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Reptile fossils hint at wide diversity of dinosaur ancestors

  • This artist’s rendering provided by Gabriel Lio in April 2017 shows the Teleocrater rhadinus, a four-legged, meat-eating reptile and a close relative of dinosaurs. Researchers who found its fossils in Tanzania in 2015 describe it in a paper released Wednesday, April 12, 2017 by the journal “Nature.” Gabriel Lio/Museo Argentino de Ciencias Naturales, Buenos Aires via AP

  • An artist’s rendering shows the Teleocrater rhadinus, a four-legged, meat-eating reptile and a close relative of dinosaurs. Researchers who found fossils in Tanzania in 2015 describe it in a paper released Wednesday by the journal “Nature.” Gabriel Lio/Museo Argentino de Ciencias Naturales, Buenos Aires via AP

  • This artist's rendering shows a Teleocrater rhadinus, center, a four-legged, meat-eating reptile and a close relative of dinosaurs, eating a relative of mammals, Cynognathus. The large dicynodont Dolichuranus is seen in the background. Researchers who found Teleocrater fossils in Tanzania in 2015 describe it in a paper released Wednesday, April 12, 2017, by the journal “Nature.” (Mark Witton/Natural History Museum, London via AP)

  • This artist's rendering shows the skeleton of the Teleocrater rhadinus, a four-legged, meat-eating reptile and a close relative of dinosaurs. The scale indicator at right is 10 inches. Researchers who found Teleocrater fossils in Tanzania in 2015 describe it in a paper released Wednesday, April 12, 2017, by the journal “Nature.” Scott Hartman via AP



Associated Press
Wednesday, April 12, 2017

Fossils of a four-legged, meat-eating reptile are helping paint a more complicated picture of the ancestry of dinosaurs than scientists had understood.

The creature was not a direct ancestor, but was more like a cousin. It lived about 245 million years ago, roughly 10 million years before dinosaurs appeared. It’s the oldest known member of an evolutionary branch of animals that eventually led to dinosaurs and pterosaurs, living relatively soon after that branch split away from the ancestry of crocodiles.

Researchers who found fossils in Tanzania in 2015 describe the creature in a paper released Wednesday by the journal Nature. It’s called Teleocrater rhadinus.

It was 7 to 10 feet long, smaller than crocodiles. While almost all early dinosaurs apparently walked on two legs, Teleocrater shows that a four-legged style was still present at this point, said Sterling Nesbitt of Virginia Tech in Blacksburg, lead author of the paper.

It also had a crocodile-like ankle, rather than the more bird-like ankle later seen in dinosaurs, and a surprisingly long neck, he said. The paper’s analysis indicates such dinosaur relatives were more diverse than thought, he said.

Luis Chiappe of the Natural History Museum of Los Angeles County, who didn’t participate in the study, called the work important for understanding the origin of dinosaurs. “It tells you about a much more complex picture than what was previously imagined,” he wrote in an email.