Heftier than modern-day gray wolves and capable of cracking the bones of their prey, dire wolves were among the Pleistocene’s most-feared hunters. It’s long been believed that these top predators lived only in the Americas, but researchers have now unearthed the first fossil evidence that dire wolves also inhabited Asia, which they reported this month in Quaternary International.

In 2017, a sand-mining operation on the Songhua River in northeastern China dredged up an unusual fossil. The specimen, roughly four inches long, was a fragment of a lower jawbone with an intact molar, and it clearly belonged to a canine species. But the fossil was distinctly different from the gray wolf jawbones that had been previously unearthed from the river’s depths.

For starters, the molar topped an inch and a quarter in length. “It’s much bigger than the gray wolf’s,” said Xijun Ni, a paleoanthropologist at the Chinese Academy of Sciences.

Dr. Ni and his team brought the jawbone to their laboratory in Beijing. There, they used computed tomography scanning to build a three-dimensional model of the fossil. The researchers compared more than a dozen of its anatomical features with measurements from extinct and living canines. The closest match, they found, was the extinct Canis dirus, the dire wolf.