Bone discovery pushes back oldest “modern” hand to 1.85 million years

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Discovery of a new pinkie bone from Africa has effectively pushed back the date of the oldest ‘modern’ hand suggesting that key step in the evolution of our ancestors from tree-climbing foragers to tool-wielding hunters happened earlier than previously believed.

Found from Olduvai Gorge in Tanzania, the 3.6-centimetre (1.5-inch) little finger bone reveals a lot about body type and behaviour during those days, researchers suggest.

Lead author Manuel Dominguez-Rodrigo, a researcher at the Institute of Evolution in Africa in Madrid explained that not only is the shape of the bone a reflection of the evolution at the time, it also is a driver of that evolution.

According to researchers the transition of our ancestors happened in two stages. First stage was some six million years ago when all members of the Homo genus began walking on two legs. Their thumbs got longer, but there was no impact on the shape of the curved fingers indicating that though our forebears started walking, they did go about climbing trees.

Then came the second stage after some 4 million years ago, when they abandoned their arboral perches because of which their fingers began to straighten.

Because they didn’t require the use of arms to climb trees, their hands were free and were only required in manipulative capacity.

“Hands were freed from locomotion in trees so that they could become strictly specialised in manipulation,” said Dominguez-Rodrigo in an emailed statement. “This is where our discovery fills a gap.”

“Our discovery not only shows that a creature”—dubbed OH 86—”with a modern-looking hand existed 1.85 million years ago, it also shows that OH 86 was bigger sized than any other prior and contemporary hominin,” said Dominguez-Rodrigo.

The latest discovery effectively pushes the earliest ‘modern’ hand back by around 400,000 years.