"Ancient Hominin or Mystery Primate?" --5.7 Million Year Old 'Unmistakably Human' Footprints Discovered
In a discovery that could challenge accepted theories of human evolution, researchers found 5.7 million years old unmistakably human-like footprints laid down in what is now Crete, that could belong to a previously unknown primate, and perhaps even an ancient hominin — an animal more closely related to humans than to chimps. The finding could take the trail of early human evolution beyond Africa. Earlier studies had suggested that all fossil hominins older than 1.8 million years (the age of early Homo fossils from Georgia) came from Africa, leading most researchers to conclude that this was where the group evolved.
At approximately 5.7 million years, they are younger than the oldest known fossil hominin, Sahelanthropus from Chad, and contemporary of Orrorin from Kenya, but more than a million years older than Ardipithecus ramidus from Ethiopia, the oldest hominin known from reasonably complete fossils which has an ape-like foot.
The researchers who described Ardipithecus argued that it is a direct ancestor of later hominins, implying that a human-like foot had not yet evolved at that time. This conflicts with the hypothesis that Ardipithecus is a direct ancestor of later hominins.
But the new footprints from Trachilos have a big toe similar to our own in shape, size and position. It is also associated with a distinct ‘ball’ on the sole, which is missing in apes.
The Trachilos footprints were securely dated using a combination of marine microfossils, plus the fact that they lay just below a very distinctive sedimentary rock formed when the Mediterranean Sea briefly dried out, 5.6 million years ago, during a period known as the late Miocene, when the Sahara Desert did not exist and savannah-like environments extended from North Africa up around the eastern Mediterranean and Crete had not yet detached from the Greek mainland.
Image credit top of page: With thanks to Bob Wilder at University at Buffalo
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