A closer look at 1.9 million-year-old brain

It might just be a glimpse of what our ancestors' brains looked like 1.9-million years ago.

The brain, or an impression of it, was spotted in a high-definition scan conducted of the child skull of the newly discovered Australopithecus sediba.

Scientists at the European Synchrotron Radiation Facility in Grenoble, France, believe they have also found, deep in the skull cavity, fossilised insect eggs.

Last week scientists announced to the world a new species called A. sediba, which was found just outside Joburg, in the Cradle of Humankind.

Two individuals were found, a juvenile aged between nine and 13 and a woman, and some palaeoanthropologists believe that the species might be a direct ancestor of man.
"What we have got here is a possible brain impression, and it looks like shrunken brain" said Paul Tafforeau, a palaeoanthropologist at the European Synchrotron Radiation Facility.

What Tafforeau and his team did was conduct a high-quality scan of the juvenile skull, using X-rays generated by a synchrotron. They were able to get an image resolution far greater than more conventional X-ray machines.

The skull was taken to France in February, under tight security.

What caused the brain to shrink, believes Tafforeau, was mummification, which sits comfortably with the hypothesis put forward by Professor Lee Berger of Wits University and his team that the hominids, fell to their deaths down a sinkhole.

"Before fossilisation took place, the brain would have lost most of its water, causing it to shrink to a 20th of its size," explained Tafforeau. "Later, when the cadaver was immersed in water, sediment filled the brain cavity. This created a natural cast of the brain."

Tafforeau is cautious about the discovery and says further research still needs to be done.

If it proves to be the remnant of a brain, this will be the second time that this has been found in the fossil record.

The only other example of a fossilised brain was that of a 300 million-year-old fish.

But because of the shrinkage, Tafforeau believes they won't be able to find out much about the original structure of the brain.

What it would be important for, he explained, was in determining how the hominid was preserved after death.

Also providing clues to those first days after death are three insect eggs found inside the skull. The eggs could belong to a wasp and a fly. Two are open and one closed.

"What we need to establish is, are they fossilised eggs. It could be they are modern. The skull was exposed to the surface... But our preliminary examination suggests that the eggs are dense, which could mean that they are fossilised," Tafforeau said.

But it might take as long as a year for Tafforeau and the team to analyse the data and come to a conclusion.

The scan was also helpful in establishing the age of the juvenile hominid by analysing enamel build-up on the teeth.

"For the first time, what we have got here is the forensic analysis of a death of a hominid 1.9-million years ago," said Tafforeau.