‘Hobbits’ and humans took different evolutionary paths
Researchers who have studied the bones of Homo floresiensis, a species of tiny human discovered on the Indonesian island of Flores in 2003, say their findings should end a popular theory that it evolved from an ancestor of modern humans.
The study, led by Australian National University researcher Dr Debbie Argue from the school of archaeology and anthropology, found there was no evidence that the diminutive 1.1-metre-tall Homo floresiensis evolved from the much larger Homo erectus, the only other early hominid known to have lived in the region.
It was one of several theories about the origins of the ‘‘hobbit’’ species. Since it was discovered, researchers have tried to determine whether Homo floresiensis was a species distinct from humans.
A member of the research team, Professor Colin Groves, said the theory of a link with the Asian Homo erectus, the first of our relatives to have modern human proportions, was ‘‘a good scientific hypothesis’’.
‘‘But we believe it has now been thoroughly refuted,’’ he said.
Groves said the researchers had gone into the study of the species with an open mind. But their findings supported another popular theory: that Homo floresiensis was in fact far more primitive than Homo erectus and had characteristics more similar to Homo habilis, which lived between 1.65 million and 2.4 million years ago, and which is the most ancient representative of the human genus.
The researchers collected 133 cranial, postcranial, mandibular and dental samples from a variety of ancient and more modern species for analysis and comparison, travelling to several countries, including in Africa and Europe. The number of samples collected was more comprehensive and ambitious than had been carried out before. Most previous studies of the species examined only the skull and lower jaw.
The researchers also used modern methods of statistical analysis based on the latest evidence.
Homo erectus and Homo floresiensis were found to have completely different bone structures, particularly in the jaw and pelvis.
‘‘A close relationship between Homo erectus and Homo floresiensis is rejected, which contradicts the proposal that island dwarfing of Asian Homo erectus led to Homo floresiensis,’’ the study, published in the Journal of Human Evolution, concludes.
The findings add support to the theory that the species evolved from one in Africa, most likely Homo habilis, and that the two species shared a common ancestor. The researchers concluded that it was possible that Homo floresiensis evolved in Africa and migrated, or that the common ancestor moved from Africa and then evolved into Homo floresiensis somewhere else.
Professor Mike Lee of Flinders University and the South Australian Museum used statistical modelling to analyse the data collected by the researchers. He said the findings were clear.
‘‘Homo floresiensis occupied a very primitive position on the human evolutionary tree,’’ Lee said. ‘‘We can be 99 per cent sure it’s not related to Homo erectus, and nearly 100 per cent it isn’t a malformed Homo sapiens.’’