Oldest human fossils north of the Alps

Ilsenhöhle and stone blades

The Ilsenhöhle is located under Ranis Castle in Thuringia; Right: Two stone blades found in the cave. © Tim Student, TLDA / Josephine Schubert, Burg Ranis Museum

When did the first representatives of Homo sapiens reach Central Europe? The oldest known finds of our human species came from the Balkan region. But now around 45,000 year old bone fragments from the Ilsenhöhle in Thuringia prove that our ancestors settled the area north of the Alps earlier than expected. Although the climate at that time was still arctic cold and the landscape resembled a cold steppe, small groups of Homo sapiens were already living and hunting there. This shows that our species adapted better and earlier to the European Ice Age climate than previously thought. In addition, the new analyzes reveal that a special form of stone tools, the so-called Lincombian-Ranisian-Jerzmanowician, was created not by Neanderthals, but by Homo sapiens.

Around 45,000 years ago, a momentous change began in Europe: a new human species, Homo sapiens, migrated from Africa via the Middle East and the Balkans to Europe and replaced the Neanderthals who had previously lived there. But exactly when the first representatives of our ancestors came to Europe is only partially clear, because only a handful of Homo sapiens fossils from this time were found in Europe, the majority of them in southeastern Europe. The oldest known finds include human bone remains that are around 45,000 years old from the Bacho Kiro Cave in Bulgaria and a jawbone that is almost 41,000 years old from the Pestera cu Oasis, a cave in Romania. However, it remained unclear whether these early Homo sapiens representatives had already penetrated further north. Also controversial was the attribution of some blade-shaped stone tools, some of which were worked on both sides, that were found in the Czech Republic, Poland, Germany and Great Britain. This so-called Lincombian-Ranisian-Jerzmanowician technocomplex (LRJ) dates back to the transition period from Neanderthals to Homo sapiens. But which of the two created these tools has not yet been clearly determined.

piece of bone
This is one of the approximately 45,000 year old pieces of Homo sapiens bone from the Ilsen Cave. © Tim Student TLDA CC-by-nd 4.0

Searching for clues in the Ilsenhöhle

Now new finds in a cave in Thuringia provide answers to some of these questions. The Ilsen Cave near the town of Ranis in the Orla Valley has been known since the 1930s as a place where LRJ stone tools, animal bones and human fossils were found. Excavations were already being carried out in the limestone cave back then. An international research team led by Jean-Jacques Hublin from the Max Planck Institute for Evolutionary Anthropology and Tim Student from the Thuringian State Office for Monument Preservation and Archeology in Weimar has now re-examined the cave's soil layers. The aim was to look for relics of previous inhabitants of this cave and thus the potential creators of the LRJ tools and to classify the finds more precisely in time. “The challenge of the excavation was to examine a complete eight-meter-thick sediment sequence and identify the layers of the LRJ. It was also not at all clear whether there were still enough sediments to support finds after the excavations in the 1930s,” reports co-senior author Marcel Weiss from the University of Erlangen-Nuremberg.

But the painstaking work was successful: “Fortunately, we came across a 1.7 meter thick boulder that no one was digging under at the time,” reports Weiss. “After manually crushing and removing this collapsed block of the former cave roof, we were able to reach the important layers of the LRJ, which also contained human bone fragments. That was a big surprise.” However, the bones were broken into such small pieces that anatomical classification was not possible. The team therefore used a combination of proteome analyses, DNA comparisons and isotope analyzes to characterize the findings. It turned out that the tiny pieces of bone came from four different individuals - all representatives of Homo sapiens. In reanalyses of ancient bone fragments discovered during the earlier excavation, the team identified nine additional individuals.

Settlement as early as 45,000 years ago

But how old are these finds? To find out, the researchers dated the human bone finds and animal bones from the various layers using radiocarbon dating. It turned out that the layers associated with the human bones and the LRJ tools are between 43,360 and 47,500 years old and therefore come from the same time and from the same human species. “It is now certain that stone tools thought to have been made by Neanderthals are now definitely made by modern humans,” explains Hublin. Genetic dating using comparisons of mitochondrial DNA from human bones produced a similar result: “The genetic data of the mtDNA genomes from Ranis are between 49,105 and 40,918 years ago,” reports the team led by first author Dorothea Mylopotamitaki from the Max Planck University. Institute for Evolutionary Anthropology.

This makes the bone finds from the Ilsen Cave among the oldest known relics of Homo sapiens in Europe - and they are the earliest evidence of the presence of our ancestors north of the Alps. “The Ranis site provided evidence of the first expansion of Homo sapiens into the northern latitudes of Europe,” says Hublin. “This fundamentally changes our knowledge of the transition period, as it is now clear that anatomically modern humans reached northwestern Europe long before the Neanderthals disappeared in southwestern Europe.” When the first representatives of Homo sapiens reached Central Europe, they probably also encountered groups of the Neanderthals. The DNA comparisons also revealed that the people from the Ilsen Cave were closely related to each other and, interestingly, also to the human fossil of the “Woman from Zlaty kun” in the Czech Republic, which is also 45,000 years old. According to the researchers, this suggests that the people who reached Central Europe at the time were closely linked to the first populations of Homo sapiens in southeastern Europe.

Adapted to the cold early on

Additional analyzes of animal bones and isotopes also provided clues about the climatic conditions these first Homo sapiens groups faced in Central Europe. Accordingly, there was a very cold continental climate back then; it was on average five to 15 degrees colder than today. The landscape was characterized by an open cold steppe, similar to those in today's Siberia or northern Scandinavia. “Until now, it was assumed that humans' resistance to cold climate conditions only emerged several thousand years later. “Our result is therefore quite surprising,” says Sarah Pederzani from the MPI for Evolutionary Anthropology, lead author of an accompanying study on the paleoclimate in the Ilsenhöhle area. “Our results show that even these early Homo sapiens groups, when they spread across Eurasia, were already able to adapt to such harsh climatic conditions.” The animal bones from the Ilsen Cave suggest that humans were probably before mainly hunted larger Ice Age animals such as reindeer, woolly rhinoceros and horses.

Taken together, these finds and results represent an important breakthrough in the reconstruction of the settlement of Europe by our ancestors. “The results from the Ilsenhöhle in Ranis have fundamentally changed our ideas about the chronology and settlement history of Europe north of the Alps,” says Student. This is a milestone in the study of the earliest advances of Homo sapiens into Central and Northern Europe during the transition from the Middle to the Upper Paleolithic.

Source: Dorothea Mylopotamitaki (Max Planck Institute for Evolutionary Anthropology, Leipzig) et al., Nature, doi:
Nature, 31 January 2024, doi: 10.1038/s41586-023-06923-7; Sarah Pederzani (MPI for Evolutionary Anthropology/Universidad de La Laguna) et al., Nature, doi: 10.1038/s41559-023-02318-z

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