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A chimpanzee and a human hold hands at an ape sanctuary in Brazil. New research suggests australopithecines' hands had a mix of ape and human traits. Lucy and her fellow australopithecines may have created and used tools more than 3 million years ago, a new study of hand muscles suggests.
The finding provides further evidence that tool use started long before the Homo genus emerged. "While we can't definitively say that these early humans crafted stone tools, our findings demonstrate that their hands were frequently used in ways that closely align with the actions necessary for human tool manipulation," study co-author Fotios Alexandros Karakostis , a paleoanthropologist at the University of Tùˆbingen in Germany, told Live Science in an email. In a study published in the November issue of the Journal of Human Evolution , researchers examined muscle attachment sites on the hand bones of three australopithecine species and compared them with ape and human hands to try to understand when our ancestors gained the dexterity that modern humans have.
Since australopithecines represent the chronological mid-point in the evolution of humans from ancient apes, the researchers suspected that australopithecine hand bones may also have traits of both apes and humans. The researchers focused on hand entheses, which are places where tendons attach muscles to bones. When muscles and joints are used frequently, these attachment sites adapt, resulting in a pattern of bony changes that suggest specific habitual activities.
"By studying these muscle attachment sites, we can reconstruct how muscles and ligaments were actively engaged throughout life, giving us a clearer picture of early hominin behavior," Karakostis said. Related: Our mixed-up human family: 8 human relatives that..
. Kristina Killgrove.
