You can now read 10 articles in a month for free on BostonGlobe.com. Read as much as you want anywhere and anytime for just 99¢.

The Boston Globe

Nation

Skull fossil reveals tangled human roots

WASHINGTON — A 2 million-year-old flat-faced skull pulled from sandstones of East Africa has shored up claims that at least three species of early humans coexisted in an ‘‘evolutionary experiment’’ that saw an explosive brain-size increase paired with radically different faces, teeth, and jaws.

While the partial skull and two newly found jawbones look very different from modern humans, they match an enigmatic, nearly complete skull found 40 years ago that paleoanthropologists have struggled to fit into the human family tree.

Loading comments...

You have reached the limit of 10 free articles in a month

Stay informed with unlimited access to Boston’s trusted news source.

  • High-quality journalism from the region’s largest newsroom
  • Convenient access across all of your devices
  • Today’s Headlines daily newsletter
  • Subscriber-only access to exclusive offers, events, contests, eBooks, and more
  • Less than 25¢ a week