Missing Middle? Fossils of Crocodile-like Ancestors to Dinosaurs Found

Phillip Butler
April 14, 2017

A report released by Nature shows that the teleocrater is believed to be the earliest-known dinosaur relative and was six feet long and had features like a crocodile.

How did the dinosaur become the dinosaur?

In any case, that ancient shared ancestor of both crocodiles and dinosaurs (and birds) may have looked more like the former than the latter.

The surprising thing is that the earliest ancestors of dinosaurs were not the least bit like the dinosaurs. An worldwide team of researchers have just published in Nature a description of Teleoctrater rhadinus, which represents the first step on the path from archosaurs toward dinosaurs and birds. "If we want to understand how the very distinctive dinosaur and bird body plan evolved into something that's very successful. teleocrater provides insight into the first step in that process". This makes it the oldest known cousin of the dinosaurs.

Some 251 million years ago, at the end of the Permian period, a mass extinction wiped out most of life on Earth. At the starting point of the Triassic Period, the archosaurs broke into two branches: the bird bunch and the crocodile crew. Its legs were shorter than a dinosaur's, but not as sprawling as those of a crocodile. Dinosaurs and pterosaurs all have a version of a hinged, birdlike ankle, rather than the crocodilelike ankle with ball-and-socket joint.

"The discovery of Teleocrater fundamentally changes our ideas about the earliest history of dinosaur relatives", said Nesbitt. And numerous fossils that do exist, collected perhaps decades to a century ago, languish unidentified in museum drawers.

The team, which includes researchers from the United States, England, Argentina, South Africa, Sweden and Russian Federation, identified several features, like a depression in its skull, that further showed the Teleocrater was an archosaur from the bird lineage.

Angielczyk and his colleagues said that while Teleocrater was being formally named for the first time in their paper, it was first identified by British paleontologist Alan Charig in the 1950s, using fossils collected in the 1930s.

Charig died in 1997, but scientists are finally recognising a odd dinosaur relative he named but never formally published 60 years ago.

It's kind of like the trait of walking upright, or bipedalism, in our own family tree.

The new fossils were unearthed in 2015, and the state of the remains helped scientists figure out where the Teleocrater came from. Dinosaurs were the largest animals to walk on land and they dominated the planet for 150 million years (humans, by contrast, have been around for just 200,000 years). But a newly indentified dino cousin may shake up the prehistoric family tree. This led to dinosaurs and eventually bird and crocodile branches, which eventually led to modern alligators and crocodiles. Okay, that's not really the case...phylogenetic analysis of Teleocrater and some other very early stem-avian fossils determined they could all fall into the aphanosaur gang.

Archosaurs are the common ancestors of birds and crocodiles.

Early dinosaur relatives like Teleocrater lived in present-day Russia, India, Brazil and, now we know, Tanzania.

Most paleontologists expected the earliest dinosaur relative to look more or less like a mini dinosaur - not exactly. Although dinosaur predators had two legs, Teleocrater instead was four-legged.

Other reports by Ligue1talk

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