Nearly Neanderthal: Skulls Reveal the Steps in Human Evolution

By admin-s Last updated Jun 20, 2014

(NBC News) – The current estimate is that the bones are at least 430,000 years old — which is consistent with the view that they’re on the branch of the family tree leading to Neanderthals, but not there yet.

Skulls found in a Spanish cave suggest that the physical features of Neanderthals and humans diverged in stages, starting with the face and teeth, researchers reported Thursday.

“It is now clear that the full suite of Neanderthal characteristics didn’t evolve at the same pace,” said Juan-Luis Arsuaga, a paleontologist at the Complutense University of Madrid and the lead author of a study published in this week’s issue of the journal Science.

In the report, Arsuaga and his colleagues lay out their scenario for human evolution, based on an analysis of 17 reconstructed skulls found deep within the Sima de los Huesos cave in Spain. Arsuaga said the findings were consistent with a “Game of Thrones” evolutionary saga, with communities (or “houses”) of humans and their distantly related kin competing for habitat more than 400,000 years ago.

Winter was coming

During that era, glaciers were creeping southward from northern Eurasia, adding to the evolutionary pressure on different groups of hominins — a category that includes modern-day Homo sapiens, now-extinct Neanderthals and other humanlike species. “Winter is coming,” Arsuaga said, echoing the motto associated with one of the houses on “Game of Thrones.”

The pressure to survive probably caused communities with advantageous traits to gain more of a foothold amid violent conflicts with other groups. “It was not a matter of a gradual and slow, generation-after-generation accumulation of small changes by the entire European population,” Arsuaga told NBC News during a teleconference on Thursday.

Some Neanderthal-like traits are reflected in the skulls from the Spanish cave. For example, they had protruding front teeth, and the joint for the jaw was relatively low. To modern eyes, their chin would have looked weak or even non-existent.

“It seems these modifications had to do with an intensive use of the frontal teeth,” Arsuaga said in a news release. “The incisors show a great wear, as if they had been used as a ‘third hand,’ typical of Neanderthals.”

The Sima de los Huesos hominins may have used their front teeth “to grasp things, possibly meat … and they were cutting into pieces,” Arsuaga told reporters Thursday.