The partial skeleton of Homo floresiensis, found in a cave on the island of Flores, is of an adult female the height of a chimpanzee and with a skull the size of a grapefruit.
It is substantially different from modern humans.
It shared the isolated island to the east of Java with miniature elephants and Komodo dragons. The creature walked upright, probably evolved into its dwarf size because of environmental conditions and coexisted with modern humans in the
region for thousands of years.
It is believed to be an extinct Asian offshoot of Homo erectus, the forerunners of Homo sapiens, as anatomically modern man is called.
Floresiensis is the smallest of the 10 known species of the genus Homo, the hominid that is thought to have risen out of Africa about 2.5 million years ago.
"It is an extraordinarily important find," Professor Chris Stringer of the Natural History Museum in London said on Wednesday. "It challenges the whole idea of what it is that makes us human."
The remains were found on the
Indonesian island of Flores
Peter Brown of the University of New England in Armidale, Australia, and his colleagues discovered of the skull, other bones and miniature tools in September 2003 while looking for records of modern human migration to Asia. They
reported the finding in the science journal Nature.
"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," he said in a statement.
Local legends tell of Hobbit-like creatures existing on islands long ago but there has been no evidence of them.
The hominin family tree, which includes humans and pre-humans, is believed to have diverged from the chimpanzee line about seven million years ago. Early African hominins walked upright, were small and had tiny brains.
"It challenges the whole idea of what it is that makes us human"
Professor Chris Stringer,
Natural History Museum, London
The new species, dubbed Flores Man, is thought to be a descendent of Homo erectus, which had a large brain, was full-sized and spread out from Africa to Asia about two million years ago.
The new species became isolated on Flores and evolved into its dwarf form to conform with conditions, such as food shortages. Flores, which was probably never connected to the mainland, was home to a variety of exotic creatures, including a dwarf form of the primitive elephant Stegodon.
Modern humans had reached Australia about 45,000 years ago but they may not have passed through Flores. The scientists suspect the new species became extinct after a massive volcanic eruption on the island about 12,000 years ago.
Brown and his colleagues have found the remains of seven other dwarf individuals at the same site since the first find.
"The other individuals all show similar characteristics, and over a time range that now extends from as long ago as 95,000 years to as recently as 13,000 years ago - a population of Hobbits that seemed to disappear at about the same time as the pygmy elephants that they hunted," said Bert Roberts, one of the authors of the Nature study.