Sep 22, 2016

Wanna-Be Dino? Prehistoric Reptile Looked Like a Dinosaur

The preserved remains of Triopticus (left) show the evolution of a thickened domed skull in the Triassic Period, 150 million years before the evolution of the famous dome-headed pachycephalosaur dinosaurs, such as Stegoceras (right). The background image shows the field site in Texas where WPA crews in 1940 found the curious fossils of Triopticus.
A reptile that lived before the Dinosaur Age resembled a dino, suggesting that iconic dinosaur body shapes were present long before the dinosaurs themselves actually emerged.

The newly identified reptile, described in the journal Current Biology, resembled pachycephalosaur dinosaurs that lived more than 100 million years later. Other extinct animals found with the reptile looked like later dinos too.

The reptile has been named Triopticus primus, meaning the "First of Three Eyes" because the natural pit at the top of its skull lends the appearance of an extra eye.

"Triopticus is an extraordinary example of evolutionary convergence between the relatives of dinosaurs and crocodylians and later dinosaurs that is much more common than anyone ever expected," co-author and project leader Michelle Stocker, a Virgnia Tech College of Science researcher, said in a press release. "What we thought were unique body shapes in many dinosaurs actually evolved millions of years before in the Triassic Period, about 225 million years ago."

Convergence refers to when distantly related animals evolve to look very similar to each other. A classic example of this is a bird wing and a bat wing. Both animals use their wings for flight, yet the inner details of their wings are different and evolved independently.

Three Eyes dates to about 230 million years ago, according to the researchers. The reptile's partial skull was originally collected at a site called Otis Chalk near Big Spring, Texas, by the Works Progress Administration in 1940.

President Franklin Roosevelt had initiated a monumental effort to put Americans back to work at end the Great Depression. With so much digging going on, numerous fossils were unearthed. In fact, so many fossils were found during such a short time span that several of them were just put into storage uncleaned.

Such was the case for Three Eyes, whose skull was eventually sent to the Texas Vertebrate Paleontology Collections in 2010. It is there that Stocker and her team rediscovered and analyzed the specimen.

They determined that the reptile had an extremely thickened skull roof, just like the very distantly related pachycephalosaur dinosaurs that lived more than 100 million years after the lifetime of Three Eyes.

"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."

Read more at Discovery News

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