A 1.42 million years old bone sheds more light on how human hands evolved to hold tools, according to a University of Arkansas press release.
Over the years, the human hand has evolved and "specialized" to hold tools. As human bones are difficult to come across, scientists know very little about when and how this evolution began. A newly discovered 1.42 million years old bone will hopefully shed more light on this matter. Researchers found that human hands developed this tool-holding distinctive feature half a million years earlier than previously believed.
"With this discovery, we have the earliest evidence of the structural changes of the hand that are associated with tool use," J. Michael Plavcan, professor of anthropology at the University of Arkansas said in the news release.
The bone was discovered by Fredrick Kyalo Manthi of the National Museums of Kenya at the Kaitio site in Kenya. On analyzing it, researchers found a styloid process in the third metacarpal bone. This is a curved projection at the end of the bone that is important for hands that use tools with both dexterity and precision. This curved projection locks itself with other wrist bones, aiding the hand to resist the force and pressure created while using tools.
What makes the discovery all the more intriguing is that though evidence of the existence of stone tools date back to 2.58 million years, structural evolution of human hands to use these tools dates back to only 800,000 years.
"The newly discovered bone suggests that an increased reliance on manipulatory behaviors indicated by the archeological record early in the Pleistocene selected for the modern human hand early in the evolution of the genus Homo," the researchers wrote. There's still a huge gap in our understanding of the evolution of the hand. We need to find even earlier bones to determine just when structural features of the hand appeared."
