What Can We Learn From Homo naledi’s Skull?

(Illustration by Andrew Howley)

After the excitement of Homo naledi’s discovery and extraction from deep in a narrow cave in South Africa, and the implication that these non-humans may have intentionally carried their dead deep into the earth, we are left with the bones themselves, what they tell us about these creatures, and what new questions they inspire.

These sketches and notes come from interviews and conversations during both the 2013 Rising Star Expedition and the 2014 workshop where established experts and early-career scientists came together to analyze the 1,550 fossil pieces.

The Skull

Modern humans have a very large, high-arching, round cranium (or brain case), and the mandible (or lower jaw), is positioned directly below the front half of the skull.

A very early hominin like an australopithecine (“southern ape”) such as Lucy, has a much smaller, almond-shaped cranium (not that there’s much of Lucy’s actual cranium to go by—this comes from other specimens), with the mandible jutting out in front of the face.

Homo naledi is in the interesting position of having a very small skull, but a very round one, and there is only a shallow slope down from the nose to the teeth.

This is similar to what is seen in Australopithecus sediba, also found by Lee Berger nearby, which while not in the genus Homo, shares more skull shape traits with us than with other australopiths. (Quick Guide: Know Your Hominid Skulls)

That roundness of the skull and flatness of the face are both related to having smaller teeth and chewing muscles, relative to our other relatives. So they probably ate more like us than say chimps or gorillas do.

N.B. on Nose Bones

The jaw changes have other impacts on our facial appearance as well. Instead of thinking that human noses jut out while other ape noses lie flat, to a certain extent you can actually —> Read More