Mystery 'Hobbits' not Human, Study Says

Diminutive humans that died out on an Indonesian island some 15,000 years ago were not Homo sapiens, but a different species, according to a study published Monday that dives into a fierce anthropological debate.

Fossils of Homo floresiensis - dubbed "the hobbits" due to their tiny stature - were discovered on the island of Flores in 2003.

Controversy has raged ever since as to whether they are an unknown branch of early humans or specimens of modern man deformed by disease.

The new study, based on an analysis of the skull bones, shows once and for all that the pint-sized people were not Homo sapiens, according to the researchers.

Until now, academic studies have pointing in one direction or another - and scientific discourse has sometimes tipped over into acrimony.

One school of thought holds that so-called Flores Man descended from the larger Homo erectus and became smaller over hundreds of generations.

The proposed process for this is called "insular dwarfing" - animals, after migrating across land bridges during periods of low sea level, wind up marooned on islands as oceans rise and their size progressively diminishes if the supply of food declines.

An adult hobbit stood a metre (three feet) tall, and weighed about 25 kilos (55 pounds).

Similarly, Flores Island was also home to a miniature race of extinct, elephant-like creatures called Stegodon.

But other researchers argue that H. floresiensis was in fact a modern human whose tiny size and small brain - no bigger than a grapefruit - was caused by a genetic disorder.

One suspect was dwarf cretinism, sometimes brought on by a lack of iodine. Another potential culprit was microcephaly, which shrivels not just the brain and its boney envelope.

Weighing in with a new approach, published in the Journal of Human Evolution, a pair of scientists in France used high-tech tools to re-examine the layers of the "hobbit" skull.

More precisely, they looked at the remains of Liang Bua 1 (nicknamed LB1), whose cranium is the most intact of nine known specimens.

Mystery solved?

"So far, we have been basing our conclusions on images where you don't really see very much," said lead author Antoine Balzeau, a scientist at France's Natural History Museum.

Joining forces with Philippe Charlier, a palaeopathologist at Paris-Descartes University specialized in solving ancient medical mysteries, the researchers secured high-resolution images recently generated in Japan to compute maps of bone thickness variation.

"There is a lot of information contained in bone layers of the skull," Balzeau told AFP.

The results, he said, were unambiguous: "There were no characteristics from our species" - that is, Homo sapiens.

And while they found evidence of minor maladies, there was nothing corresponding to the major genetic diseases other researchers had pointed to.

But if one part of the mystery may be solved, another remains intact.

For while the scientists could not exclude the possibility that the "hobbit" was a scaled-down version of Homo erectus that arrived on the neighboring island of Java some million years ago, nor could they be sure that H. floresiensis was not a species it its own right.

"For the moment, we can't say one way or the other," Balzeau said.

In this depiction, so-called hobbit humans inhabit the lush world of a small island.

Back in the Beginning

To put a human face on our ancestors, scientists from the Senckenberg Research Institute used sophisticated methods to form 27 model heads based on tiny bone fragments, teeth and skulls collected from across the globe. The heads are on display for the first time together at the Senckenberg Natural History Museum in Frankfurt, Germany. This model is Sahelanthropus tchadensis, also nicknamed "Toumai," who lived 6.8 million years ago. Parts of its jaw bone and teeth were found nine years ago in the Djurab desert in Chad. It's one of the oldest hominid specimens ever found.

Australopithecus afarensis

With each new discovery, paleoanthropologists have to rewrite the origins of man's ancestors, adding on new branches and tracking when species split. This model was fashioned from pieces of a skull and jaw found among the remains of 17 pre-humans (nine adults, three adolescents and five children) which were discovered in the Afar Region of Ethiopia in 1975. The ape-man species, Australopithecus afarensis, is believed to have lived 3.2 million years ago. Several more bones from this species have been found in Ethiopia, including the famed "Lucy," a nearly complete A. afarensis skeleton found in Hadar.

