Newly Discovered Beaver-Like Mammal Species Survived Dinosaur Extinction, Researchers Say

Not all living animals faced the same fate when the dinosaur-killing asteroid impacted with the Earth 66 million years ago. Kimbetopsalis simmonsae, a furry prehistoric beaver-like animal, survived and became top dog following the dinosaurs' demise, according to a new study.  

Kimbetopsalis fossils were recently discovered among rock formations of New Mexico's badlands. The animal evolved during the Jurassic period and laid low while the dinosaurs ruled the land – at least until the asteroid hit.

"All this ecological space became available and the mammals went a bit nuts," Sarah Shelley, a paleontologist at the University of Edinburgh and a co-author on the paper, said in a statement.

Over the course of the next 500,000 years, Kimbetopsalis increased in size to the point where they were as large as modern-day beavers. This new species has no living descendants, but it is one of the longest-living mammals, having lived for 160 million years.

"Finding this new mammal was a pleasant surprise. It helps fill an important gap in the record of this group of mammals. It's interesting that this odd, now extinct group, was among the few to survive the mass extinction and thrive in the aftermath," Dr. Thomas Williamson, from the New Mexico Museum of Natural History and Science, said in a news release. "It may be because they were among the few mammals that were already well-suited to eating plants when the extinction came. This new species helps to show just how fast they were evolving to take advantage of conditions in the post-extinction world."

Among the fossils recently found were Kimbetopsalis teeth and skull fragments. They were excavated during an archeological dig last summer in a remote desert of New Mexico. Carissa Raymond, a sophomore at the University of Nebraska, was on her first dig when she found the fossils.

"When Carissa found this thing and brought it to me, I instantly suspected it was new," Williamson said in a news release. "I'd never seen anything like this before."

The researchers noted that they believe Kimbetopsalis could have suffered from competition with rodents, which emerged 57 million years ago.

Their findings were recently published in the Zoological Journal of the Linnean Society.  

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