Malapa, South Africa
The remains of a juvenile hominid skeleton, of the new Australopithecus sediba species, are the 'most complete early human ancestor skeleton ever discovered.' (Alexander Joe/AFP/Getty Images)
During the past 50 years or so, the picture of human evolutionary history has changed dramatically. Where there used to be a straight line from one ancestor to the next are now branches snaking off every which way, with different species of upright-walking primates living at the same time, and sometimes in the same place.
The reason? Fossils. While finding fossils can answer a lot of questions, it can also raise new ones, reopening mysteries once thought to be solved.
“The sort of initial reasons why humans started walking on two legs is not well understood,” William Harcourt-Smith, a paleoanthropologist at the American Museum of Natural History and Lehman College, told Weather.com. “We’re a little bit back to the drawing board. We’re trying to work out the big why.”
Here, we take a look at some of the most ground-shaking fossil finds in the human evolution story and the places they turned up.
First up, South Africa.
Packed into the ground beneath South Africa, just outside of Johannesburg, is a trove of bones revealing a new picture of human evolution. The richness comes from the area’s geology, Harcourt-Smith said. It’s packed with limestone, a porous rock that lends itself to the formation of cavities and cave systems, into which water carrying animal remains flows, leaving the remains to solidify and fossilize over generations. When gold miners rushed the caves for the lime, needed for their mining, they opened up a world for scientists to explore. “There are just fossils everywhere,” Harcourt-Smith said. “It just happens to be that the dates of these caves are roughly the time when the human lineage is developing, which is really great.”
One such site is Malapa, 2 million years old and the locale of the discovery of Australopithecus sediba, announced about three years ago. The archeologists who made the finding uncovered remarkably complete sets of bones and proposed that A. sediba may be a transitional species between the genus Homo, to which modern humans belong, and the australopiths, which were more primitive. “It’s an unusual new find,” Harcourt-Smith said. “They’re just actually right now unearthing more material.”
NEXT: The first walker