These and some closely related remains may indicate that these Middle Paleolithic holdouts were kissing cousins of nearby anatomically modern humans. Or maybe not.
We know that Neanderthals occupied all of Europe for over 125 thousand years during a period known (from the artifacts) as the “Middle Paleolithic.” During this time, modern humans had become well established (and were using a similar suite of artifacts known as “Middle Stone Age” technology) in Africa. Prior to 40,000 years ago modern humans … most by now possessing a distinctly different suit of artifacts … began to displace or replace the Neanderthals across Europe. Despite the fact that you will hear people argue over what this displacement or replacement event consisted of, it is most likely that over several thousands of years these small scattered groups of hunter gatherers interacted in a number of ways, and that this period in our history was fairly complex.
It is quite likely that many patches of Europe were simply disoccupied by Neanderthals for some reason or another … as one might expect during peirods of changing climate with a thinly scattered and highly mobile population … and when people came back to those particular valleys or subregions, it happened to be the moderns and not the Neanderthals. There may have been competitive, even bellicose interactions here and there, though there is not one shred of evidence to suggest this. Not a single Neanderthal has been found with a modern human hunting implement stuck in it’s skull, or visa versa. The demise of the Neanderthal was not a matter of Mr. Modern in the Dordogne with the Side Scraper.
The fact that we are what we refer to as “modern humans” and it is we, not the Neanderthals who ended up occupying Europe and West Asia causes most modern humans to assume that they (the Neanderthals) were doin’ it wrong, or that the modern humans had some special advantage over the Neanderthals. Could be. But it is also true that VHS beat Betamax, and most people use Windows and not Apple or Linux computers.
The story of this replacement is largely known through the artifacts, which are relatively common across Europe. This story shows a generally east to west movement of moderns, but with considerable spatial complexity, and with the modern human technology replacing the Neanderthal last in southern Iberia. During this time there is evidence of a sort of mixing of the technologies, indicating that there were long term and meaningful interactions between at least some groups of modern humans and Neanderthals.
The DNA evidence, both of modern populations and of ancient groups (including DNA from several Neanderthal bones) seems to indicate that there is no significant (or even insignificant,really) contribution of DNA to living human populations. However, this does not rule out interbreeding in these early days. The truth is that the modern humans that occupied Europe right after the replacement (e.g., 30,000 years ago) may have also contributed relatively little to modern European populations. There is probably more Central Asian blood in central Europe than Cro-Magnon blood. Like it or not, if you are European, Genghis Kahn is more likely to be your uncle than, say, King Arthur.
So this leaves thebones. The physical remains … the skeletal bits and pieces … mostly tell a story of distinct differences between modern humans coming from Africa and Neanderthals, but that is because most of the skeletons are not from the time period of likely interaction between groups in Europe. In the Middle East, where both types of human seemed to take turns occupying certain landscapes over several tens of thousands of years, there is not clear evidence of intermixing of the groups. But in the late European Neanderthal populations, there may be some evidence of the relationship between the groups getting … well, let’s just say it’s complicated.
The Iberian bone and tooth fragments mentioned above are linked to a larger sample that for the purposes of analysis have been grouped together to assess the possible relationships of these late Neanderthals and the anatomically modern humans that were contemporary with them. These remains are the subject of study in a paper just now coming out in the Proceedings of the National Academy of Sciences. The paper by Walker, Tibert, Lopez, Lombardi, Perez-Perez, Sapata, Ortega, Higham, Pike, Schwenninger, Zilhao and Mr. Neanderthal himself, Trinkaus is titled “Late Neandertals in Southeastern Iberia: Sima de las Palomas del Cabezo Gordo, Murcia, Spain” and concludes (from the abstract) the following:
Middle Paleolithic fossil human remains from the Sima de las Palomas in southeastern Iberia (dated to ≤43,000-40,000 calendar years before present) present a suite of derived Neandertal and/or retained ancestral morphological features in the mandibular symphysis, mandibular ramus, dental occlusal morphology, and distal hand phalanx. These traits are combined with variation in the mandibular corpus, discrete dental morphology, tooth root lengths, and anterior dental size that indicate a frequency difference with earlier Iberian and more northern European Neandertals. The Palomas Neandertals therefore confirm the late presence of Neandertals associated with the Iberian persistence of the Middle Paleolithic, but suggest microevolutionary processes and/or population contact with contemporaneous modern humans to the north.
What does it all mean? Well, the study is a bit technical, but in essence, measurements of these bits and pieces, in comparison with matched measurements from different samples of clear Neanderthals and modern humans, strongly indicates that these late-dated bones are indeed Neanderthals. But they differ in ways that might indicate genetic mixing with modern humans living to the north. Or, the variations in measurements might indicate local, in situ evolution in a relatively isolated population.
Will we ever be able to make a more definite statement than this? Yes, if more remains are found. It will never be able to say for certain exactly who was sleeping with whom and where and when (this is hard enough to do when all the actors in the drama are alive and kicking!) but with more physical, bony remains from this region it would be easier to suggest plausible scenarios for the last centuries of the existence on this earth of the Neanderthals.
Michael J. Walker, Josep Gibert, Mariano V. Lopez, A. Vincent Lombardi, Alejandro Perez-Perez, Josefina Zapata ́ ́ ́, Jon Ortega, Thomas Higham, Alistair Pike, Jean-Luc Schwenninger, Joao Zilhao, Erik Trinkaus, ̃ ̃ (2008). Late Neandertals in Southeastern Iberia: Sima de las Palomas del Cabezo Gordo, Murcia, Spain
Proceedings of the National Academy of Sciences