China fossil find shows how change of pace helped dinosaurs survive
- Scientists say discovery confirms ancestors of crocodiles evolved to walk instead of crawl before the end-Permian mass extinction
- The structure discovered gave the ruling reptiles the ability to adapt to global warming, and also to run, according to study
Some scientists have previously proposed that archosaurs – represented today by birds and crocodiles – became capable of walking with their limbs perpendicular to the ground, like mammals, to avoid the heat of the Earth’s surface during the following Triassic period.
But the latest study, published in December by peer-reviewed journal The Science of Nature, has pushed forward the timeline for archosaurs – “ruling reptiles” – which once included dinosaurs and pterosaurs.
Co-author Chen Jianye, a researcher at the Institute of Vertebrate Palaeontology and Palaeoanthropology, said the development of the necessary structure to walk upright had given archosaurs the ability to adapt to global warming.
“The evolution of walking ability was not prompted by climate change. But having such a structure made it easier for archosaurs to adapt to the warming conditions in the early Triassic,” he said.
Like today’s lizards, early reptiles crawled with their limbs almost flat and their bellies close to the ground, bending from side to side. But to run fast, like a velociraptor – a dinosaur which could reach 40km (25 miles) per hour – an animal needed to be upright. The erect posture developed by later archosaurs was “the key to running”, Chen said.