Last year, the world was stunned when a new human ancestor, Homo naledi, was unearthed and described in a South African cave named “Rising Star”. The vast array of fossil evidence suggested H. naledi buried its dead, which is a ritual often thought to have been exclusive to our own species.
At the time, based on similarities with other ancestral Homo species around at the time, H. naledi was dated to be around 2 million years old. This means it just about predates the appearance of H. erectus, a prominent ancestor of ours that is the first known to use complex stone tools, including hand axes. However, a new study in the Journal of Human Evolution has revised this date down considerably.
This new team of researchers carefully compared the features of the skulls and teeth of the H. naledi fossils to those of all known hominids, living or extinct. By looking at incremental changes in skeletal structures over time, they calculated that H. naledi is far, far younger than previously thought.
“H. naledi might be less than a million years old,” Mana Dembo, a paleoanthropologist at Simon Fraser University and lead author of the study, told ScienceNews. More precisely, it appears that H. naledi is in fact just 912,000 years old.
This chronological reassignment certainly changes the story of human evolution, and at the very least suggests that ritualized behaviors do not extend back in time as far as we thought. The burning question, then, is where did H. naledi fit into this chaotic evolutionary tree?
A comparison of the skulls of several members of the Homo genus, including H. naledi, far right. Natural History Museum, UK/Wikimedia Commons; CC-BY-4.0