Fossil teeth push the human-Neandertal split back to about 1 million years ago

CROWNING ROOTS An analysis of hominid tooth evolution, including specimens from Spanish Neandertals (top row), pushes back the age of a common Neandertal-human ancestor to more than 800,000 years ago. The bottom row shows Homo sapiens teeth.

People and Neandertals separated from a common ancestor more than 800,000 years ago — much earlier than many researchers had thought.

That conclusion, published online May 15 in Science Advances, stems from an analysis of early fossilized Neandertal teeth found at a Spanish site called Sima de los Huesos. During hominid evolution, tooth crowns changed in size and shape at a steady rate, says Aida Gómez-Robles, a paleoanthropologist at University College London. The Neandertal teeth, which date to around 430,000 years ago, could have evolved their distinctive shapes at a pace typical of other hominids only if Neandertals originated between 800,000 and 1.2 million years ago, she finds. 

Gómez-Robles’ study indicates that, if a common ancestor of present-day humans and Neandertals existed after around 1 million years ago, “there wasn’t enough time for Neandertal teeth to change at the rate [teeth] do in other parts of the human family tree” in order to end up looking like the Spanish finds, says palaeoanthropologist Bernard Wood of George Washington University in Washington, D.C.

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