by The idea that there are two different human species, Homo sapiens (us) and the Neanderthals, who lived in western Eurasia 50–40,000 years ago and have long captured the imagination of both academics and the public.
It is therefore not surprising that this time period – the Middle to Upper Palaeolithic transition – has become the focus of research for many archaeologists, physical anthropologists and, more recently, genealogists.
Various scenarios have been explored over the years, from those in which the two groups of people coexisted for thousands of years, to those that saw a much more rapid replacement of Neanderthal by H. sapiens – whether by actively or incidentally displacing our cousins, or by competing with them for resources.
Both positions allow for occasional interbreeding which has resulted in a bit of Neanderthal being present in many of us, especially those of European and East Asian ancestry.
However, exploring this distance presents many challenges. Human skeletal remains are quite rare, and many of the most famous fossils were excavated under less than ideal conditions in the 19th and early 20th centuries.
When skeletal remains are found, there are often questions about their exact relationship to other archaeological remains at the same site – such as stone and bone tools, animal remains and other finds. Links between specific human species and excavation finds are often assumed, but in some cases they are not discovered until later.
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The transition period of 50-40,000 years ago is within the lowest limits of radiocarbon dating – a technique that only works on organisms still up to 50,000 years old. This means that the slightest later contamination from the burial environment, or from museum conservation materials, can make dating finds from these sites very challenging.
This has led to major revisions to the chronology of early human occupation in the past decade, shifting some dates on Neanderthal and modern human remains by thousands of years.
This is obviously crucial to the debate, since it is impossible to talk about overlap or replacement without a solid chronology. There is also the matter of spatial scale. Does Neanderthal persistence after 40,000 years ago in southern Iberia, for example, represent a long period of overlap and coexistence, or a “last stand” on the edge of the continent, expressly avoiding contact with the newcomers?
The latest entry into the fray comes from the Ilsenhöhle cave in Ranais, east-central Germany, which sits impressively at the foot of a 16th-century Renaissance castle with earlier medieval origins.
An international multidisciplinary team identified people (H. sapiens) remains from the early 20th century and from more recent excavations in the cave, dating back to around 45,000 years ago. The authors say that, when combined with early dates of H. sapiens in France and different dates for Neanderthal present at 45,000 years across Europe, this allows for a possible overlap period between the two species lasting about 10,000 years.
In a companion paper, the researchers reported the results of their analysis of stable oxygen isotopes (different chemical forms of an element) from teeth belonging to mammals in the horse family (equids). These teeth came from the same sediment levels as the human remains. The results put the people in a very cold trap around 45-43,000 years ago.
The IS H. sapiens Remains are associated with what was previously considered an ambiguous stone tool industry (a distinct way of making tools) known as the Lincombian-Ranisian-Jerzmanowician (LRJ). But it was not clear whether these were made by Neanderthals or modern humans.
Makers of mysterious tools
Middle Upper transitional stone tool industries have a long history of the same stone tools – we are not sure who made them. The Châtelperronian of southern France and northern Spain is the most significant: do the Neanderthal remains accompanying some of these “modern” tool industries mean that they were the tool makers, or is the association fortuitous ?
This debate continues apace, as it can H. sapiens The ilium of a newborn child was recently identified in the Châtelperronian assemblage at the Grotte du Renne in Arcy-sur-Cure, central France. Here, only Neanderthal remains have previously been identified.
In most caves with Palaeolithic deposits there was intermittent occupation, often by Neanderthal and both H. sapiens, over thousands of years. Materials are easily mixed together and so, without finding tools buried in a modern human grave, it is difficult to say who made them. Ranis seems to have an advantage in this, however, as the levels where the human remains and the LRJ tools were sealed together were rockfalls.
However, even here a note of caution should be sounded. The dates for the levels still under consideration cover several thousand years, and both camps may have had short-term visits during that period.
New archaeological techniques
The results from Ranais, as well as adding important new data to our understanding of the Middle-Upper Palaeolithic transition, show what recent developments in archaeological science have highlighted.
Far from finding a complete skeleton or skull that would traditionally herald an important new hominin fossil, Ranis yielded only a handful of bone fragments that were recognizable as human. A number of small bone fragments belonging to hominins (the wider human family) have been identified using a technique called proteomics – the study of protein structures unique to genes and sometimes to species. This technique was also applied to the site slope in another companion paper.
Then, relatively high-precision radiocarbon dates were obtained for the sediment level and the human remains themselves. The accuracy of these dates was further improved through statistical modelling.
But most importantly for the question at hand, analysis of ancient DNA – in this case, mitochondrial DNA (mtDNA) – confirmed the identity as H. sapiens. The Ranais mtDNA results connect with other Early Upper Palaeolithic human remains at Zlatý kůň in the Czech Republic and the Grotta di Fumane in Italy.
As the authors of Ranis’ study note, an interesting twist to the story is that recent genetic studies suggest H. sapiens these early raids into Europe seem to have been replaced by others H. sapiens later Upper Palaeolithic populations.
Therefore, the focus on the Middle-Upper Palaeolithic transition and its replacement by one more hominin population may have to be broadened to consider similar events, which subsequently remained much less visible, because involved all of them with them. H. sapiens.
This article from The Conversation is republished under a Creative Commons license. Read the original article.
Rick Schulting does not work for any company or organization that would benefit from this article, does not consult with, own shares in, or is funded by any company or organization that would benefit from this article, and has disclosed no affiliations relevant after his academic appointment.
