Chinese scientists who analysed 1,000 eggshells unearthed in central China have concluded that dinosaurs were already in decline before becoming extinct 66 million years ago. The team said the eggshells found across 150 metre-thick rock layers represented only three species of dinosaur eggs found across habitats from the final two million years of the Cretaceous period, showing a clear drop...
Chinese scientists who analysed 1,000 eggshells unearthed in central China have concluded that dinosaurs were already in decline before becoming extinct 66 million years ago.
Study lead author Wang Qiang, an associate researcher at the Institute of Vertebrate Palaeontology and Palaeoanthropology of the Chinese Academy of Sciences, said dinosaurs eventually lost the ability to adapt to, and recover from, sudden changes in the environment. "The end-Cretaceous catastrophic events, such as the Deccan Traps and bolide impact, probably acted on an already vulnerable ecosystem and led to non-avian dinosaur extinction," they wrote, referring to the eruptions in India that caused worldwide temperature swings and the asteroid that sparked a heatwave and soot in the air that reduced the amount of light reaching the Earth.
But from the late Maastrichtian, the last division, only three families – the birdlike Oviraptoridae, duck-billed Hadrosauridae and Tyrannosauridae – and a few specimens of sauropods with long necks and tails were seen. "In particular, our data point to a low level of dinosaur diversity in the Shanyang Basin sustained for at least two million years prior to the end-Cretaceous mass extinction."