Hobbit may be new species

Researchers have added new weight to theories that a "hobbit" found by Australian scientists in Indonesia is related to a unknown human species.

Bones belonging to a mini-human and believed to be about 18,000 years old were unearthed on the Indonesian island of Flores in 2004, sparking theories about her ancient relatives.

Since then, scientists have debated whether Homo floresiensis – or Lucy as she has been nicknamed – was a descendant of a known human species, suffered from some sort of genetic disease which caused her to be so small or belonged to a new species.

A new study of her bones by American scientists William Jungers and Karen Baab has given fresh impetus to the theory that Lucy is a genuine ancient human species and not a descendant of healthy humans dwarfed by disease.

Their study, published in the December issue of Britain's Royal Statistical Society magazine Significance, was based on a detailed examination of Lucy's skull and other bones which led them to estimate her weight and height.

Their analysis suggests it was unlikely that she was a relative of Homo erectus or other known human species and was instead "probably derived instead from an even more primitive hominin species".

They found her brain was "remarkably small" compared to living humans, including modern pygmies, and more similar to those of chimpanzees and ancient hominins like the bipedal "ape men" of Africa.

While some scientists have argued Lucy's head was unusually small because she suffered from a disease, Dr Jungers and Dr Baab found no resemblance between her brain shape and that of modern humans with abnormally small heads.

They suggested Lucy was not a dwarfed descendant of Homo erectus but a different species "with already-small bodies and smaller brains when they arrived on Flores".

Dr Jungers and Dr Baab also reconstructed Lucy's body shape and size and found it to be unlike any modern human because of its shorter thigh and shin bones.

They estimated she was much smaller and stockier in shape to modern humans, even when compared to the smallest living people.

She was just 106cm tall and weighed 30-35kg, suggesting a "very non-human body shape for our hobbit, in the sense that a relatively large mass is being distributed over a relatively small skeletal frame".

"This is not a pygmy human," Dr Jungers, who works closely with the Australian scientists who discovered Lucy, told AAP.

The Australian Research Council is providing funding for a five-year project so Dr Jungers and Australian scientists can continue their work on trying to establish Lucy's ancestors.

Dr Jungers said the team would return to Indonesia to examine sites near to where Lucy was found and where tools dating back one millions years have been unearthed.

"We will focus on finding skeletons that go with the tools," he said.

"If we dig up bones of H erectus, the diseased dwarf theory will gain credibility.

"But if there are bones like Lucy's or H habilis, our hypothesis that this is a more primitive human than H erectus will gain more support."

- AAP