The mighty dinosaur has fascinated people ever since the extinct creatures were first discovered. Working from bones and fossils, scientists now have a pretty good idea of what they likely looked like. But new information is being added to the mix, including the recent discovery that almost all dinosaurs likely had feathers.
Besides dinosaurs themselves, scientists have also been attempting to learn more about some of the relatives that existed before dinosaurs. Most paleontologists believed that dinosaurs' earliest ancestors likely resembled smaller versions of dinosaurs that would walk on two legs. But a recent discover uncovered an ancestor that looks much different than expected.
According to a new paper published in Nature, fossils from four different individual members of this species were discovered in southern Tanzania. From those fossils, they were able to piece together about half the skeleton. And from that, they could get a good clue of what the ancestor looked like.
After seeing how the bones fit together, they figured out that the creature probably looked a little something like this. It's not quite the mini-dino they thought it would be. It's got some dinosaur-like features, but it doesn't resemble it as closely as the researchers had expected.
The creature is called Teleocrater rhadinus. It's a six-to-ten-foot lizard-like carnivore that more closely resembles a crocodile. And it walks on four legs, not two.
The researchers say the findings are a huge breakthrough in studying dinosaurs and their cousins. “Teleocrater has unexpectedly crocodile-like features that are causing us to completely reassess what we thought about the earliest stages of dinosaur evolution,” said Ken Angielczyk, one of the authors of the study. “Surprisingly, early dinosaur relatives were pretty profoundly not dinosaur-like.”
The Teleocrater existed 245 million years ago, in the Triassic Period. This means it was around millions of years before the first dinosaurs. Instead of calling it a direct ancestor of the dinosaur, the researchers believe the Teleocrater is more of a "cousin."
Dinosaurs are part of larger group called archosaurus. But before dinosaurs existed, the archosaurs were divided into two groups 250 million years ago. One group was for the crocodile-like animals that evolved into today's alligators and crocs.
The other group was for bird-like creatures. This included the animals that would later evolve into dinosaurs, birds, and pterosaurs. But the Teleocrater is actually part of the bird and dino branch, not the croc branch.
The crocodile features of Teleocrater gives the researchers strong clues into how the archosaurus split off into two groups in the first place. “We used to think that many of the distinctive features of bird-line archosaurs evolved very quickly after they diverged from the crocodile line,” said Angielczyk. “Teleocrater shows us that bird-line archosaurs initially inherited many crocodile-like features from the common ancestor of all archosaurs.”
Angielczyk said the discovery is making scientists use a word they normally try to avoid. “Scientists generally don't love the term 'missing link,'” he said. “But that's kind of what Teleocrater is: a missing link between dinosaurs and the common ancestor they share with crocodiles.”
The Teleocrater was actually first identified by a British paleontologist named Alan Charig in the 1950s. But since little was known about dinosaur evolution at the time, Charig didn't realize the animal was related to dinosaurs. But thanks to this new study, Charig's findings now make more sense.
The team of researchers plan on going back to Tanzania in May to find even more remains of the Teleocrater. Sterling Nesbitt, the lead author of the study, is looking forward to learning even more. “The discovery of such an important new species,” he said, “is a once-in-a-lifetime experience.”