TÜBINGEN, Germany — Fossilized footprints on the Greek island of Crete are giving scientists a fascinating look at how the human foot evolved — six million years ago! The prints, discovered in fossilized beach sediments near the village of Trachilos in 2017, are more than two million years older than those left behind by the famous female hominid named “Lucy,” found in Africa in 1974.
An international research team estimate that the Trachilos prints date back 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 Australopithecus afarensis — Lucy — from Laetoli in Tanzania,” says study co-leader Dr. Uwe Kirscher of Tübingen University in a release.
He notes that the findings put the Trachilos footprints at the same age of the upright-walking Orrorin tugenensis from Kenya. Previous discoveries involving fossils from this biped include leg bones like the femur, but no foot bones or footprints. Dr. Kirscher explains that the dating of the Cretan footprints sheds new light on the early evolution of human movement during prehistoric times.
“The oldest human foot used for upright walking had a ball, with a strong parallel big toe, and successively shorter side toes. The foot had a shorter sole than Australopithecus. An arch was not yet pronounced and the heel was narrower,” says study co-author Per Ahlberg, a professor at Uppsala University in Sweden.
How did early humans get to this island?
Scientists believe the island of Crete was still part of the Greek mainland via the Peloponnese region six million years ago.
“We cannot rule out a connection between the producer of the tracks and the possible pre-human Graecopithecus freybergi,” notes study co-leader Professor Madelaine Böhme, also of the University of Tübingen.
Prof. Böhme’s team identified that previously unknown pre-human species several years ago, in what is now Europe. The discovery came from an analysis of fossils in 7.2 million-year-old deposits in Athens, just over 150 miles away.
The new study confirms recent research and theories of Prof. Böhme’s team, which believe that six million years ago the European and Near East mainland were separated from humid East Africa by a relatively brief expansion of the Sahara. Geochemical analysis of Crete’s six million-year-old beach deposits suggests that winds transported desert dust from North Africa.
The team arrived at an age of between 500 and 900 million years before the present when dating dust-sized mineral grains. The time periods are typical for North African desert dust, according to the researchers.
Rewriting the human family tree
Prof. Böhme adds recent studies also suggest that the African ape Sahelanthropus was not a biped and that Orrorin tugenensis, which originated in Kenya and lived 5.8 to 6.1 million years ago, is the oldest pre-human in Africa. Short-term desertification and the geographic distribution of early human predecessors could therefore be more closely related than previously thought.
“On the one hand, a desertification phase 6.25 million years ago in Mesopotamia could have initiated a migration of European mammals, possibly including apes, to Africa. On the other hand, the second-phase sealing off of the continents by the Sahara six million years ago could have enabled a separate development of the African pre-human Orrorin tugenensis in parallel with a European pre-human,” Prof. Böhme concludes.
According to that principle, dubbed “desert swing” by Prof. Böhme, successive short-term desertification in Mesopotamia and the Sahara caused a migration of mammals from Eurasia to Africa.
The findings appear in the journal Scientific Reports.
South West News Service writer Stephen Beech contributed to this report.