Editor’s Note: This story was initially published with the title “Team including Princeton anthropologist makes groundbreaking discovery on early human burial practices.” This story has been significantly updated with new information from the peer reviews revealed publicly shortly before initial publication. The original text can be found here.

Eight years after discovering a new species in the human lineage, the Homo naledi, a team of scientists from National Geographic working in collaboration with Princeton anthropology professor Agustín Fuentes announced their findings in a newly-reviewed preprint: Homo naledi buried their dead. Until now, burying the dead and other cognitive-based behaviors such as using symbols have only been linked with larger-brained Homo sapiens and Neanderthals.

The team also announced the discovery of rock engravings, which they believe to be created by Homo naledi, in the Rising Star cave system in South Africa.

But announcement in popular media such as the National Geographic, CNN, the front page of the New York Times, and a new Netflix documentary entitled Unknown: Cave of Bones was of preprints, which are first-drafts of studies prior to peer review. The flashy rollout became a source of controversy when critical peer reviews were published on July 12 — only five days before Unknown: Cave of Bones was released.