Footprint find on Crete may push back date humans walked upright

These footprints, found at Trachilos in western Crete, have been attributed to an ancient human ancestor that walked upright some 5.7 million years ago. Credit: Andrzej Boczarowski

HUMAN-like footprints have been found stamped into an ancient sea shore fossilised beneath the Mediterranean island of Crete.

Testing puts the rock’s age at 5.7 million years.

That’s a time when palaeontologists believe our human ancestors had only apelike feet.

And they lived in Africa.

But a study into the Trachilos, western Crete, prints determines them to feature prominent human features and an upright stance.

And that’s significant as the human foot has a unique shape. It combines a long sole, five short toes, no claws — and a big toe.

In comparison, the foot of a Great Ape look much more like a human hand.

And that step in evolution wasn’t believed to have taken place until some 4 million years ago.

Comparison of Trachilos footprint with bears (top), non-hominin primates (middle), and hominins (bottom). (a) Brown bear (b) Grizzly bear (c) Vervet monkey (d) Lowland gorilla (e) chimpanzee. (f) modern human (g) Trachilos footprint (h) modern human foot (i) Archaic Homo footprint. Pictures: Gerard D. Gierliński et al / Elsevier

Comparison of Trachilos footprint with bears (top), non-hominin primates (middle), and hominins (bottom). (a) Brown bear (b) Grizzly bear (c) Vervet monkey (d) Lowland gorilla (e) chimpanzee. (f) modern human (g) Trachilos footprint (h) modern human foot (i) Archaic Homo footprint. Pictures: Gerard D. Gierliński et al / ElsevierSource:Supplied

“The interpretation of these footprints is potentially controversial,” the study’s abstract admits.

“The print morphology suggests that the trackmaker was a basal member of the clade Hominini (human ancestral tree), but as Crete is some distance outside the known geographical range of pre-Pleistocene (2.5 million to 11,700 years ago) hominins we must also entertain the possibility that they represent a hitherto unknown late Miocene primate that convergently evolved human-like foot anatomy.”

Put simply, the study argues there was another — previously unidentified — human-like creature walking the Earth long before we believed it was possible.

A reconstruction of the skeleton of Australopithecus sediba, centre, next to a small-bodied modern human female, left, and a male chimpanzee. Picture: AP

A reconstruction of the skeleton of Australopithecus sediba, centre, next to a small-bodied modern human female, left, and a male chimpanzee. Picture: APSource:AP

The existing pool of evidence into humanity’s origins is built around Australopithecus fossils found in south and East Africa, along with a 3.7 million-year-old set of upright hominin (human ancestor) footprints found in Tanzania.

Called the Laetoli footprints, these are believed to have been made by Australopithecus with a narrow heel and poorly defined arch.

In contrast, a set of 4.4 million-year-old prints found in Ethiopia are believed from the hominin Ardipithecus ramidus. These prints are much closer to that of an ape than a modern human.

But the Trachilos footprints, at 5.7 million years, appear to be more human than Ardipithecus.

Maps and photos detailing the location and shape of the track-bearing stone in Crete. Pictures: Gerard D. Gierliński et al / Elsevier

Maps and photos detailing the location and shape of the track-bearing stone in Crete. Pictures: Gerard D. Gierliński et al / ElsevierSource:Supplied

They were found by the study’s lead author, Gerard Gierlinski, while he was holidaying on the island of Crete in 2002. The palaeontologist at the Polish Geological Institute has taken more than a decade to analyse his find.

The Trachilos prints have a big toe very similar to our own in size, shape and position. It has a distinct ball on its sole. It has the human-like sole. It doesn’t have claws.

They were pressed into the firm but wet sands of a small river delta at a time when the Sahara was lush and green, and savanna extended from North Africa around the Eastern Mediterranean. Crete itself was still part of the Greek mainland then.

The three most well-preserved footprints, each shown as a photo (left), laser surface scan (middle) and scan with interpretation (right). a was made by a left foot, b and c by right feet. Scale bars, 5cm. 1—5 denote digit number; ba, ball imprint; he, heel imprint. Pictures: Gerard D. Gierliński et al / Elsevier

The three most well-preserved footprints, each shown as a photo (left), laser surface scan (middle) and scan with interpretation (right). a was made by a left foot, b and c by right feet. Scale bars, 5cm. 1—5 denote digit number; ba, ball imprint; he, heel imprint. Pictures: Gerard D. Gierliński et al / ElsevierSource:Supplied

They have been dated using foraminifera (analysis of marine microfossils) as well as their position beneath a distinctive sedimentary rock layer created when the Mediterranean Sea dried up about 5.6 million years ago.

The footprints’ discovery also comes shortly after the fragmentary fossils of a 7.2 million-year-old primate Graecopithecus, discovered in Greece and Bulgaria, were reclassified as belonging to the human ancestral tree.

The path of Human evolution could be rewritten

The discovery of two apelike fossils with human-like teeth in Bulgaria and Greece could change the evolution of man from Africa to Europe.

  • May 23rd 2017
  • 3 months ago
  • /video/video.news.com.au/News/

Source

http://www.news.com.au/technology/science/evolution/footprint-find-on-crete-may-push-back-date-humans-began-to-walk-upright/news-story/2e60cbd7386573dd2a45c5cc9d79297d

Leave a Reply

Your email address will not be published. Required fields are marked *

*