Homo naledi’s brain may have been small, but it looked surprisingly similar to ours, according to a new study which suggests that structure may have come before size in the evolution of hominin brains.

Measurements of skull fragments indicate that Homo naledi’s brain was about the same size as that of an Australopithecine—the genus of primates that lived in Africa 2 to 4 million years ago and may be among our early ancestors. Yet the diminutive species was present in Africa long after the Homo lineage appeared and may have overlapped with modern humans. So how it fits in to our family tree is not clear.

A new study reveals that, despite the size, Homo naledi’s brain looked quite different from Australopithecus’ and much more like ours, at least in some very important areas.