Fossil discovery - new piece in the puzzle

Melanie Gosling

A prehistoric human skull from the Eastern Cape has provided a vital "missing link" in the fossil record which shows that modern people originally came from sub-Saharan Africa and migrated to colonise Europe and Asia around 30 000 to 40 000 years ago.

The 36 000-year-old Hofmeyr skull, named after the Karoo town where it was found, shows that people living in Africa at that time looked the same as people living in Europe then.

This critical piece of evidence, which is published in the journal Science on Friday, corroborates genetic evidence about the African origins of modern humans. It is the first fossil evidence to support the "out of Africa" theory, which holds that all modern humans evolved in Africa and then migrated to Europe and Asia.

Alan Morris of UCT's department of human biology, was part of an international team, led by Frederick Grine of Stony Brook University in New York, that studied the skull.

'The skull is probably male and is completely modern' "The skull is probably male and is completely modern. If he sat down next to you on the Sea Point bus you would not react, apart from wondering where he came from. He would not look like modern Africans or like modern Europeans, or like modern Khoisan people, but he is definitely a modern human being," Morris said.

The skull was found decades ago, but was dated only recently. It was found in an erosion gulley in the mid-1950s near Hofmeyr, 70km north-east of Cradock.

Morris, who first saw the skull in the Port Elizabeth Museum in the 1990s, showed it to Grine a couple of years ago. Grine had it dated by a method developed by Richard Bailey of Oxford University.

Grine said in a statement that the field of anthropology was known for its hotly contested debates. One which had raged for years concerned the evolutionary origin of modern people. A number of genetic studies of living people indicated that modern humans had evolved in Africa and moved to Europe and Asia between 65 000 and 25 000 years ago to colonise these continents.

But he said other DNA tests argued against this Africa origin and exodus model.

DNA tests argued against this Africa origin and exodus model "Instead they suggested that archaic, non-African people, such as the Neanderthals of Europe, made significant contributions to the genomes of modern humans in Europe and Asia. Until now, the lack of fossil evidence from sub-Saharan Africa has meant that two competing genetic models of human evolution could not be tested by palaeontological evidence. The skull from Hofmeyr has changed that," he said.

Once the skull had been dated in Oxford, it was studied by other members of the team at the Max Planck Institute in Germany. The scientists there had expected the Hofmeyr skull to have close resemblances to the Khoisan, because they are represented in the recent archaeological record in South Africa.

Instead, the Hofmeyr fossil was found to have a very close affinity with the fossil skulls of Europeans of the Upper Palaeolithic, and is quite distinct from Khoisan specimens.

Grine said the evidence from the Hofmeyr skull agreed with the "out of Africa" genetic theory, which predicted that humans similar to those who lived in Europe and Asia around 36 000 years ago, would also be found in sub-Saharan Africa during the same period.

The Hofmeyr skull from the Karoo provides the first fossil evidence to support this prediction. - Cape Times


February 2007