In a discovery which will be ignored by blinkered creationists, Darwin's theories about evolution have been supported (again). Australopithecus sediba, first discovered near Johannesberg in 2010, could be the missing link with which modern humans can trace their origins back to primates, a new ancestor to homo erectus, the creature scientists believe roamed the Earth about 1 million years ago and eventually evolved into homo sapiens.
Professor Lee Berger (who famously used Google Earth to locate the caves where the remains of a male juvenile and female A. sediba were buried) has been analysing the 1.9 million year old fossilised remains since their discovery, and has now told Science Magazine that features of Australopithecus sediba's brain, hands and feet all suggest that it could be a direct evolutionary link between Australopithecus, 2 million years ago, and homo sapiens, us.
First, Berger and his team have narrowed down the age of the remains from the original estimate of between 1.77 million and 1.95 million years old. The new results indicate that A. sediba is between 1.977 and 1.98 million years old, a window of just 3,000 years which puts the remains in exactly the right timeframe to be the missing link.
The first key feature which suggests a close link between A. sediba and homo sapiens is the creature's skull cavity. An X-ray scan of the male's skull suggests an adult brain volume of around 440 cubic centimetres, or about the size of the average grapefruit. This would give A. sediba a smaller brain than some of the other candidates for the missing link, including 3.2 million year old Australopithecus afarensis. The remarkable fact is that the virtual cast created at Grenoble's European Synchrotron Radiation Facility suggests that the brain is more human-like in its shape, particularly at the front.
Australopithecus sediba has also been revealed to have a pelvis far closer to the Australopithecus afarensis, which is going some way to cast doubt on an old evolutionary theory that hip size was linked to brain size, and that our ancestors developed bigger hips in tandem with giving birth to infants with larger heads (and therefore brains).
The remains have also demonstrated that A. sediba's hands and feet are far closer to being shaped likethose of humans than primates, with the team arguing that the dexterity of the fingers could have allowed them to make simple tools. Signs of powerful grasping muscles in the hands and ape-like shin bones suggest that A. sediba spent a lot of time climbing through trees, but the fingers are proportionally much shorter than those of, for example, a chimpanzee.
Berger, from Johannesberg's University of the Witwatersrand, is convinced of his findings, telling BBC news: "Any one of these features could have evolved separately, but it is highly unlikely that all of them would have evolved together if A. sediba was not related to our lineage."
The sad truth is that no discovery of this nature is likely to convince anyone gullible enough to still believe in creationism or intelligent design. But this new vindication of Darwin's broader theories could plug a missing gap in the knowledge of how humans came to exist in their modern form. The evolution 'debate' has taken on an unpleasant tone in the last decade or so, as the language has shifted subtly to the point where rational people are now having to say that they 'believe' in evolution, adopting empirical evidence and scientific method as a faith position, when it is not.
Hopefully this new discovery, and more to come in the future, will begin to shift this attitude back towards sanity.