Australopithecus africanus

Meet "Mrs. Ples," the popular nickname for the most complete skull of an Australopithecus africanus, unearthed in Sterkfontein, South Africa in 1947. It is believed she lived 2.5 million years ago (although the sex of the fossil is not entirely certain). Crystals found on her skull suggest that she died after falling into a chalk pit, which was later filled with sediment. A. africanus has long puzzled scientists because of its massive jaws and teeth, but they now believe the species' skull design was optimal for cracking nuts and seeds.

Paranthropus aethiopicus

The skull of this male adult was found on the western shore of Lake Turkana in Kenya in 1985. The shape of the mouth indicates that he had a strong bite and could chew plants. He is believed to have lived in 2.5 million years ago and is classified as Paranthropus aethiopicus. Much is still unknown about this species because so few reamins of P. aethiopicus have been found.

Paranthropus boisei

Researchers shaped this skull of "Zinj," found in 1959. The adult male lived 1.8 million years ago in the Olduvai Gorge of Tanzania. His scientific name is Paranthropus boisei, though he was originally called Zinjanthropus boisei -- hence the nickname. First discovered by anthropologist Mary Leakey, the well-preserved cranium has a small brain cavity. He would have eaten seeds, plants and roots which he probably dug with sticks or bones.

Homo rudolfensis

This model of a sub-human species -- Homo rudolfensis -- was made from bone fragments found in Koobi Fora, Kenya, in 1972. The adult male is believed to have lived about 1.8 million years ago. He used stone tools and ate meat and plants. H. Rudolfensis' distinctive features include a flatter, broader face and broader postcanine teeth, with more complex crowns and roots. He is also recognized as having a larger cranium than his contemporaries.

Homo ergaster

The almost perfectly preserved skeleton of the "Turkana Boy" is one of the most spectacular discoveries in paleoanthropology. Judging from his anatomy, scientists believe this Homo ergaster was a tall youth about 13 to 15 years old. According to research, the boy died beside a shallow river delta, where he was covered by alluvial sediments. Comparing the shape of the skull and teeth, H. ergaster had a similiar head structure to the Asian Homo erectus.

Homo heidelbergensis

This adult male, Homo heidelbergensis, was discovered in in Sima de los Huesos, Spain in 1993. Judging by the skull and cranium, scientists believe he probably died from a massive infection that caused a facial deformation. The model, shown here, does not include the deformity. This species is believed to be an ancestor of Neanderthals, as seen in the shape of his face. "Miquelon," the nickname of "Atapuerca 5", lived about 500,000 to 350,000 years ago and fossils of this species have been found in Italy, France and Greece.

Homo neanderthalensis

The "Old Man of La Chapelle" was recreated from the skull and jaw of a Homo neanderthalensis male found near La Chapelle-aux-Saints, in France in 1908. He lived 56,000 years ago. His relatively old age, thought to be between 40 to 50 years old, indicates he was well looked after by a clan. The old man's skeleton indicates he suffered from a number of afflictions, including arthritis, and had numerous broken bones. Scientists at first did not realize the age and afflicted state of this specimen when he was first discovered. This led them to incorrectly theorize that male Neanderthals were hunched over when they walked.

Homo floresiensis

The skull and jaw of this female "hobbit" was found in Liang Bua, Flores, Indonesia, in 2003. She was about 1 meter tall (about 3'3") and lived about 18,000 years ago. The discovery of her species, Homo floresiensis, brought into question the belief that Homo sapiens was the only form of mankind for the past 30,000 years. Scientists are still debating whether Homo floresiensis was its own species, or merely a group of diseased modern humans. Evidence is mounting that these small beings were, in fact, a distinct human species.

Homo sapiens

Bones can only tell us so much. Experts often assume or make educated guesses to fill in the gaps in mankind's family tree, and to develop a sense what our ancestors may have looked like. Judging from skull and mandible fragments found in a cave in Israel in 1969, this young female Homo sapien lived between 100,000 and 90,000 years ago. Her bones indicate she was about 20 years old. Her shattered skull was found among the remains of 20 others in a shallow grave.