The Neanderthals knew how to make an entrance: teeth first. Our sister species' distinctive teeth were among the first unique aspects of their anatomy to evolve, according to a study of their ancestors. These early Neanderthals may have used their teeth as a third hand, gripping objects that they then cut with tools.
The claim comes from a study of fossils from Sima de los Huesos in northern Spain. This "pit of bones" may be an early burial site, and 28 near-complete skeletons have been pulled from it, along with a large hand-axe that might be a funeral gift.
The hominins in the pit look like Neanderthals, but are far too old. That suggests they are forerunners of the Neanderthals, and if that is the case they can tell us how the species evolved.
To find out, Juan Luis Arsuaga Ferreras at the UCM-ISCIII Joint Centre for Research into Human Evolution and Behaviour in Madrid, Spain, and colleagues studied 17 of the skulls. They found that the brain case was still the same shape as in older species. But the skulls' protruding faces and small molar teeth were much more Neanderthal-like.
This suggests the earliest Neanderthals used their jaws in a specialised way. It's not clear how, but it probably wasn't about food, says Ferreras. "There are no indications of any dietary specialisation in the Neanderthals and their ancestors. They were basically carnivores."
Instead, Ferreras suggests the first Neanderthals used their teeth to grip objects, giving them two hands free – one to steady the object and the other to cut it with a tool. "We guess that they were grasping a big piece of meat with the front teeth and cutting it into smaller pieces," he says. Many of the Sima front teeth have been scratched by tools, suggesting they sometimes missed.
The alternative is that their faces changed shape by sheer accident, says Jean-Jacques Hublin at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. "Some of these facial features might essentially have been fixed at random by genetic drift."
Last year, researchers extracted DNA from a 400,000-year-old bone from Sima de los Huesos. Unexpectedly, the DNA was similar to that of Denisovans, a little-known Asian group that lived much more recently. This suggests Neanderthals and Denisovans evolved from a common ancestor much like the Sima people, long after that ancestor split from us.
Journal reference: Science, DOI: 10.1126/science.1253958
If you would like to reuse any content from New Scientist, either in print or online, please contact the syndication department first for permission. New Scientist does not own rights to photos, but there are a variety of licensing options available for use of articles and graphics we own the copyright to.