Scientists say they have unearthed fossils belonging to an elephant-sized reptile that lived alongside dinosaurs in Eastern Europe more than 200 million years ago.

The find, published in the journal Science on Thursday, means dinosaurs weren't the only giants that existed during the Triassic Period, as previously believed. 

Researchers discovered the fossilized bones of the four-legged creature, named Lisowicia bojani, at the village of Lisowice in southern Poland.

"Such an important new species is a once in a lifetime discovery," said Tomasz Sulej of the Polish Academy of Sciences, who worked on the study. 

The team of scientists from Poland and Sweden said Lisowicia had a body like a giant rhinoceros and was equipped with a turtle-like beak for munching plants.

They identified it as a previously unknown species of dicynodont — a herbivorous mammal-like reptile that could range in size from a small rat to an ox. Lisowicia, weighing 10 tons and stretching 4.5 meters (15 feet) in length, would have been about 40 percent larger than any previously identified dicynodont. 

"The discovery of Lisowicia changes our ideas about the latest history of dicynodonts," Sulej said. "It also raises far more questions about what really makes them and dinosaurs so large."

Read more: New giant bird-like dinosaur species discovered in smuggled fossil

Mammal cousin

Dicynodonts belonged to the same evolutionary branch as mammals, despite their reptile origins. They managed to survive the mass extinction known as The Great Dying around 250 million years ago that killed up to 90 percent of Earth's species. But they were thought to have died out before the late Triassic era (between about 240 million and 201 million years ago) when dinosaurs appeared.

But an analysis of Lisowicia bone specimens showed they actually survived until around 210-205 million years ago — around the time when dinosaurs had become the dominant land creature, growing to huge sizes while early mammals retreated.

Read more: Dinosaurs are extinct because asteroid hit the wrong spot

"The late Triassic Period wasn't just the time of the rise of dinosaurs, it was also the time when the last dicynodonts decided to compete with dinosaurs. Finally, dinosaurs won this evolutionary competition," said Sulej.

Christian Kammerer, a dicynodont specialist at the North Carolina Museum of Natural Sciences who wasn't involved in the study, called it "very intriguing and important."

"Large dicynodonts have been known before in both the Permian and the Triassic, but never at this scale," he said.

Read more: 'The dinosaurs were a little bit unlucky'

nm/cmk (AFP, AP, Reuters)

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