Neandertal to Modern Transition Full of Fits and Spurts

New evidence suggests that Neandertals survived longer on the Iberian peninsula than elsewhere in Europe.  The redating of the Zafarraya Neandertal from the late 20k's to between 38 and 40 ky saw a revision of theories about Neandertal extinction. Now more evidence has been unearthed suggesting that this window is more secure.   From The Statesman:

Neanderthals may have survived at least 3,000 years longer than thought in what is now Spain – much after the species had died out everywhere else, a study has found.

The findings suggest that the process of modern human populations absorbing Neanderthal populations through interbreeding was not a regular, gradual wave-of-advance but a “stop-and-go, punctuated, geographically uneven history.”

Over more than ten years of fieldwork, researchers excavated three new sites in southern Spain, where they discovered evidence of distinctly Neanderthal materials dating until 37,000 years ago.

“Technology from the Middle Paleolithic in Europe is exclusively associated with the Neanderthals,” said Joao Zilhao, from the University of Barcelona in Spain.

“In three new excavation sites, we found Neanderthal artefacts dated to thousands of years later than anywhere else in Western Europe,” said Zilhao, lead author of the study published in the journal Heliyon.

It seems pretty clear now that the model of rapid replacement of Neandertals does not hold. This kind of evidence, along with sites such as Lagar Velho, suggest that the transition, at least in this region was long-term, with much hybridization.  We still do not know exactly how long Neandertals persisted in this region.  It makes perfect sense that they would have been the last ones to undergo the transition (however that happened) because the earliest Aurignacian sites, associated with modern humans, occur in far eastern Europe as the wave of moderns came through during the Würm I/Würm II interglacial.

The question that I have is why didn't the earliest modern humans, represented by the Jebel Irhoud remains, come through the Strait of Gibraltar?  North of that, all you find are archaic, all the way down to the Zafarraya remains.  I wonder why this is.

New Investigations at the Sima de los Huesos Cave in Atapuerca: Kind of Neandertal and Kind of Not

Science Daily is reporting on a new paper in Science, about the conclusions drawn from the largest single cache of human remains in one place in Europe, the Sima de los Huesos cave, near Atapuerca, in Spain.  They write:

“With the skulls we found," co-author Ignacio Martínez, Professor of Paleontology at the University of Alcalá, added, "it was possible to characterize the cranial morphology of a human population of the European Middle Pleistocene for the first time.”

About 400 to 500 thousand years ago, in the heart of the Pleistocene, archaic humans split off from other groups of that period living in Africa and East Asia, ultimately settling in Eurasia, where they evolved characteristics that would come to define the Neandertal lineage. Several hundred thousand years after that, modern humans -- who had evolved in Africa -- settled in Eurasia, too. They interbred with Neandertals, but even then showed signs of reproductive incompatibility. Because of this, modern humans eventually replaced Neandertals.

This is the hybrid depression that I mentioned a few posts back.  This model fits the genetics information that was summarized by Dennis Venema in his BioLogos post on palaeogenomics from a few weeks ago.  It still also fits with the idea that modern humans swamped a Neandertal genome that was already subject to selective disadvantage.  Consequently, by around 27-29 ky BP, the last populations of Neandertals are, perhaps represented by Zafarraya, a late surviving Neandertal from the very southern coast of Spain. The idea that this Neandertal represents a refugium has been kicked around for decades. Critically, the earliest moderns in Central Europe predate this “last neandertal” by between five and nine thousand years and the evidence from Lagar Velho, in Portugal, indicates that hybridization was occurring as late as this. 

Discovery News Reports on “Neandertals’ Last Stand”

Disovery News reports on the excavation of the Mousterian site of Byzovaya, in Russia, in the Ural Mountains that has been dated to 33,000 years ago. Jennifer Viegas writes:

A Neanderthal-style toolkit found in the frigid far north of Russia's Ural Mountains dates to 33,000 years ago and may mark the last refuge of Neanderthals before they went extinct, according to a new Science study.

Another possibility is that anatomically modern humans crafted the hefty tools using what's known as Mousterian technology associated with Neanderthals, but anthropologists believe that's unlikely.

"We consider it overwhelmingly probable that the Mousterian technology we describe was performed by Neanderthals, and thus that they indeed survived longer, that is until 33,000 years ago, than most other scientists believe," co-author Jan Mangerud, a professor emeritus in the Department of Earth Sciences at the University of Bergen and the Bjerknes Centre for Climate Research, told Discovery News.

Even before I got to the bottom of the article and saw Erik Trinkaus’ comments, I was thinking “What about the Neandertal site of Zafarraya, which is certainly 31,700 and possibly as recent as 27,000?” I think this does extend the range of the late Neandertals but there is scant evidence that this is their last stand.

The Last Neandertals and Climate Change

Joao Zilhao is now suggesting that the last surviving Neandertals had to have died out around 37 ky, rather than 27 ky which is what has been thought for the last several years. According to a story in Yahoo News:

The paper, by Professor Zilhao and colleagues from the University of Bristol, revealed new dating evidence for the Late Aurignacian of Portugal, an archaeological culture associated with modern humans, which firmly constrains the age of the last Neanderthals of southern and western Iberia to some 37,000 years ago.

This new evidence puts the duration of the Iberian Neanderthal refugium at five millennia, and counters speculations that Neanderthal populations could have remained in the Gibraltar area until 28,000 years ago.

These findings have important implications for the understanding of the archaic features found in the anatomy of a 30,000-year-old child unearthed at Lagar Velho, Portugal.

This will be hard to square with Zafarraya as well. The stone tool assemblages from that site are clearly Mousterian with, as Jean-Jacques Hublin writes: "little or no Upper Palaeolithic influence." I also think that Erik Trinkaus' analysis of the Lagar Velho remains, is very close to the mark. I simply do not think that it is credible to view the remains as that of a "chunky Gravettian kid."

I wonder if this will revive the incredible dust-up that followed, regarding the analysis of the Lagar Velho remains. I challenge anyone out there to find Erik's original post. It seems to have vanished into the ether.

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