A new joint study by researchers suggests that the arctic fox originated in China's Qinghai-Tibet Plateau some five million years ago, strengthening the plateau's role as the "third pole" in evolution.

An international team led by scientists, including paleontologist Wang Xiaoming and Li Qiang, uncovered fossils of a new species of Tibetan fox from 3 to 5 million years ago in the Zanda Basin in the plateau's southwestern region, according to a paper released Wednesday in the journal Proceedings of the Royal Society B: Biological Sciences.

The paper, with Wang as the lead author, describes the fossil fox as the likely ancestor of the arctic fox due to their similar features, including strong and sharp teeth fit for hypercarnivorous behaviors.

Wang, born in China and currently living in the United States, is a guest researcher with the Institute of Vertebrate Paleontology and Paleoanthropology under the Chinese Academy of Sciences. The institute's Li Qiang is among the paper's co-authors.

The paper, the result of 15 years of field work and research, notes that the Qinghai-Tibet plateau, in southwest China, boasts the largest tundra and glacier area on Earth outside the Arctic and Antarctic regions, and mammals living there have cold-resistant thick coats similar to those in the polar regions.

The finding challenges the popular notion that the origin of present-day mammals within the Arctic Circle is in areas north of the Tropic of Cancer in the northern hemisphere.

Previously, fossils of megafauna, including the remains of the earliest known species of woolly rhino, one of the Ice Age's most iconic mammals, was uncovered in the basin. The latest finding further strengthened an alternative theory that the plateau was a "training ground" for mammals to adapt to cold before moving north.