A bizarre new dinosaur lineage has been discovered in Chile, and though it is closely related to the famous carnivorous Tyrannosaurus rex, it curiously had an appetite for plants rather than meat.

Palaeontologists are referring to this vegetarian cousin as Chilesaurus diegosuarezi, or the "platypus" dinosaur, so named for its unusual mix of characteristics that resemble different dinosaur groups.

For example, Chilesaurus boasted a proportionally small skull, hands with two fingers like Tyrannosaurus rex, and feet more akin to primitive long-necked dinosaurs.

Several fossil remains of Chilesaurus were first discovered at the Toqui Formation in Aysén, south of Chilean Patagonia, in rocks deposited at the end of the Jurassic Period, approximately 145 million years ago. Due to its bizarre blend of features, scientists initially thought it was several species. However, since then more than a dozen Chilesaurus specimens have been excavated, proving that this dinosaur was just one species that sported a variety of unique anatomical traits.

It turns out Chilesaurus a group of dinosaurs called theropods, which includes the famous meat eaters Velociraptor, Carnotaurus and Tyrannosaurus, and from which modern birds evolved.

Until now, herbivorous dinosaurs were only known in close relatives of birds, but Chilesaurus shows that a meat-free diet was acquired much earlier than thought.

"Chilesaurus is the first complete dinosaur from the Jurassic Period found in Chile and represents one of the most complete and anatomically correct documented theropod dinosaurs from the southern hemisphere. Although plant-eating theropods have been recorded in North America and Asia, this is the first time a theropod with this characteristic has been found in a southern landmass," Dr. Fernando Novas, who led the research, said in a statement.

Its diet is only partially to explain for Chilesaurus' unique features. Its way of life, which was similar to other groups of dinosaurs, also played a role. As a result of these similar habits, different regions of the body of Chilesaurus evolved resembling those present in other, unrelated groups of dinosaurs - referred to as evolutionary convergence.

"Chilesaurus shows how much data is still completely unknown about the early diversification of major dinosaur groups. This study will force paleontologists to take more care in the future in the identification of fragmentary or isolated dinosaur bones," said researcher Martín Ezcurra, of the University of Birmingham.

The findings were published in the journal Nature.

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