image: Maps showing the North China Craton’s position and the Yanliao region’s basins during the Middle Jurassic (ca. 175 Ma). The Beipiao and Xiahuayuan basins, key study areas, highlight the tectonic and sedimentary context of the Yanliao Biota.
Credit: ©Science China Press
The Yanliao Biota, a collection of well-preserved Middle Jurassic fossils from East Asia, includes early mammals capable of swimming and gliding, as well as dinosaurs that reveal the origins of birds. A new study by Chinese scientists, published in National Science Review, shows how a climate shift around 167 million years ago created diverse habitats, fueling evolutionary breakthroughs in the Yanliao region.
Conducted by Dr. Wenxing Hao from the Chinese Academy of Sciences, the team studied the Beipiao and Xiahuayuan basins. They analyzed sediments, pollen records, and carbon isotopes, identifying a climate shift around 167 to 165.5 million years ago. This period saw fewer coal deposits and a change from fern-heavy to pine-like vegetation, indicating less humid conditions. The study estimated a reduction in annual rainfall from over 1,000 mm to below 750 mm, based on modern comparisons, corroborated by climate models and evidence of decreased chemical weathering in the region’s rocks.
This climate shift, combined with tectonic activity, changed the region from wet river and lake systems to seasonal plains. These varied landscapes created new ecological niches, allowing species to evolve in isolation. For example, early mammals developed gliding and digging behaviors, while dinosaurs like Anchiornis evolved feathers, suggesting the origins of flight.
“This shift to sub-humid conditions created a patchwork of habitats,” said Dr. Wenxing Hao, lead author of the study. “It gave species room to adapt in unique ways, sparking the incredible diversity of the Yanliao Biota.”
The findings also shed light on modern challenges. “By studying how past climate changes shaped life, we can better understand how today’s ecosystems might respond to environmental shifts,” Dr. Hao added.
The research team, including experts from the Chinese Academy of Sciences, China University of Geosciences, Peking University, and Hefei University of Technology, analyzed sedimentary and pollen data alongside climate simulations. Their work reveals how environmental changes drove species diversification through ecological isolation, offering insights into Earth’s evolutionary history.
See the article:
Climate change enhanced habitat diversification for the Middle Jurassic Yanliao Biota in East Asia
https://doi.org/10.1093/nsr/nwaf194
Journal
National Science Review