LHASA, Dec. 23 -- A group of fossils discovered on the Qinghai-Tibet Plateau have been confirmed as pliocene-era bone-crushing hyenas, which date back some four million years, a Chinese archaeologist said Wednesday.

The fossilized teeth and lower jaws were discovered in 2012 at an altitude of 4,195 meters in the Zanda basin, southwest of Tibet Autonomous Region in southwest China.

After years of research by Chinese and U.S. scientists, both sides agreed that the fossils date from the Pliocene Epoch (five to three million years ago), making this discovery the first on Qinghai-Tibet Plateau, according to the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) under the Chinese Academy of Sciences.

"Pliocene hyenas were dog-like predators. Their bone-crushing teeth were perfect for tearing up prey," said Li Qiang, an IVPP researcher and member of the research team.

Apart from the hyenas, canids and Tibetan antelopes also lived on the Zanda basin during the early Pliocene.

Research on the fossils has proved that hyenas lived on the plateau, and as far as west Europe, during the early Pliocene.

"Pliocene hyenas belong to the Hyaenidae family, which has six species and first appeared during the late Miocene Epoch [11.6 to 5.3 million years ago]," said Li. "They are likely to have originated from north China but disappeared 2.2 million years ago. No fossils have been found after then."

Most of hyena species, distributed mainly across Asia, Europe and Africa, became extinct 700,000 years ago. The African spotted hyena is the only hyena species to survive today.

The research findings were published in the online edition of "Historical Biology," an international paleontology journal.