Evrim Yazgin
Cosmos science journalist
Hands capable of using tools might have evolved much earlier than previously thought according to a new study of Australopithecus finger bones.
The researchers analysed muscle attachment sites on the fossilised hands of 3 species of Australopithecus: A. afarensis (lived 3.9–2.9 million years ago), A. africanus (3.3–2.1 million years ago) and A. sediba (about 1.98 million years ago).
These results were then compared to the hands of ancient and modern primates including modern humans, Neanderthal, gorilla, chimpanzee and orangutan.
Findings of the study are published in the Journal of Human Evolution.
Three-dimensional models of the hand bones allowed the researchers to benchmark human- versus ape-like hands.
Muscle attachment areas on the fossil hands were determined based on differences in bone surface elevation, colouration and surface texture.
The results reveal that A. sediba and A. afarensis (most famously represented by the 3.2-million-year-old skeleton named “Lucy”) possessed an anatomy which would allow them to manipulate objects in a similar way to modern humans.
A. africanus, meanwhile, had a mixture of attachment features both human- and ape-like hand use.
It perhaps isn’t a surprise that early hominins were capable of using tools. Chimpanzees – which split from humans evolutionarily about 6 million years ago – are known to use stones and sticks as tools in the wild.
But the new study sheds light on just how advanced our early ancestors were in their ability to use tools.
“The frequent activation of muscles needed to perform characteristic humanlike grasping and manipulation in these early hominins lends support to the notion that humanlike hand use emerged prior to, and likely influenced, the evolutionary adaptations for higher manual dexterity in later hominins,” the researchers write.
The oldest stone tools found date to about 3.3 million years ago. Even earlier evidence of cut marks on mammal bones indicates tools were used to render meat.
But the makers and users of these early stone tools remains a mystery.
