Serrated Teeth Of First Land Predators Offer Fresh Clues About What Animals Were First To Walk The Earth
The Dimetrodon was the first land animal to hunt for its food, and now researchers have discovered that it was also the first land predator to use its teeth like a hacksaw. A University of Toronto Mississauga study used new technology to analyze the skull fossils of the nearly 300-million-year-old beast and discovered that Dimetrodon's teeth were serrated. The findings could offer new insights into an ancient ecosystem.
"Teeth tell us a lot more about the ecology of animals than just looking at the skeleton," said Robert Reisz, co-author of a study that appeared Friday in the journal Nature Communications. Dimetrodon was a dinosaur predator at the top of the food chain. Just 13 feet long, they would've been something like a modern crocodile with a sail on its back. They would've appeared far less ferocious than the theropod dinosaurs — including the Tyrannosaurus and Velociraptor. But this new research may change that perception.
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Reisz and his colleague, Kristin Brink, used advanced microscope techniques to explore Dimetrodon fossils. Using fossils dating to different time periods, they noticed that the creature's teeth morphed over 25 million years of its existence, though its skull structure in general never did. This suggested that Dimetrodon teeth adapted to a new, larger, and meatier diet over the years. And in fact, its serrated teeth first appeared about 40 million years before theropods developed the same quality.
"The steak knife configuration of these teeth and the architecture of the skull suggest Dimetrodon was able to grab and rip and dismember large prey," Reisz said in a statement. "This research is an important step in reconstructing the structure of ancient complex communities. ... We already know from fossil evidence which animals existed at that time but now with this type of research we are starting to piece together how the members of these communities interacted."
In other words, serrated teeth doesn't just tell us that these lizards had serrated teeth. It tells us that they had to adapt to a changing world around them, full of bigger prey. And that's helpful to paleontologists; very little is known about the first millions of years when animals came out of the seas and onto the land. Whatever their adaptations, the Dimetrodon died out around 272 million years ago. About 20 million years later, most of the rest of life on Earth would join them during the Permian-Triassic extinction event.
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