For a long time it seemed clear that the cradle of man and his closest ancestors was in Africa. However, fossil finds and footprints discovered in Greece in recent years suggest that there may have been possible human ancestors in Europe as well. When exactly the pre-human footprints found in Crete originated, scientists have now investigated in more detail. Their result: The human-like tracks are already 6.05 million years old and could therefore be the oldest evidence of a two-legged hominid.
Whether Australopithecus afarensis, Ardipithecus or Homo habilis: Most of the ancestors of man lived in Africa, where they developed from primeval primeval monkeys living on trees to two-legged prehumans and later to the first representatives of the homo genus. According to current theory, it was only these early humans who emigrated from Africa and also colonized other continents. But in recent years scientists in the eastern Mediterranean have discovered fossils and footprints that don’t seem to fit into this scenario. These include the 7.2 million year old lower jaw and tooth of Graecopithecus freybergi, an early prehistoric man who was discovered in Greece and Bulgaria in 2017.
Footprints with human features
Also in 2017, a research team at Trachilos in Crete found footprints that, according to the first dating, must have been made more than five million years ago – and that had some strikingly human-like features: “The morphology includes features that were previously considered unique to hominins, including a forefoot ball, a close-fitting and robust big toe that lies parallel to the second toe and increasingly shortening side toes ”, explain Uwe Kirscher from the University of Tübingen and his colleagues. These human-like peculiarities were combined with some primitive features such as the lack of a longitudinal arch, an overall shorter sole of the foot and a heel that is not as wide and pronounced as in modern humans. According to some researchers, this combination of appearance and age suggests that these footprints must have come from a prehistoric man who preceded Australopithecus in evolution. But that would mean that there were pre-humans in Europe more than five million years ago.
So far, however, this scenario has been highly controversial and several alternative explanations for the human-like appearance of the footprints have been suggested. According to some scientists, a primeval ape and thus non-hominins could have left such traces, because some of the features can still be found in gorilla traces today. Other anthropologists disagree with this, pointing out some very clear differences. When interpreting the footprints of trachilos, there is another problem: Their exact age has so far been difficult to determine because the sequence of layers at the site is incomplete and the dates of fossil plankton in the deposits under the prints have an age range of 8.5 to 3.5 million years ago. Kirscher and his colleagues have therefore re-examined the stratigraphy and microfossils and re-dated the trace layer with the help of chemical, mineralogical and isotopic analyzes.
Oldest traces of a prehistoric man
The analyzes showed that the footprints of Trachilos were made around 6.05 to 6.06 million years ago. “The tracks are almost 2.5 million years older than the tracks from Laetoli in Tanzania, ascribed to Australopithecus afarensis (Lucy),” says Kirscher. In addition, the prints on Crete are about as old as the fossils of the hominin Orrorin tugenensis from Kenya. His fossils discovered in 2001, especially his thigh bones, suggest that this primeval primate may also have been walking upright and thus could have been one of the pre-forms of man. However, no footprints have survived from Orrorin. The as yet unknown primate, which left its traces in the beach sand on Crete, could therefore have left the oldest known traces of a pre-human being, as the research team explains.
If the dating of the footprints and their pre-human origins are confirmed, then this will also shed new light on the early evolution of human running over six million years ago. If you take these traces and the fossils of the 7.2 million year old Graecopithicus together, then the eastern Mediterranean, like East Africa, could have been one of the centers of human evolution. According to the team around senior author Madeleine Böhme from the University of Tübingen, climate change in the Sahara region could have led to preforms of the apes and humans moving back and forth between Africa and Eurasia. During a desertification phase 6.25 million years ago, European mammals and possibly great apes could have migrated to Africa via Mesopotamia. When the Sahara dried up, it formed a barrier and thus triggered a separate, but partially parallel development of the African pre-human Orrorin tugenensis and a European pre-human – according to the hypothesis of Böhme and her colleagues. However, there is still no clear evidence of this.
Source: Uwe Kirscher (Eberhard Karls Universität Tübingen) et al., Scientific Reports, doi: 10.1038 / s41598-021-98618-0