On the Mediterranean island of Crete have been discovered the oldest known footprints of prehistoric men, which are at least six million years old, reports an international team of researchers from Germany, Sweden, Greece, Egypt and England, led by scientists from Tübingen Uwe Kirscher and Madeline Boehme from the Senckenberg Center for Human Evolution and Paleoecology at Tübingen University. Their study was published in the journal Scientific Reports.
Footprints on fossilized beach sediments were found near the West Cretan village of Trahilos. Using geophysical and micropaleontological methods, researchers have now dated them 6.05 million years to the present day, making them the oldest direct evidence that a humanoid foot was used for walking.
“These footprints are almost 2.5 million years older than footprints attributed to Australopithecus afarensis (Lucy) from Laetoli in Tanzania,” says Uwe Kirscher. This puts the Trachilos traces in the same age as the fossils of the upright walking Orrorin tugenensis from Kenya.”
The dating of the Cretan prints thus sheds new light on the early evolution of human movement more than six million years ago.
“The oldest human foot, used for upright walking, was ball-shaped, with a strong parallel thumb and successively shortened lateral toes,” explains Per Alberg, professor at Uppsala University and co-author of the study. “The foot had a shorter sole than in Australopithecus. The vault was not yet pronounced, and the heel was narrower.”
Six million years ago Crete was connected to the Greek mainland via the Peloponnese. According to Professor Madeline Böhme, “we cannot rule out a connection between whoever left the footprints and a possible prehuman species, Graecopithecus freybergi.”
A few years ago, Boehme’s team identified this previously unknown prehuman species in present-day Europe based on fossils from 7.2 million-year-old deposits at Athens, just 250 kilometers away.
The study also confirms recent research and the Böhme team’s thesis that six million years ago the continents of Europe and the Middle East were separated from wet East Africa by a relatively brief extension of the Sahara.
Geochemical analysis of six-million-year-old beach deposits from Crete suggests that desert dust from North Africa was transported there by the wind. Dating the mineral grains the size of the dust, the team came up with ages ranging from 500 to 900 million years to the present. According to the authors, these time periods are typical of North African desert dust.
Recent studies in paleoanthropology have also shown that the African ape Sahelanthropus can be ruled out as bipedal, and that Orrorin tugenensis, which inhabited Kenya 6.1-5.8 million years ago, is the oldest prehuman in Africa, Boehme says.
Therefore, short-term desertification and the geographic distribution of early human precursors may be more closely related than previously thought.
On the one hand, the desertification phase 6.25 million years ago in Mesopotamia may have initiated the migration of European mammals, possibly including apes, to Africa. On the other hand, the second phase of continental fencing off by the Sahara 6 million years ago may have allowed the African prehuman Orrorin tugenensis to evolve in parallel with the European prehuman.
According to this principle, called “desert swings” by Böhme, successive short-term desertifications in Mesopotamia and the Sahara caused the migration of mammals from Eurasia to Africa.