An ancient Oregon fossil that was misidentified for about 50 years was recently revealed to be a jaw bone of a rare prehistoric bone-crushing hoofed mammal.

It is the first fossil of that mammal to be found in the Northwest.

Paleontologists thought the 40-million-year-old fossil from the John Day Fossil Beds came from a Hemipsalodon, a polar bear-like creature. But recent research revealed it is from a Harpagolestes, a hoofed mammal that looked like a cross between a pig and a hyena.

“Imagine a pig that specializes in eating only bones,” said Nicholas Famoso, chief of paleontology at John Day Fossil Beds National Monument.

The fossil was reexamined about two years ago, when a paleontology student at the University of Oregon was tasked with examining the fossil as part of a routine class research assignment.

“We were coming up with ideas for a project,” Famoso said. “We thought it shouldn’t be too hard for her to find out what it is. We knew what it was labeled.”

But the student, Selina Robson, was convinced the fossil was misidentified and set out to prove it with the help of Famoso and advisers in the university’s earth sciences department.

Robson’s results got everyone’s attention.

“We weren’t expecting her to say: ‘This isn’t what you think it is,’” Famoso said.

In June, their work was published in the peer-reviewed science journal, Palaeontologia Electronica, proving the correct identity of the rare fossil and the fact that it is the first of its kind found in the region.

“For scientists, that is actually a really big deal,” Famoso said.

The jaw bone fossil was originally discovered in the old Wheeler County Hancock Quarry, which is within the Clarno Unit of the John Day Fossil Beds.

It sat misidentified for five decades in the University of Oregon Museum of Natural and Cultural History.

The fossil is being safely kept in the museum’s collection. The university and national park are discussing putting it on display at the museum or making a replica that can be displayed at the national park.

Famoso said he hopes the fossil is the first step in learning more about the prehistoric hoofed mammal that has no modern descendants. Fossils from the mammal have been found in Southern California and across the Rocky Mountains. Now, Famoso can picture the mammal in the Northwest.

“They behaved like hyenas,” Famoso said. “They were running around Oregon being the first animals chewing on bones.”

After correctly identifying the mammal’s fossil, Famoso wants to reexamine other fossils in the university’s collection to see if any more have been misidentified.

“It definitely warrants reviewing some of the specimens we already have,” he said. “We need to double check.”

Properly identifying fossils at first glance can be difficult, Famoso said. Before new technology that can X-ray a fossil, paleontologists had a hard time examining a fossil without damaging it.

The team that identified the hoofed mammal fossil sent it through a CT scan at a hospital in Eugene.

The computer scan was able to show the shape of the teeth and jaw bone without having to cut into the fossil, Famoso said.

“When technology like CT scans come around, we can use that to solve a lot of those questions,” he said.

Patrick Gamman, superintendent at John Day Fossil Beds National Monument, said new discoveries like the hoofed mammal fossil are part of the park’s mission to study the prehistoric landscape of Eastern Oregon.

“We have 45 million years of really amazing fossils that are significant for the entire world,” he said.

The newly identified fossil will lead to more questions about what the mammal was doing in present day Oregon and how it fit into the prehistoric ecosystem, Gamman said.

“We keep piecing this together and we get more and more of the story,” he said.

— Reporter: 541-617-7820,