“The anatomies we are seeing in Australopithecus sediba are forcing us to reassess the pathway by which we became human.”
In 2008, two partial skeletons were discovered at the fossil site of Malapa in South Africa – the site better known as the Cradle of Humankind for containing a large number of some of the oldest hominin fossils ever found. After ten years of careful study, a new report announces that not only are the two skeletons of the same hominin species, that species is highly likely to be the proverbial ‘missing link’ – the transitional species that became the first humans. If it’s true, that transition occurred much later in history than previously thought.
“The first fossil of Au. Sediba was discovered by Matthew Berger, then a nine-year-old, who happened to stop and examine the rock he tripped over while following his dog Tau away from the Malapa pit.”
The study, published in a special edition of Paleoanthropology, begins with the accidental discovery of the remains that would make a great opening scene for the movie. After that, anthropologists and co-authors Scott Williams, Jeremy DeSilva and Darryl De Ruiter dig into what Berger and his dog dug up – partial skeletons that are far more complete than ‘Lucy’, the 3.2 million-year-old Australopithecus afarensis skeleton discovered in Ethiopia in 1974.
After dating them to between 1.95 and 1.78 million years ago, the researchers studied their most missing-linkish traits – hands and feet that clearly indicated Australopithecus (which means “southern ape”) sediba were very adept tree climbers. Along with short foot bones not suitable for walking and a small brain, these showed Au. sediba was similar to Lucy. However, their hands had long opposable thumbs suitable for using tools and their teeth showed a more advanced diet than little Lucy consumed. Those traits put them closer to Homo habilis (“handy man”), the prehistoric, walking tool-user discovered in Tanzania who lived between 2.1 and 1.5 million years ago.
“Our findings challenge a traditional, linear view of evolution. It was once thought that a fossil species a million years younger than Lucy would surely look more human-like. For some anatomies of Australopithecus sediba, like the knee, that is true. But, for others, like the foot, it is not. Instead, what we’re witnessing here are parallel lineages, illustrating how different hominin experiments were unfolding early in our complex evolutionary history.”
Is the missing link no longer missing? This extensive study – nine papers by leading anthropologists, each one focusing on a single body part of Au. sediba – seems to indicate that, while this is definitely a ‘found’ missing link, there are more yet to be discovered. Like its name, the theory of evolution is destined to keep evolving.
One more thing. The origin story of the Au. sediba mentions the name of the boy AND his pet dog. Isn’t it time we make our ground-sniffing, bone-digging canine assistants honorary anthropologists?