New research from the University of Bristol provides evidence that many mammals were already shifting toward a more ground-based lifestyle leading up to the end-Cretaceous mass extinction that wiped out non-avian dinosaurs 66 million years ago.
Dryolestes, a Late Jurassic relative of Cretaceous therian mammals. Image credit: James Brown / Pamela Gill / University of Bristol.
Present-day mammals mostly live in diverse habitats dominated by flowering plants (angiosperms).
Unlike those provided by coniferous vegetation, woodland and forest habitats have a dense and complex understory as well as larger trees, providing high biodiversity and resources for terrestrial mammals of all sizes.
However, these flowering plant-dominated habitats are relatively new in Earth history, being mainly a feature of the Cenozoic Era (66 million years ago until today), but first developing towards the end of the Cretaceous.
“Mesozoic mammals were small, almost entirely under 5 kg in mass, with the largest no greater than around 10 kg,” said University of Bristol Professor Christine Janis and coll