Dinosaurs Already Adapted To The Cold Extinction Study Finds

The study, published in the journal Science Advances on July 1, examines the circumstances surrounding the Triassic-Jurassic extinction event 202 million years ago, which killed off many large reptiles and led to the eventual takeover of the dinosaurs. During the extinction event, researchers say the cold killed many cold-blooded reptiles. By studying footprints and rock fragments in a remote Junggar Basin desert in northwest China, researchers say Triassic dinosaurs, a relatively small group inhabiting Earth’s polar regions, survived the “evolutionary strait and spread.” “Dinosaurs were there during the Triassic under the radar the whole time,” said Paul Olsen, a geologist at Columbia University’s Lamont-Doherty Earth Observatory and lead author of the study. “The key to their eventual dominance was very simple. They were fundamentally cold-adapted animals. When it was cold everywhere, they were ready and other animals were not.” Dinosaurs are thought to have first appeared around 231 million years ago during the Triassic period in temperate southern latitudes, researchers say. At that time, most of the earth was united as one giant continent known as Pangaea. Dinosaurs arrived in the north about 214 million years ago, and until the mass extinction, reptiles dominated the tropical and subtropical regions of the planet. While atmospheric concentrations of carbon dioxide were then at or above 2,000 parts per million, or five times today’s levels resulting in “intense” temperatures, the researchers say climate models suggest that higher latitudes experienced seasonal temperature declines and would receive minimal sunlight most of the year. . By the end of the Triassic period, researchers say massive volcanic eruptions that could last hundreds of years killed more than three-quarters of all land and sea life on the planet. The eruptions would also have caused atmospheric carbon dioxide levels to rise, creating deadly temperature spikes and making ocean waters too acidic for many forms of life. But researchers say the eruptions would also release sulfur aerosols, capable of deflecting sunlight and causing recurring “global volcanic winters” lasting a decade and possibly longer. Not only were Triassic dinosaurs able to survive under these conditions, the researchers say the evidence showed that many, if not all, non-avian dinosaurs also had primitive feathers that would have been used primarily as insulation. Many dinosaurs are also believed to have been warm-blooded and had a high metabolism. “There is a stereotype that dinosaurs always lived in lush tropical jungles, but this new research shows that the higher latitudes would have been frozen and even covered in ice during some parts of the year,” said Stephen Brusatte, professor of paleontology and development at the University of Edinburgh, he said. “Dinosaurs living at high latitudes happened to already have winter coats [while] many of their Triassic competitors became extinct.” As for the physical evidence supporting their study, the researchers examined fine-grained sandstone and siltstone formations left behind in the sediments of shallow ancient lake bottoms in the Junggar Basin, which formed 206 million years ago during the Late Triassic. At that time, the basin would have been above the Arctic Circle. The tracks show the dinosaurs were present along the coasts, while pebbles about 1.5cm wide, found far from any visible coastline, offered evidence of “ice-rafted debris”, they say. Ice debris forms when ice accumulates on a coastal landmass and absorbs chunks of underlying rock, the researchers say. The ice eventually peels off and moves away. As it melts, the rocks fall and mix with the sediment. Researchers say the pebbles were likely collected during the winter when the lake’s waters froze and floated away as the weather warmed. “This shows that these areas froze regularly and the dinosaurs did just fine,” said study co-author Dennis Kent, a geologist at Lamont-Doherty. Researchers say more work is needed to find fossils in former polar regions, such as the Junggar Basin.

title: “Dinosaurs Already Adapted To The Cold Extinction Study Finds " ShowToc: true date: “2022-11-21” author: “Vena Fata”

The study, published in the journal Science Advances on July 1, examines the circumstances surrounding the Triassic-Jurassic extinction event 202 million years ago, which killed off many large reptiles and led to the eventual takeover of the dinosaurs. During the extinction event, researchers say the cold killed many cold-blooded reptiles. By studying footprints and rock fragments in a remote Junggar Basin desert in northwest China, researchers say Triassic dinosaurs, a relatively small group inhabiting Earth’s polar regions, survived the “evolutionary strait and spread.” “Dinosaurs were there during the Triassic under the radar the whole time,” said Paul Olsen, a geologist at Columbia University’s Lamont-Doherty Earth Observatory and lead author of the study. “The key to their eventual dominance was very simple. They were fundamentally cold-adapted animals. When it was cold everywhere, they were ready and other animals were not.” Dinosaurs are thought to have first appeared around 231 million years ago during the Triassic period in temperate southern latitudes, researchers say. At that time, most of the earth was united as one giant continent known as Pangaea. Dinosaurs arrived in the north about 214 million years ago, and until the mass extinction, reptiles dominated the tropical and subtropical regions of the planet. While atmospheric concentrations of carbon dioxide were then at or above 2,000 parts per million, or five times today’s levels resulting in “intense” temperatures, the researchers say climate models suggest that higher latitudes experienced seasonal temperature declines and would receive minimal sunlight most of the year. . By the end of the Triassic period, researchers say massive volcanic eruptions that could last hundreds of years killed more than three-quarters of all land and sea life on the planet. The eruptions would also have caused atmospheric carbon dioxide levels to rise, creating deadly temperature spikes and making ocean waters too acidic for many forms of life. But researchers say the eruptions would also release sulfur aerosols, capable of deflecting sunlight and causing recurring “global volcanic winters” lasting a decade and possibly longer. Not only were Triassic dinosaurs able to survive under these conditions, the researchers say the evidence showed that many, if not all, non-avian dinosaurs also had primitive feathers that would have been used primarily as insulation. Many dinosaurs are also believed to have been warm-blooded and had a high metabolism. “There is a stereotype that dinosaurs always lived in lush tropical jungles, but this new research shows that the higher latitudes would have been frozen and even covered in ice during some parts of the year,” said Stephen Brusatte, professor of paleontology and development at the University of Edinburgh, he said. “Dinosaurs living at high latitudes happened to already have winter coats [while] many of their Triassic competitors became extinct.” As for the physical evidence supporting their study, the researchers examined fine-grained sandstone and siltstone formations left behind in the sediments of shallow ancient lake bottoms in the Junggar Basin, which formed 206 million years ago during the Late Triassic. At that time, the basin would have been above the Arctic Circle. The tracks show the dinosaurs were present along the coasts, while pebbles about 1.5cm wide, found far from any visible coastline, offered evidence of “ice-rafted debris”, they say. Ice debris forms when ice accumulates on a coastal landmass and absorbs chunks of underlying rock, the researchers say. The ice eventually peels off and moves away. As it melts, the rocks fall and mix with the sediment. Researchers say the pebbles were likely collected during the winter when the lake’s waters froze and floated away as the weather warmed. “This shows that these areas froze regularly and the dinosaurs did just fine,” said study co-author Dennis Kent, a geologist at Lamont-Doherty. Researchers say more work is needed to find fossils in former polar regions, such as the Junggar Basin.