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Fossilized footprints found near Crete may seriously complicate our ancestors’ origins

Your foot may ache, smell and maybe need a toenail trim, but it’s a pretty special bit of anatomy. Even if you’re used to your single row of clawless of toes, it’s actually a unique arrangement among just about every animal on Earth. Our closest living relatives don’t have their hallux, or big toe, facing forward like we do, giving them a much more hand-shaped foot. These toes, along with the ball of our foot and long instep, come together to make a very distinct footprint. What’s exciting scientists now is that some of these prints have turned up in a time and place where they supposedly had no business being.

A set of footprints were found hardened into sedimentary rock on an island called Trachilos, off the coast of Crete. Based on the foraminifera, or marine microfossils, found in the layers of rock above and below the slab of stone in question, researchers confidently dated the prints as being 5.6 million years old. The catch is that at that time, no human ancestors, much less humans, were thought to be anywhere but Africa. What’s more, the shape of the prints look more like modern feet than any known ancestor living at that time.

Figuring out the who, what and where

Even without an actual bone or tool, these footprints may be enough to up-end our timeline for human evolution. The oldest confirmed hominid is Ardipithecus ramidus, who is thought to be a direct ancestor to modern humans. However, A. ramidus lived in Ethiopia around 4.4 million years ago, and at that point had a much more gorilla-shaped foot. We know that by 3.65 millions ago, our ancestor Australopithecus was leaving very modern-looking footprints in Tanzania, but neither of these dates sync up with the stroll some primate took through Crete at least a million years earlier.

Putting the evolutionary questions about foot-shapes aside, walking to the island of Trachilos is actually one of the easier issues to understand. North Africa and the Mediterrean Sea were very different places 5.6 million years ago, as the Sahara Desert was a savannah and the Mediterrean was beginning to dry up, thanks to the Strait of Gibraltar closing off the waters of the Atlantic Ocean. What’s more, Crete itself was still attached to the Greek mainland, making access to this particular plot of land all the more plausible.

Many questions to consider

Assuming this initial interpretation of these 50 footprints hold up, anthropologists have a lot of new questions to explore. Were the prints made by a hominid, or just a very similar gorilla living in Europe? Did this mystery primate walk out of Africa to Trachilos, having evolved our unique feet earlier than anyone thought? Were these prints left by a direct relative to modern Homo sapiens, or is this an offshoot of our family tree that didn’t end up succeeding with their early upright gait? Or, most radically, did our ancestors originate outside of Africa, strolling south instead of north? That last idea is a long-shot, and would still leave the species Homo sapiens as originating in Africa, but this simple stroll in the soft soil now demands that we investigate a lot of new possibilities.

My third grader said: I hope it turns out to be one of the crazier explanations!

Source: What Made These Footprints 5.7 Million Years Ago? by Gemma Tarlach, Dead Things

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