Human evolution involved overlapping eras, new research finds

New evidence uncovered in Spain has revealed that Neanderthals survived in the area long after Neanderthals died out in other parts of the world. The findings support the notion that human evolution was more complicated and uneven than previously thought.

A 10-year excavation uncovered the remains of three Middle-Paleolithic sites in southern Spain that showed evidence of Neanderthals at least 3,000 years after Neanderthals were thought to have died off.

The researchers recently published their findings in the journal Heliyon.

The Middle-Paleolithic Period was part of the Stone Age and dates back from 300,000 to 30,000 years ago. It was during this time that modern humans interbred with Neanderthals and other Eurasian populations.

The researchers used radiocarbon and luminescence dating to track artifacts that were found in the sites. Luminescence dating is a precise dating method that can tell archaeologists exactly when certain events occurred.

In this case, the excavations and dating pointed to a Neanderthal presence.

“In three new excavation sites, we found Neanderthal artifacts dated to thousands of years later than anywhere else in Western Europe,” said Dr. João Zilhão, the lead author of the study. “Even in the adjacent regions of northern Spain and southern France the latest Neanderthal sites are all significantly older.”

One of the most interesting aspects of the discovery is that it gives a more accurate picture of how and when Neanderthals were absorbed into modern human populations through interbreeding.

This interbreeding was not a smooth process that happened everywhere at once, but instead was an uneven “stop and go” process that differed depending on geographic regions.

“We believe that the stop-and-go, punctuated, uneven mechanism we propose must have been the rule in human evolution, which helps explain why Paleolithic material culture tends to form patterns of geographically extensive similarity while Paleolithic genomes tend to show complex ancestry patchworks,”  said Dr. Zilhão.

There is certainly more about human evolution left to discover, particularly when it comes to Neanderthals, and excavating new sites may be the key to unearthing that information.

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By Kay Vandette, Earth.com Staff Writer