Careful study of the "Hobbit" fossil's wrist bones supports the idea that the creature was a distinct species and not a diseased modern human, it is claimed.
Matthew Tocheri and colleagues tell Science magazine that the bones look nothing like those of Homo sapiens; they look ape-like.
The announcement in 2004 detailing the discovery of Homo floresiensis caused a sensation.
Some researchers, though, have doubted the interpretation of the find.
These individuals - including the Indonesian palaeoanthropologist Teuku Jacob - have argued that the remains are probably those of a pygmy with the brain defect known as microcephaly.
But the new analysis by Tocheri, from the Smithsonian Institution in Washington, DC, US, and co-authors will add further weight to the original assessment.
Their study shows that the wrist bones of the Hobbit are primitive and shaped differently from the bones of both modern humans and even their near-evolutionary cousins, the now extinct Neanderthals (Homo neanderthalensis).
The creature's wrist lacks a modern innovation seen in both these other human species - a wrist that distributes forces away from the base of the thumb and across the wrist for better shock-absorbing abilities.
"The [Hobbit] wrist doesn't show the same specialization for tool behaviour as modern man or Neanderthals," Matthew Tocheri told the AFP news agency. "It retains the same primitive morphology as ancient hominids."
The 18,000-year-old bones of the Hobbit were unearthed on the Indonesian island of Flores, in a limestone cave at a site called Liang Bua.
