Scientists discover fossil of dinosaur ancestors with crocodile-like legs

In a major revelation, scientists have unearthed fossilised remains of more than 245-million-years old giant dinosaurs in southern Tanzania indicating that rather than walking on two legs, they walked on four crocodilian-like legs.

Most scientists used to assume that the earliest dinosaur relatives would resemble miniature dinosaurs, about the size of chickens, and walk on two legs, but the discovery of Teleocrater rhadinus, however, has forced them to reassess their ideas.

Based on a fossil unearthed in southern Tanzania, it has now been found out that these early relatives were carnivorous animals that measured approximately 7-10 feet long, with long necks and tails. Rather than walking on two legs, they walked on four crocodilian-like legs.

The finding, published in journal Nature, fills a gap in the fossil record.

The intact ankle bones and other parts of the skeleton helped scientists determine that the species is one of the oldest members of the archosaur tree and had a crocodilian look.

"The research sheds light on the distribution and diversity of the ancestors of crocodiles, birds and dinosaurs," said study author Judy Skog.

"It indicates that dinosaur origins should be re-examined now that we know more about the complex history and traits of these early ancestors," Skog added.

T. rhadinus predated dinosaurs, living more than 245 million years ago during the Triassic Period.

It shows up in the fossil record right after a large group of reptiles known as archosaurs split into a bird branch (leading to dinosaurs and eventually birds) and a crocodile branch (leading to alligators and crocodiles). T. rhadinus and its kin are the earliest known members of the bird branch of the archosaurs.

"The discovery of such an important new species is once-in-a-lifetime experience," said lead author Sterling Nesbitt at Virginia Tech.

"It's so exciting to solve puzzles like Teleocrater, where we can finally tease apart tricky mixed assemblages of fossils and shed light on broader anatomical and biogeographic trends in an iconic group of animals," said Michelle Stocker, a paleobiologist at Virginia Tech and co-author of the paper.