The climate-driven mass extinction no one had seen

Two thirds of all mammals vanished from Africa and the Arabian Peninsula around 30 million years ago, when the climate on Earth changed from swampy to icy. But we are only finding out about this mass extinction now. Researchers examined hundreds of fossils from multiple sites in Africa, built evolutionary trees, and pinpointed each species' first and last known appearances. The climate shift 'was a real reset button.'

source https://www.sciencedaily.com/releases/2021/10/211007145826.htm