Killer instinct drove evolution of mammals’ predatory ancestors

Mammalian progenitors ruled the earth for about 60 million years, long before the first dinosaurs arose. They diversified as top predators on Earth between 315-251 million years ago.

The researchers studied the jaw anatomy and body size of the carnivorous Synapsids, using these traits to reconstruct the possible feeding habits of these ancient predators and chart their ecological evolution over time. They found a major change in synapsid jaw function around 270 million years ago associated with a major change in hunting behavior that has important implications for the evolution of our earliest ancestors.

As herbivores grew larger and faster, carnivores adapted to become larger and better predators to survive.

“It was previously supported by famous cell-like synapsid hunters. DimetrodonLead author Dr Suresh Singh, based at the School of Earth Sciences in Bristol, explained, “It had long enough jaws with lots of teeth to ensure that once it had trapped its prey, it Don’t be saved. Short jaws with high muscle efficiency and fewer teeth concentrated in the front of the jaw — these jaws were adapted for deep, powerful bites.

“The change suggests that later synapsid carnivores placed more emphasis on injuring their prey more and killing them more quickly. These later synapsids were the first sabertoothed carnivores! This change highlights that that predators were facing new selective pressures from their prey.”

This finding provides important context for an important step in synapsid evolution. “The reorganization of synapsid jaws during this time is known to be a major step toward mammalian evolution,” added Dr. Armin Elsler, a co-author of the study. “These changes not only made the jaw more efficient; they also marked the earliest redevelopment of the jaw that created the complex ear found in mammals. What made this first step? Our The study suggests that this was partly due to environmental stressors. From their hunting.”

Co-author Dr Tom Stubbs said: “The timing of the change in jaw function is consistent with the evolution of new larger, faster herbivores that would have posed a greater challenge to predators.

“The risks of being injured or killed by carnivores increased, so some synapsid carnivores became larger, better killers to overcome these risks.”

This change reflects a new dynamic in predator-prey interactions that suggests life on Earth was moving more quickly.

“The Late Palaeozoic was when animals first started living on land, eating and fully reproducing,” said Professor Mike Benton, co-supervisor of the study.

“They became fully terrestrial, colonizing new habitats and exploiting new resources further inland from the aquatic environment they had previously relied on.

“Our results show how the selective pressures on these early land animals changed as they became better adapted to life on land – catching up to other animals that could move faster and grow to larger sizes. Yes, it’s much harder than catching a small, slippery fish or amphibian.”

Professor Emily Rayfield also co-supervised the study. He added: “Prey-prey interactions are a major driver of animal behavior today so it’s great to see this influence through millions of years of physiological evolution, and find that they are some of the biggest leaps in our own evolutionary history. are potentially responsible for planting.

“This highlights how paleontologists can use the relationship between form and function to learn how different prehistoric animals might have lived, which tells us a lot about the evolution of life on Earth.” can.”

The researchers also found that synapsid carnivore morphological diversity increased after the change, with the addition of new functional groups adapted to either faster bite speeds or even more powerful bites—about 265–251 million years ago By comparing the size of these new carnivore species within different communities over time, they found that these communities began to closely resemble modern carnivorous mammals.