Newly excavated human bone fragments from Lanis, Germany. **tim schüler tlda。， cc by-nd
The idea that two different human species, Homo sapiens (us) and Neanderthals, coexisted in western Eurasia 50-40,000 years ago has long captured the imagination of academics and the public.
It is not surprising, then, that this period—the Middle and Late Paleolithic transitions—has been the focus of research by many archaeologists, physical anthropologists, and, more recently, geneticists.
Over the years, a variety of scenarios have been explored, from those that assume tens of thousands of years of coexistence between the two groups of humans, to those that see Homo sapiens replace Neanderthals more quickly – whether through the active or coincidental displacement of our cousins, or by competing with them for resources.
Both positions allow for occasional hybridization, which leads to the presence of a bit of Neanderthals in many of us, especially those of European and East Asian descent.
However, there are many challenges to exploring this distant era. Human skeletal remains are relatively rare, and many of the most famous fossils were excavated in less than ideal conditions in the 19th and early 20th centuries.
When skeletal remains are found, people tend to question their exact relationship to other archaeological remains at the same site, such as stone and bone tools, animal remains, and other finds. It is often believed that there is a link between a particular species of human being and the species found in excavations, but it is later found to be false in many cases.
The transition period of 50-40,000 years ago is within the lower limit of radiocarbon dating, and this technique is only suitable for organic remains about 50,000 years ago. This means that the smallest amount of recent contamination from burial environments or museum-protected materials can make dating of these sites extremely challenging.
This has led to major revisions to the chronology of early human occupation over the past decade, delaying some dates of Neanderthals and modern human remains by thousands of years.
This is obviously crucial to the debate, as it is impossible to talk about overlap or substitution without a strong chronology. There is also the question of spatial scale. For example, did the persistence of Neanderthals in southern Iberia 40,000 years ago represent a long period of overlap and coexistence, or was it the "last stop" on the continental margin, explicitly avoiding contact with newcomers?
The most recent to enter the battle is the Ilsenholler Cave in Lanis, east-central Germany, which sits at the base of a 16th-century Renaissance castle and has its origins in the early Middle Ages.
An international multidisciplinary team has identified human (Homo sapiens) remains from the early 20th century and more recently excavated in the cave, dating back to about 45,000 years ago. When combining the early dates of Homo sapiens in France and various dates of Neanderthals over 45,000 years across Europe, this makes the potential overlap between the two species last about 10,000 years, the authors say.
In a companion**, the researchers reported the results of their analysis of stable oxygen isotopes (different chemical forms of an element) from teeth belonging to mammals belonging to the equine family (equidae). These teeth come from the same level of sediment as human remains. As a result, people were subjected to a special cold snap about 45-43,000 years ago.
The remains of Homo sapiens are associated with what was previously thought to be an ambiguous stone tool industry (a special way of making tools) called Lincombian-Ranisian-Jerzmanowician (LRJ). But it is not clear whether these were made by Neanderthals or modern humans.
Cave ruins in Ilsenh Hle. **tim schüler tlda， cc by-nd
Mysterious tool maker.
Other transitional Middle and Upper Paleolithic stone tools have a long history of the same problem – we are not sure who made it. The most striking are the ch telperronian in the south of France and in the north of Spain: the remains of Neanderthals accompany the tool industry in these "modern looks", does this mean that they were tool makers, or were they a fortuitous connection?
The controversy continues, with the recent discovery of a possible ilium in the iliac of a newborn baby of Homo sapiens in the Ch Telperronian assemblage of the Grotte du Renne in Archy-sur-Cure, central France. Here, previously only Neanderthal remains were found.
For thousands of years, most of the caves of Paleolithic sediments have undergone intermittent occupation, often occupied by Neanderthals and Homo sapiens. Materials are easily mixed together, so it is difficult to say who made them, except for finding tools buried in the graves of modern humans. Lanis does seem to have an advantage in this regard, though, as the levels containing human remains and LRJ tools are sealed together by falling rocks.
However, even here, a warning should be issued. The dates at all levels considered still span thousands of years, during which it is likely that both camps made short-term visits.
Lanis's findings, as well as providing important new data for our understanding of the Upper Paleolithic Transition, highlight the contribution of recent developments in archaeological science.
Lanis is far from excavating a complete skeleton or skull, which traditionally heralds an important Neohominin fossil, and he produced only a few small bone fragments that can be identified as human. Some other small bone fragments have been identified as belonging to hominin (a broader family of humans) using a technique called proteomics – the study of genus, sometimes species-specific protein structures. In another companion**, this technique is also applied to the fauna of the site.
Then, radiocarbon dating with relative high accuracy was obtained, both at the level of the sediment and on the human remains themselves. The accuracy of these dates was further improved through statistical modeling.
But most importantly, for the question at hand, ancient DNA analysis – in this case, mitochondrial DNA (mtDNA) – confirms the identification of Homo sapiens. The mtDNA results linked Ranis to other Upper Paleolithic human remains in Zlatk Ň in the Czech Republic and Grotta di Fumane in Italy.
An interesting twist on this story, as noted by the authors of the Lanis study, is that recent genetic studies have shown that the Homo sapiens who made these early forays into Europe appear to have been replaced by other populations of Homo sapiens in the Upper Paleolithic.
Thus, the Upper Paleolithic transition and its substitution for one hominin population may have to be expanded to account for similar subsequent events, which remain less obvious because they all involved Homo sapiens.