The hobbit: was it a work of fiction?

It is either the most important discovery in human evolution for decades, or one of the biggest blunders of modern science - and there's not much room for anything in between.

She was either a new species of miniature "Hobbit-like" human, just three feet tall, who lived 18,000 years ago on a remote Indonesian island among giant rats, pygmy elephants and massive, dragon-like reptiles. Or she was just another member of our own species - Homo sapiens - who was unfortunate enough to suffer from a severe congenital disorder that meant she developed an unusually small braincase, stunted body and shortened limbs.

If the latter is ever proved to be the case, it will come as a huge embarrassment to the scientists behind a study published in the journal Nature in 2004, claiming that Homo floresiensis truly represents a new species of miniature human being.

The latest salvo in the dispute over the bones has come in a study published in the current issue of the journal Proceedings of the National Academy of Science, which backs up claims that the "hobbit" is nothing more than a small-brained member of our own species.

The authors of the study claim that the original assessment of the remains was wrong, and that there is no evidence for the existence of a miniature species of human who hunted pygmy rats and who was in turn hunted by giant Komodo dragons.

The dispute over the bones of the "hobbit" broke out almost as soon as the details of its existence emerged in a groundbreaking piece of research that, it is fair to say, set the world of palaeo-anthropology alight.

A team of Indonesian and Australian scientists had found a partial skeleton of a creature they labelled LB1, the first human from Liang Bua cave on the island of Flores.

What was unique and utterly amazing about the individual - apparently an adult female, although the original artist's impression that accompanied the research, right, was drawn depicting a male - was that she must have lived with a skull containing a braincase no bigger than a grapefruit - about a third of the size of that of modern-day humans. She would have also stood barely three feet high.

Being this height is not in itself unusual. Some modern-day pygmies are this height, a dwarfism that results from lacking the typical adolescent growth spurt of non-pygmy humans. But the head size - and braincases - of modern pygmies still fall within the normal range of the other members of Homo sapiens.

But the "hobbit", as the female at Liang Bua cave was nicknamed, had a far smaller head that was more in proportion with her body.

Professor Mike Morwood of the University of New South Wales in Armidale, a leading member of the team, said at the time that he could not believe what he and his colleagues had found - especially given that the carbon dating pointed to the creatures still living on Flores as recently as 13,000 years ago.

"It is a new species of human who actually lived alongside us, yet were half our size. They were the height of a three-year-old child, weighed around 25 kilos [4 stones] and had a brain smaller than most chimpanzees," Professor Morwood said in 2004.

"Even so, they used fire, made sophisticated stone tools and hunted stegadon - a primitive type of elephant - and giant rats. We believe that their ancestors may have reached the island using bamboo rafts. The clear implication is that, despite tiny brains, these little humans were intelligent and almost certainly had language," Professor Morwood said.

For evolutionary biologists, the discovery pointed to the first case of endemic island dwarfism in humans. Animals isolated on a remote island can evolve into giants - like the Flores rat - or pygmies, such as the stegadon.

"Although a common feature of large mammals in insular environments, this has never been recorded for a human relative before," said Peter Brown of the University of New England, another leading member of the team.

Archaeological evidence suggests that the Liang Bua cave was inhabited by early humans of some description for about 800,000 years.

Archaeologists have also found relatively sophisticated stone tools in the cave that appear similar to those made at other sites in the world by an earlier species of human called Homo erectus. However, the crucial difference between Homo erectus tools and those at Liang Bua is that the Flores cave artifacts are far smaller - suggesting that they were honed by the tiny hands of the miniature humans.

"Finding these hominins on an isolated island in Asia, and with elements of modern human behaviour in tool-making and hunting, is truly remarkable and could not have been predicted by previous discoveries," Professor Brown said.

Within weeks of the discovery, however, doubts began to arise. The leading critic of the "hobbit theory" emerged in the form of Professor Teuku Jacob of Gadjah Mada University in Yogyakarta. A veteran Indonesian palaeo-anthropologist, Professor Jacob suggested that Homo floresiensis was not a new species at all, but merely an unfortunate, anatomically modern human with microcephaly - a disease that causes stunted growth and a small braincase. "Everything points to the direction of Homo sapiens," he said.

Professor Jacob, an influential figure in Indonesian science, infuriated the original discoverers of the hobbit by getting access to the bones through his friend and long-time colleague, Professor Radien Soejono of Indonesia's Centre for Archaeology in Jakarta, who was a co-author on the original Nature study.

There have since been claims that the bones have been damaged during the time they were in Professor Jacob's care, claims he denies.

Professor Jacob leads the list of authors in the latest paper in the Proceedings of the National Academy of Science, which also includes Professor Soejono, who now appears to have changed his mind as well as his allegiances.

The study also includes Robert Eckhardt, professor of developmental genetics and evolutionary morphology at Penn State University. "LB1 is not a normal member of a new species, but an abnormal member of our own," Professor Eckhardt said.

The thrust of the criticism is that the original researchers used a Eurocentric approach in determining whether the features of the LB1 skeleton were indeed unusual enough to warrant classification as a separate species.

"LB1 looks differently if researchers think in terms of European characteristics because it samples a population that is not European, but Australomelanesian, and further because it is a developmentally abnormal individual, being microcephalic," Professor Eckhardt said.

"To establish a new species, palaeo-anthropologists are required to document a unique complex of normal traits not found in any other species," he said. "But this was not done. The normal traits of LB1 were not unique and its unusually small braincase was not normal."

To date, scientists have amassed skeletal remains from nine individuals from the Liang Bua cave but most of these are body fragments - such as an odd tooth - rather than the partial skeleton and skull of LB1.

"What would clinch it is if we could find another skull," said Professor Richard Roberts of the University of Wollongong in Australia, one of the original discoverers.

The latest onslaught from the non-hobbit camp does not impress the team who made the find and wrote the seminal 2004 scientific paper in Nature. "There's nothing in it that's revelatory. I'm not changing my mind on the basis of what they have published," Professor Roberts said yesterday."Complete rubbish. None of their arguments stand up at all," said Professor Brown, who questioned whether the study had been properly peer-reviewed by the journal.

"There's absolutely nothing to it. We've been asking them to supply any modern skeleton that has the same features as the hobbit, and they haven't done it," he said.

Such disagreements are unlikely to be resolved for some time. Yet another study is shortly to be published in the Journal of Human Evolution which supports the idea that the LB1 skeleton of the "hobbit" does indeed belong to a new human species.

Debbie Argue and Colin Groves of the Australian National University in Canberra dismiss the idea that the individual is microcephalic and their assessment supports the contention that the "hobbit" belongs to a new species called Homo floresiensis.

"This is a completely independent study and it validates our claim that the skeleton belongs to a new human species," said Professor Brown. "It completely supports our original study and it's by a group who don't have a political axe to grind," said Professor Brown.

But even this is unlikely to be the final word on the LB1 skeleton. Another group of scientists at Stony Brook University in New York have studied it in detail and concluded that "she" may not have been female after all.

Few bones of contention are destined to be chewed over for so long as those of the hobbit.