The evolutionary success of the first large predators on land was driven by their need to improve as killers, researchers at the University of Bristol and the Open University suggest.
The forerunners of mammals ruled the Earth for about 60 million years, long before the origin of the first dinosaurs. They diversified as the top predators on land between 315–251 million years ago.
Researchers studied the jaw anatomy and body size of carnivorous synapsids, using these traits to reconstruct the likely feeding habits of these ancient predators and chart their ecological evolution through time. They found a major shift in synapsid jaw function roughly 270 million years ago linked to a significant shift in predatory behavior that has important implications for the evolution of our earliest ancestors.
As herbivores grew larger and faster, carnivores adapted to become bigger and better predators to survive.
“Earlier synapsid predators such as the famous sail backed Dimetrodon, had fairly long jaws with lots of teeth to ensure that once they ensnared their prey, it wouldn’t escape,” explained lead author Dr Suresh Singh based in Bristol’s School of Earth Sciences. “However, we saw a shift in jaw function toward shorter jaws with greater muscle efficiency and fewer teeth that were concentrated at the front of the jaw - these were jaws adapted to deliver deep, powerful bites.