Southern Africa solves riddle of dinosaurs' earliest relatives

13 April 2017 - 17:49 By Dave Chambers
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Teleocrater rhadinus, a carnivorous animal that lived in southern Tanzania more than 245 million years ago during the Triassic Period, before dinosaurs.
Teleocrater rhadinus, a carnivorous animal that lived in southern Tanzania more than 245 million years ago during the Triassic Period, before dinosaurs.
Image: Artwork: Mark Witton/Natural History Museum, London

A discovery in Southern Africa has filled a missing evolutionary link that eventually led to dinosaurs and birds.

A fossil dug up in southern Tanzania in 2015 will force a reassessment of dinosaur origins‚ the US National Science Foundation said on Thursday.

Teleocrater rhadinus were carnivores around three metres long‚ with long necks and tails. They walked on four crocodile-like legs‚ according to a study published in the journal Nature.

“The research sheds light on the distribution and diversity of the ancestors of crocodiles‚ birds‚ and dinosaurs‚” said Judy Skog‚ a programme director in the foundation's earth sciences division.

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

An artist's rendering of Teleocrater rhadinus. Picture: Gabriel Lio

T. rhadinus predated dinosaurs‚ living more than 245 million years ago during the Triassic Period. Its place in the fossil record comes immediately 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 a once-in-a-lifetime experience‚” said Sterling Nesbitt‚ a paleobiologist at Virginia Tech and lead author of the Nature paper.

Teleocrater rhadinus hunting an early close relative of mammals. Picture: Gabriel Lio

The late paleontologist Rex Parrington found T. rhadinus fossils in Tanzania in 1933. The late Alan Charig‚ then-curator of fossil reptiles‚ amphibians and birds at the Natural History Museum in London‚ was the first to study those original specimens in the 1950s.

Charig could not determine whether the creature was more closely related to crocodilians or to dinosaurs‚ largely because the specimens lacked ankles and other bones. The new specimens‚ found in 2015‚ clear up those questions. 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.

Nesbitt and his co-authors honoured Charig’s work by using the name he selected for the animal‚ Teleocrater rhadinus‚ which means “slender complete basin” and refers to the animal’s lean build and closed hip socket.

“The discovery of Teleocrater fundamentally changes our ideas about the earliest history of dinosaur relatives‚” said Nesbitt.

TMG Digital/TimesLIVE

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