Scientists in South Africa believe that a set of 2-million-year-old fossilized skeletons of could be the “missing link” in the process of evolution that led to human beings. These findings are now being called a potential game-changer.
The two fossils in question, an adult female and a juvenile male, named Australopithecus sediba (Au. sediba) were discovered in the Malapa cave system near Johannesburg, South Africa, in 2008. Both are about 1.2 meters tall, unusually complete and well preserved, and date from 1,977,000 years ago.
Until now, the Homo habilis or Homo rudolfensis were believed to be the likely ancestors of H. erectus. However, they post-dated Au. sediba by several thousand years. Professor Lee Berger of the University of Witwatersrand in South Africa led the team that found Au. sediba.Together with a large team of researchers, he spent the last year intensively studying the two fossils. Aside from the two skulls reported last year, Dr. Berger’s co-researchers also retrieved an almost complete right hand, a foot and a pelvis.
Upon analyzing the x-ray of the skull, they found out that although it was only slightly larger than a chimpanzee’s brain, it was actually human-like in appearance. The adult female’s hands and feet showed a distinct mix of modern and primitive features. Dr. Berger described the skeletons: “The fossils demonstrate a surprisingly advanced small brain, a very evolved hand with a long thumb like humans, a very modern pelvis, but a foot and ankle shape never seen in any hominin species that combine features of both apes and humans in one anatomical package.”
Texas Anthropologist Professor Darryl de Ruiter remarked, “We examined the remains and found several distinct individuals — possibly representing a family group. They all seemed to have died suddenly in the same event about 1.9 million years ago, but the remains are in surprisingly good shape.”
Australopithecines were early hominids (ape-like creatures) that lived between 4 and 2 million years ago. Unlike chimpanzees and other apes, they walked on two legs, but their brains are still small, and they still have not forsaken the trees. It was only when Homo erectus appeared 1.8 million years ago that larger brains appeared.
Professor de Ruiter also said, “It’s a great find because it provides strong confirmation for Darwin’s theories about evolution.”
The bones are especially well-preserved because their owners apparently fell into a deep cave and were swept into a sediment a few weeks later. That quickly fossilized their bones. The rocks above the cave gradually eroded away and brought the fossils to the surface. Dr. Berger’s 9-year-old son, Matthew, found one while he was chasing his dog.
“This is really exciting new material,” said Ian Tattersall, a paleoanthropologist at the American Museum of Natural History in New York. “I think it holds the possibility of flinging wide open the question of what Homo is.”
If Dr. Berger’s claim is accepted, it would radically redraw the present version of the whole human family tree. Homo habilis would be dislodged and the Au. sediba would be placed at the center as the most likely bridge between the australopithecines and the human lineage.
Several other paleoanthropologists disagree with that interpretation, but they say that the fossils are indeed very important because they shed a clear light to the mix-and-match process by which human evolution was shaped.