Early lineages of mammals, like this large Gobiconodon from Mongolia, outcompeted the ancestors of modern mammals in the time of dinosaurs. Credit: Art by Corbin Rainbolt
SciTechDaily has an article about mammals during the age of dinosaurs. A new study published in Current Biology looked at how mammals evolved before and after the extinction that took out the non-avian dinosaurs at the end of the Cretaceous. The study found that it wasn't the dinosaurs that out competed the mammals, it was other mammals... and maybe even ancestral mammals.
A new study led by researchers from the Oxford University Museum of Natural History, University of Oxford, and the University of Birmingham for Current Biology has used new methods to analyze the variability of mammal fossils, revealing extraordinary results: it was not dinosaurs, but possibly other mammals, that were the main competitors of modern mammals before and after the mass extinction of dinosaurs.
The study challenges old assumptions about why mammals only seemed to diversify, becoming larger and exploring new diets, locomotion, and ways of life, after the extinction of the non-bird dinosaurs. It points to a more complex story of competition between distinct mammal groups. The new research also highlights the importance of testing old and established ideas about evolution using the latest statistical tools.
“There were lots of exciting types of mammals in the time of dinosaurs that included gliding, swimming, and burrowing species, but none of these mammals belonged to modern groups, they all come from earlier branches in the mammal tree,” said Dr. Elsa Panciroli, a researcher from the Oxford University Museum of Natural History and a co-author of the study. “These other kinds of mammals mostly became extinct at the same time as the non-avian dinosaurs, at which point modern mammals start to become larger, explore new diets and ways of life. From our research it looks like before the extinction it was the earlier radiations of mammals that kept the modern mammals out of these exciting ecological roles by outcompeting them.”
