UW Biology Professor Gregory Wilson Mantilla was featured in an article in National Geographic about the earliest-known fossil evidence of primates. The oldest known primate fossils were dated to just after the extinction event 66 million years ago—suggesting some primate ancestors lived even longer ago.

Shortly after an asteroid strike triggered a cataclysmic extinction event 66 million years ago, a group of mammals with a proclivity for climbing trees and eating fruit began to thrive. These animals—the early relatives of primates—would give rise to a lineage that led to the first monkeys, including great apes such as gorillas, chimpanzees, and eventually, humans.

Now, scientists have discovered fossils of the oldest known primate among a cache of unusual teeth tucked away in a museum drawer for decades. Some of these teeth, recently described in the journal Royal Society Open Science, belonged to the new species Purgatorius mckeeveri, a pint-sized precursor to modern primates that lived 65.9 million years ago, just 100,000 years after the extinction event at the end of the Cretaceous period.

“It reconfigures our view of evolution,” says Gregory Wilson Mantilla, lead author of the study and a biology professor at the University of Washington who studies early mammals.

The discovery also bolsters a theory that the ancestors of primates lived alongside the dinosaurs—and somehow survived the extinction event that killed off about three-quarters of life on Earth. Two of the teeth in the new study belonged to a second, previously known species, Purgatorius janisae, which also lived 65.9 million years ago. And if two ancient primate species existed at this time, some unknown animal must have come before.

Read the full article in National Geographic.