Dexterity of human hand backdated a half million years
|December 18, 2013||Posted by News under Human evolution, News|
To 1.42 mya
The discovery of an ancient bone at a burial site in Kenya puts the origin of human hand dexterity more than half a million years earlier than previously thought.
In all ways, the bone – a well-preserved metacarpal that connects to the middle finger – resembles that of modern man, PNAS journal reports.
It is the earliest fossilised evidence of when humans developed a strong enough grip to start using tools.
Apes lack the same anatomical features.
“This bone is the third metacarpal in the hand, which connects to the middle finger. It was discovered at the ‘Kaitio’ site in West Turkana, Kenya,” said Carol Ward, professor of pathology and anatomical sciences at MU. The discovery was made by a West Turkana Paleo Project team, led by Ward’s colleague and co-author Fredrick Manthi of the National Museums of Kenya. “What makes this bone so distinct is that the presence of a styloid process, or projection of bone, at the end that connects to the wrist. Until now, this styloid process has been found only in us, Neandertals and other archaic humans.”
Here’s what’s really interesting:
Ward said. “With this discovery, we are closing the gap on the evolutionary history of the human hand. This may not be the first appearance of the modern human hand, but we believe that it is close to the origin, given that we do not see this anatomy in any human fossils older than 1.8 million years. Our specialized, dexterous hands have been with us for most of the evolutionary history of our genus, Homo. They are – and have been for almost 1.5 million years – fundamental to our survival.”
But wait: Until now, we didn’t see this anatomy in fossils that were 1.4 million years old (“more than half a million years earlier than previously thought”), so we might find it in older fossils still. (Paper.)
When exactly does that long, slow process of evolution get to happen?
File under: When, exactly?
File with: Michael Cremo is still wrong, of course.