Scientists who argue the "hobbit" is really just a modern human with a small brain have published evidence for the first time in a major scientific journal.
Today's issue of the journal Science carries a paper led by primate evolution expert, Dr Bob Martin of the Field Museum in Chicago.
It says Homo floresiensis is likely to have been a modern human, who suffered from microcephaly - a condition that causes a small brain.
This reignites the debate about whether the remains of the small hominid from the Indonesian island of Flores is really H. sapiens or a dwarf version of H. erectus that evolved after becoming isolated on the island, as was originally suggested.
Dr Martin's team says that based on standard models of dwarfing, the hobbit's brain size is too small to be that of a dwarf.
It also argues the tools found alongside the hobbit are far too advanced to have been made by anyone but H. sapiens.
"If you look at the history of stone tools around the world Homo erectus never made tools like that," Dr Martin said.
"I've been in this business for 30 years and I really smell a rat in this.
"I don't think the standard story can be right and people are eventually going to see this."
His team also rejects findings of a study published last year that found the brain of H. floresiensis was unlike that of a microcephalic human.
Dr Martin says the study, led by brain evolution expert Professor Dean Falk of Florida State University, compared the hobbit with only one microcephalic, which he now says is a child.
He says the researchers should have been comparing it with a microcephalic adult.
Dr Martin's team describes the brains of two adult microcephalic specimens, a male from India and a female from Lesotho, it says are similar to the hobbit's.
In the same issue of Science, Professor Falk says this latest paper does not contain enough detail about the microcephalic specimens.
A co-discoverer of the hobbit, Australian researcher Professor Mike Morwood of the University of New England, who wrote the response with Professor Falk, stands by the dwarfing theory.
"What's happened with Homo floresiensis is paralleled very, very closely by a number of other endemic species on islands," he said, pointing to a goat-like creature called myotragus, found on Majorca.
Professor Morwood also rejects Dr Martin and team's idea about the tools and says it is important not to be overly focused on the hobbit's brain because its body shows it is not a modern human.
"It's got really long arms and incredibly short legs," he said.
"It's got really long feet and its bones are really thick."
But Dr Martin says the genes that affect brain size also affect the teeth and the rest of the skeleton.
So microcephaly might explain these unusual traits.
Comparing the hobbit with full microcephalic skeletons might shed further light on the debate.
Bur Dr Martin says these are hard to come by.