries have completed a joint investigation of ancient fossils in central China’s Hunan Province, uncovering new evidence about how marine life survived and recovered from a major extinction more than 500 million years ago.
According to the Chinese Academy of Sciences (CAS), the international researchers conducted field investigations and academic discussions at the Huayuan biota fossil site in Xiangxi Tujia and Miao Autonomous Prefecture.
The visit marked the first international field investigation of the site since findings about its fossils were published in the scientific journal Nature in January 2026.
The researchers concluded their work on Friday, identifying the site as an important source of evidence about the Cambrian explosion, a period when most major animal groups first appeared, and the subsequent Sinsk mass extinction.
Fossils fill major gap in Earth’s evolutionary history
Scientists believe the Huayuan biota provides an unusually detailed record of marine organisms that lived shortly after the Sinsk extinction.
The fossil collection fills a significant gap in the global record of soft-bodied animals from Cambrian Stage 4, a period between the better-known Chengjiang fossil assemblage in China and the Burgess Shale in Canada.
The Cambrian explosion, which occurred more than 500 million years ago, marked a major diversification of animal life.
However, the subsequent Sinsk mass extinction eliminated numerous early marine organisms, leaving scientists with limited evidence about which species survived and how ecosystems recovered.
Researchers say the Huayuan discoveries are helping address those questions.
Scientists discover more than 50,000 fossils
The research was led by Zhu Maoyan, an academician of the Chinese Academy of Sciences and researcher at the Nanjing Institute of Geology and Palaeontology.
His team conducted five years of systematic excavations at the Renkupo section in Mozi Village, Huayuan County.
The excavations yielded more than 50,000 fossil specimens representing 153 animal species, nearly 60 percent of which were previously unknown.
Scientists believe the exceptional preservation resulted from the area’s ancient deep-marine environment, which allowed delicate anatomical structures to survive in the geological record.
Zhu said earlier research, largely based on shallow-water fossils, had suggested that marine biodiversity declined sharply following the Sinsk extinction.
The newly discovered fossils challenge that interpretation by showing that diverse marine communities continued to exist in deeper waters.
He explained that deep-water environments may have provided natural refuges, protecting certain organisms from the worst effects of the extinction and allowing their evolutionary lineages to survive.
International researchers examine ancient marine ecosystems
John Paterson, a professor at Australia’s University of New England, described the Huayuan fossil site as exceptional because of the abundance and diversity of specimens.
He said the site contained numerous previously unknown organisms and offered substantial opportunities for further scientific investigation.
Jean-Bernard Caron, a researcher at Canada’s Royal Ontario Museum, highlighted similarities between fossils discovered in Hunan and those found in the Burgess Shale.
He suggested that some early marine organisms may have dispersed between distant regions through ocean currents carrying their larvae over long geological periods.
Douglas Erwin, an external professor at the Santa Fe Institute in the United States, said the fossils preserved remarkably fine internal anatomical details.
He noted that the presence of diverse organisms in deep-water deposits following the Sinsk extinction supported the possibility that deep-sea communities experienced higher survival rates than shallow-water populations.
Further research planned on mass extinction
Zhu said scientific investigation of the Huayuan biota remained at an early stage, with many unidentified fossil groups awaiting detailed study.
Researchers plan to combine palaeontology, geology and other scientific disciplines to investigate the scale of the Sinsk extinction and the environmental conditions that allowed marine organisms to survive.
Future studies will also examine how deep-water refuges developed and how ancient marine ecosystems changed following the extinction.
Scientists believe the discoveries could significantly improve understanding of the resilience of early animal life and the processes that shaped biodiversity on Earth.