Deep in a South African cave, scientists discovered 15 partial skeletons of a new species of human, Homo naledi. According to the British Broadcasting Corperation, the new species, which lived as long as three million years ago, has a smaller head than Homo sapiens, but more modern teeth, feet and hands, bridging a gap between primitive and modern humans.

Discovered in a tunnel eight inches wide, called Superman’s Crawl, the skeletons were found arranged in a manner consistent with a burial, a modern, human-like ritual. Burial was formerly thought to be limited to modern humans.

“Not only did they have 15 individuals, but when you put them all together you get almost a complete skeleton,” says Lisa Whitenack, assistant professor of biology.

It is unknown how the skeletons ended up in Superman’s Crawl, given the size of the tunnel. Researchers did not find bite marks on the bones, which would indicate predators dragging the dead into the den.

“They think it’s a burial site. It doesn’t look like a predator den, which was a very viable possibility,” Whitenack says.

Naledi’s apparent burial is significant in the evolutionary development of Homo.

“It’s a cultural shift—burial—that defines them as another species, in my opinion,” said Lacey Rzodkiewicz, ’17, a biology major.

While the manner in which naledi handled their dead signifies a significant change in culture, there are major morphological differences between them and other Homo species.

“The discovery is a mix of features from our genus, Homo, and Australopithecus, which came before Homo,” says Whitenack. “I never would have guessed that as a logical development in evolution.”

Naledi has hands that are identical, or at least similar, to humans. Its fingers, however, are far more curved, suggesting the species was capable of using tools and climbing.

While its fingers are somewhat different, naledi’s feet are identical to those of humans. This suggests that it was capable of walking long distances.

“Its skull is definitely more similar to some of the older specimens,” Whitenack says.

The BBC reports that naledi’s braincase is about the size of an orange, about half the size of a modern human’s. This is a change from evolutionary trends, as Homo habilis, which lived about as long ago as some researchers estimate naledi, had a much larger brain. In fact, naledi’s brain is similar to that of a gorilla.

If naledi’s braincase makes the species differ from the rest of Homo, then its jaw highlights its similarities. Naledi’s teeth, which are nearly identical to humans, are smaller than its supposed ancestors.

“This seems like an interesting development,” says Heather Bosau, ‘17. “It’s a step forward and backwards at the same time.”

While evolution, and especially human evolution, is not a straight line but a process with progress and setbacks, naledi adds an aspect of confusion into the equation. With naledi’s morphological and cultural features that are similar to those of modern humans, the newly discovered species epitomizes, rather than contradicts, evolution.