Were there humans in Europe 6 million years ago?

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Since the discovery of the first Australopithecus fossils in southern and eastern Africa in the mid-20th century, the origin of the human lineage has been located on the black continent. Other fossils discovered in the same region, including the famous Laetoli footprints in Tanzania, left 3.7 million years ago by human-like feet, further reinforced the idea that the first members of our lineage did not just originate in Africa, but remained isolated there for several million years, before dispersing throughout Europe and Asia.

But that idea could be wrong. In fact, the discovery of a row of human-like footprints on Crete, dating back at least 6 million years, has come as a surprise to paleontologists, as it does not agree with the concept of African origin and suggests a much more complex reality.

The footprints were discovered by chance in 2002 by Gerard Gierlinski, a Polish paleontologist specializing in fossil footprints, while on vacation in Crete. But it was not until 2010 that he studied them thoroughly and concluded that they had been left by a hominin. In 2017, Per Ahlberg, from Uppsala University, took up the research and published its surprising findings. “This finding,” Ahlberg said then, “directly challenges the established account of the evolution of early humans, and is likely to generate much debate. It remains to be seen whether the community of researchers studying the origin of humans will accept these fossil footprints as evidence of the presence of hominins on Crete during the Miocene.

Now an international team of researchers from Germany, Sweden, Greece, Egypt and England, led by the scientists Uwe Kirscher and Madelaine Boehme, from the Senckenberg Center for Human Evolution and the Paleoenvironment of the University of Tübingen, has just contributed new data that points directly to the ‘human’ origin of these footprints. His study has just been published in the magazine ‘
Scientific Reports
‘.

Using geophysical and micro-paleontological methods, researchers have set the age of the footprints at 6.05 million years, making them the oldest direct evidence of a human-like foot used for walking. «The tracks are almost 2.5 million years older than the tracks attributed to the Australopithecus afarensis (Lucy) from Laetoli in Tanzania, ”says Uwe Kirscher. This places the Trachilos footprints in the same age range as the fossils of the Orrorin tugenensis from Kenya, which was already walking upright, although this was deduced from the shape of the femurs since no foot bones or footprints were found attributable to that species.

The dating of the Cretan footprints, therefore, constitutes a real treasure when it comes to studying how our first ancestors began to walk more than six million years ago. “The oldest human foot used to walk upright,” explains Per Ahlberg, a professor at Uppsala University and a co-author of the study, “had a ball, with a strong parallel big toe and successively shorter lateral toes. The foot had a shorter sole than Australopithecus. There was not yet a pronounced arch and the heel was narrower.

Six million years ago, Crete was connected to Greece through the Peloponnese. According Madelaine Boehme, “We cannot rule out a connection between the producer of the prints and the possible prehuman Graecopithecus freybergi.” Indeed, several years ago, Böhme’s team identified that previously unknown prehuman species in what is now Europe on the basis of fossils found in 7.2 million-year-old deposits just 250 kilometers away from Athens.

The work also confirms recent research and the theses of Böhme’s team, according to which six million years ago the European continent and the Near East were separated from humid East Africa due to a relatively brief expansion of the Sahara. Geochemical analysis of Cretan beach deposits from six million years ago suggests that dust from the North African desert was carried there by the wind. In that study, the team dated mineral grains the size of dust between 500 and 900 million years old.

According to Böhme, other recent research has also suggested that the African monkey Sahelanthropus could be ruled out as bipedal, and that Orrorin tugenensis, which originated in Kenya and lived between 6.1 and 5.8 million years ago, is the most pre-human. ancient from Africa. Thus, short-term desertification and the geographic distribution of early human predecessors may be more closely related than previously thought.

On the one hand, in effect, a stage of desertification that occurred 6.25 million years ago in Mesopotamia could have started a migration of European mammals, possibly including apes, to Africa. On the other hand, the second phase of the closure of the continents by the Sahara 6 million years ago could have allowed a separate development of the African Orrorin tugenensis in parallel with a European prehuman. According to this principle, called by Böhme ‘desert oscillation’, the successive short-term desertifications in Mesopotamia and the Sahara caused a migration of mammals from Eurasia to Africa.

What the new findings seem to be making increasingly clear is that the origin of our species is something much more complicated than was thought just a few years ago.

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