Our hands and wrists are extremely complex. Dozens of tiny bones, tendons, and muscles allow us to hit, grab, smash, twist, and make hundreds of different movements. Now, a metacarpal bone found in Kaitio, Kenya, dating back about 1.42 million years ago has provided new clues about how humans came to have such a complex and evolved structure.
The shortage of continuous fossil remains has prevented researchers from knowing when our hand became a unique structure, a complex gear formed by the wrist, the hand and the fingers. Until now, thanks to the remains found in the Sima de los Huesos and the Gran Dolina , 400,000 and 800,000 years old, it was known that the hands of these ancient settlers already had hands very similar to those of today. In fact, the researchers intuited that these similarities could go back much further back in time.
This new bone found in Kenya dates back more than 1.4 million years and advances the development of the styloid process of the hand by more than 600,000 years. This process is, basically, a rearrangement of the wrist that allowed to perform more and better tasks with the hands thanks to the stabilization and locking of the joint. As Carol Ward, Professor of Pathology and Anatomical Sciences at the University of Missouri, explains, “what makes this bone so special is the presence of a styloid process or projection of the bones at the end that connects to The wrist. Until now, this styloid process has only been found in us, Neanderthals and other early hominids . “
This paleontological finding, recently published in the Proceedings of the National Academy of Sciences, PNAS, is led by a team of researchers from the University of Missouri, in the United States.
