"CT scanning showed us that the similarity of Triopticus with the much later dome-headed pachycephalosaur dinosaurs was more than skin deep, extending to the structure of the bone and even the brain." co-author Lawrence Witmer of Ohio University's Heritage College of Osteopathic Medicine said.
It was not a coincidence that the reptile and dinosaurs resembled each other.
"After the enormous mass extinction 250 million years ago, reptiles exploded onto the scene and almost immediately diversified into many different sizes and shapes," co-author Sterling Nesbitt of Virginia Tech said. "These early body shapes were later mimicked by dinosaurs."
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Dinosaurs did not consciously do this, of course, but their ancestors and environment must have prompted the evolved similarities.
Many of the other Triassic reptiles originally buried with Triopticus at Otis Chalk display features that are easily recognized in later dinosaurs as well. These include the long snouts of Spinosaurus, the toothless beaks of ornithomimids (aka ostrich dinosaurs), and the armor plates of ankylosaurs.
"The Otis Chalk fauna is an amazing single snapshot of geologic time where you have this extraordinary range of animal body plans all present at the same time living together," Stocker said. "Among the animals preserved in the Otis Chalk fauna, Triopticus exemplifies this phenomenon of body-shape convergence because its skull shape was repeated by very distantly-related dome-headed dinosaurs more than 100 million years later."
Other studies over the past several years indicate that dinosaurs, like these distant cousins from the Triassic Period, were all reptiles. Reptiles rapidly evolved in terms of numbers of species soon after the greatest mass extinction of all time on Earth, at the end of the Permian Period.
You can manipulate 3D models of Three Eyes' skull at two different sites: one showing the partial skull alone and another showing the likely size and shape of the reptile's brain.
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