Skull of Homo erectus throws story of human evolution into disarray
The odd dimensions of one of five fossils found at Dmanisi, Georgia prompted scientists to look at normal skull variation, both in modern humans and chimps, to see how they compared. They found that while the Dmanisi skulls looked different to one another, the variations were no greater than those seen among modern people and among chimps.
The scientists went on to compare the Dmanisi remains with those of supposedly different species of human ancestor that lived in Africa at the time. They concluded that the variation among them was no greater than that seen at Dmanisi. Rather than being separate species, the human ancestors found in Africa from the same period may simply be normal variants of H erectus.
Some palaeontologists see minor differences in fossils and give them labels, and that has resulted in the family tree accumulating a lot of branches.
The analysis also casts doubt on claims that a creature called Australopithecus sediba that lived in what is now South Africa around 1.9m years ago was a direct ancestor of modern humans. The species was discovered by Lee Berger at the University of Witwatersrand.