Dinosaurs already adapted to polar climates may have been able to survive cold winters during end-Triassic extinction event, when most other animals died out
July 1, 2022
Some dinosaurs may have evolved traits that allowed them to endure cold winters in later stages Triassic and the Early Jurassic. It could explain how they came to dominate Earth for the next 135 million years.
Analysis of Rock and Sediments in Junggar Basin, Northwest China dinosaur footprints It has been discovered before, adding to a growing body of evidence that dinosaurs inhabited not only luscious green tropical landscapes, but also cold, icy forests.
Paul Olson Colleagues at Columbia University in New York and his colleagues found signs of frequent ice formation in the region. prehistoric reptile. The sediment contains unusually large grains that are typical of lakes that freeze over each year.
Dinosaur fossils found near polesbut models suggest that temperatures there dropped below freezing between 237 million and 174.1 million years ago, so no one knows whether these reptiles actually lived in cold environments.
Olson’s team’s findings could explain how dinosaurs continued to dominate Earth after nearly all large land and sea life in the tropics was wiped out.
Fossil dating shows Most mid-to-large continental reptiles disappeared suddenly at the end of the Triassic, when temperatures plummeted and a decade-long volcanic eruption filled the air with sulphur. But Olson said that after this extinction event, medium-to-large dinosaurs appeared quickly almost everywhere, and the adaptation of polar dinosaurs to cold may explain why.
When temperatures plummeted at the end of the Triassic, these dinosaurs were ready for it, feeding on polar vegetation and surviving the cold with feathers used as insulation, Olson said. These dinosaurs then expanded across the world throughout the Jurassic period, replacing large, non-insulated reptiles that had become extinct.
The latest evidence suggests that our concept of dinosaurs needs to be rethought, Olson said. “Our paper shows that our view of the dinosaur world is basically wrong,” he said. “Polar dinosaurs were not on the fringes. They were typical. And, in fact, dinosaurs were basically cold-adapted animals.”
Journal references: scientific progress, DOI: 10.1126/sciadv.abo6342
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