A skull fragment 2 million years old comes from the earliest baboon ever found, a study reports. The fossil — shown at left compared with later baboons — was found in Malapa, a cave in South Africa where specimens of Australopithecus sediba, an early ancestor of modern humans, were discovered in 2010. The ancient baboon, Papio angusticeps, is the first nonhominin primate found there.

The baboon bore a strong resemblance to its modern descendants, said Christopher Gilbert, an anthropologist at Hunter College in New York and an author of the study published in PLOS One. “You’d be hard pressed to figure out the difference between this fossil and a skull of a living baboon,” he said. The finding will help researchers to more accurately date fossil sites.

New York Times