Homo naledi said to be only 250,000 years old

A few years ago, archaeologists made a striking discovery: A new species of hominin that seemed to show a mix of both archaic and modern features that lived around 3 million years ago. It turns out that Homo naledi might be much younger than previously thought.

Homo naledi assembled skull [Credit: Berger et al. 2015]

In an interview with National Geographic magazine, Lee Berger, who studied the original discovery of the remains of the primitive human species deep in a cave in South Africa, has said that they have revised the estimates of just how old the fossils really are. While the initial estimates claimed that they were somewhere in the region of 3 million years old, they now think that they are more likely to be roughly 250,000 years old. 

When news broke of the discovery of Homo naledi, it reverberated throughout the scientific community. What stood out about the new species of hominin was the fascinating mix of features it displayed, unlike anything seen in other species. While the fossils displayed many aspects that would usually place it within the Homo genus – which includes not only ourselves, but Neanderthals and Denisovans – they also had some other, more primitive characteristics.

The size of the skull and the morphology of the ribcage, for example, was more closely matched to what we see in the more archaic australopiths, which evolved in Africa around 4 million years ago. But the shape of the cranium, size of the teeth, and the legs, feet, and ankles, are more similar to the genus Homo. In addition to that, there are other features, such as the gracile hands, that are like neither groups of hominins.

This mosaic of characteristics is unusual, and throws into question what we thought we knew about human evolution. It used to be thought that the large brain size and complex tool use evolved in step with smaller tooth dimensions and longer legs. But the small brained, long legged H. naledi seems to question this. And now the revision of the dates in which they lived jumbles things up a little further.

The main question now is how such an archaic species survived to such a late date. Berger says that their estimates for the date of the fossils is between 300 and 200,000 years ago, which is intriguing indeed. This is because our own species, Homo sapiens, is thought to have evolved at around this time in East Africa, with many now speculating as to whether the two species may have once met, and even musing as to whether we may have had a hand in their eventual demise.

It is incredibly important to note at this point that this is pure conjecture, but it is not without precedent. Europe was once inhabited by Neanderthals, Siberia by Denisovans, and Indonesia by the “hobbit” people until our species rocked up.

Author: Josh Davis | Source: IFL Science [April 26, 2017]