U.S. and Chinese paleontologists have discovered the oldest big cat fossil ever found.

Excavated during a 2010 expedition in the Zanda Basin in southwestern Tibet, the fossils belong to a previously unknown species recently named Panthera blythea, reports BBC. The skull fragments found date back between 4.1 million and 5.95 million years ago. Using anatomical and DNA data, the team of researchers was able to determine that the skulls were those of an extinct species of big cat – specifically a species much like the modern snow leopard.

"This cat is a sister of living snow leopards -- it has a broad forehead and a short face. But it's a little smaller -- the size of clouded leopards," said the paper’s lead author, Dr. Jack Tseng of the University of Southern California. "This ties up a lot of questions we had on how these animals evolved and spread throughout the world. Biologists had hypothesized that big cats originated in Asia. But there was a division between the DNA data and the fossil record."

The fossil were found by a team that included Tseng and his wife Juan Liu. More than 100 bones were discovered in the Zanda Basin of southwestern Tibet, reports the Washington Post. This included the crushed pieces of a big cat skull that was mainly complete and described as close to the size of a grapefruit. In total the site included seven skull fragments of at least three individual cats plus the nearly complete skull – a shocking find for the team. "Usually we find antelopes and rhinos, but this site was special. We found multiple carnivores - badgers, weasels and foxes," Tseng told BBC News.

The oldest known cat fossils before these were only 3.6 million years old. Those consisted of tooth fragments uncovered in Tanzania in the 1970s. But the new fossils best their age, ranging between 4.1 and 5.95 million years old. The complete skull was determined to be close to 4.4 million years old. And according to Tseng, the newly found fossils offer the most compelling support that big cats evolved in Central Asia and not Africa. The team plans to return to Tibet next summer to search for more fossils. The findings are published in the journal Proceedings of the Royal Society B: Biological Sciences.