More Flores 'Hobbits' described, etc

Here are science news items, all about the `Hobbit' (Homo floresiensis), with my comments in square brackets.

More Flores 'Hobbits' described, BBC, 11 October 2005 ... Scientists have discovered more remains of the strange, small people that once lived on Flores island, Indonesia. The announcement last year detailing a single, partial skeleton caused a sensation when it was claimed to be a human species new to science. Homo floresiensis, as it was called, was little more than a metre tall and lived 18,000 years ago. Now, the same team tells Nature journal it has skeletal remains from at least nine of the "Hobbit-like" individuals. The new discoveries include missing parts of the old skeleton - designated LB1 after the caved dig site at Liang Bua - and a collection of other bones, such as jaw and cranial fragments, a vertebra, arm and leg bones, toes and fingers. The team, led by Michael Morwood ..., says the specimens have helped build a more rounded picture of LB1, with additional evidence of the little people's hunting and fire-making abilities. ... The researchers say they are now more convinced than ever that Homo floresiensis represents a distinct species and not some diseased individual of modern human (Homo sapiens)as some sceptics have suggested. "The finds further demonstrate that LB1 is not just an aberrant or pathological individual but is representative of a long-term population," they write in Nature. A critical line in their argument is the length of time which the new collection of remains represents - possibly 80,000 years - making a disease explanation for the cause of the little people's stature and shape an unlikely one. .. The team contends that Homo floresiensis, with its 380-cubic-cm-sized brain, is the outcome of a phenomenon known as endemic or island dwarfing. This sees isolated species, released from the pressures of predation but constrained by limited resources, evolving either smaller or larger forms than would otherwise be the case. In the case of H. floresiensis, it is said the creature could have come out of Homo erectus, a long-extinct early-human species that was known to populate Flores about 800,000 years ago ..: Daniel Lieberman ... said further discoveries on the island would help settle the issue. "If the island-dwarfing hypothesis is correct, then the island's earliest inhabitants should be larger than the Liang Bua fossils; and if dwarfing occurred gradually, then it might even be possible to find fossils intermediate in size and shape between H. floresiensis and its ancestor," .... "More evidence on when Homo sapiens first arrived on Flores is also needed." ... [Also at Independent Online, Livescience, New York Times & Washington Post. If these are indeed additional fossils of H. floresiensis, especially if they are thousands of years apart, then that would conclusively refute the diseased H. sapiens theory. See also two articles below.]

Hobbits' arms point to African relative, ABC, October 12, 2005, Anna Salleh ... Hobbits may have walked the Earth with modern humans but their body shape and size are more like a 3-million-year-old from Africa known as Lucy, scientists say. Australian researcher Peter Brown ... says the latest findings shed light on how our early relatives dispersed across the globe. "It supports that small-bodied, small-brained bipedal apes came out of Africa much earlier than previously thought," Professor Brown said. The findings also question whether hobbits arose from more recent human relatives Homo erectus, as once proposed. In the current issue of the journal Nature, Professor Brown and colleagues report on more hobbit bones from the Liang Bua cave on the Indonesian island of Flores. Their analysis shows some similarity to Lucy the australopithecine. [sic] "The only creature which ever had these body proportions apart from the Liang Bua material was the Lucy skeleton, nothing else," Professor Brown said. Key bones that helped the researchers work out what the hobbit's body really looked like came from its right arm. "The arm is spectacularly long in relation to body height and the length of the leg," Professor Brown said. He says the hobbit's short and stocky body and long arms are unlike any other members of the genus Homo. And this is supported by evidence from other parts of the 260-bone skeleton, he says. "The evidence we have from those 260 bones is pointing to something other than Homo erectus or modern humans. It's pointing towards an australopithicine," he said. Professor Brown says the relationship between the hobbit's brain size and body size is "exactly" the same as that of chimpanzees and australopithicines. All this has made Professor Brown and team seriously question their original idea that the hobbits evolved from Homo erectus that dwarfed on their island home. "To me the Homo erectus dwarfing is looking less likely, particularly because of the brain size, body size relationship. It's not what you'd expect to get," Professor Brown said. He now believes the hobbit is descended from an as yet unknown small-bodied and small-brained ancestor closely related to an australopithicine. ... [See also Christian Science Monitor. As I posted to my now terminated list CED (30-Oct-04; 02-Nov-04; 30-Nov-04; 18-Dec-04), and here on my blog CED (16-10-05), my view from the beginning was that this Flores man was a separate line that descended from Australopithecines. This would falsify the theory of H. Floresiensis' discoverers that its small stature was due to island dwarfism. But I am sure they would not mind!]

Hobbit debate flares up in science journal, ABC, Anna Salleh, 13 October 2005 .. The controversy over whether the hobbit is just a sick member of the human race has flared up again, this time in the pages of a prestigious scientific journal. Dr Jochen Weber ... and team report they have found a tiny human brain that looks like a hobbit's. Their study, to be published in the journal Science, looked at the brain casts of 19 humans with microcephaly, an illness that causes a small brain. They disagree with an earlier study of brain casts, by Professor Dean Falk ... and team, which ruled out the hobbit brain as being that of a microcephalic. But the German researchers says the microcephalic brain Falk's team studied was too limited a sample for comparison. The German team studied microcephalic brains with a volume between 280 and 591 cubic centimetres, and a mean value of 404 cubic centimetres. This, they say, is comparable to the hobbit brain size of 417 cubic centimetres, as measured by Falk's team. "The virtual cranial capacity estimate for Homo floresiensis is well within the range of variation for microcephalic brain volumes," says the latest research. The researchers also picked out one particular microcephalic specimen with a capacity of 415 cubic centimetres and found it was "nearly identical" to the hobbit's brain, based on six dimensions or "diagnostic indices". The researchers also cite other evidence that the microcephalic brain is comparable to that of early hominids and conclude that it is not possible to rule out the hobbit was a microcephalic human. ... Falk and colleagues, including Australian co-discoverer of the hobbit, Professor Mike Morwood ..., respond to the microcephalic study in the same issue of Science. They say that Weber and team don't provide the measurements used to calculate the indices they compared. Falk, Morwood and team also say the pictures of brain casts provided in the German microcephaly paper don't allow them to compare the hobbit's brain with the human brain supposed to be virtually identical to it. ... Morwood says the hobbit's brain should not be considered in isolation from other aspects of its skeleton that clearly rule it out as a modern human. "This particular brain is attached to an individual with lots of other really unusual characteristics," he says. "Some of them are really primitive, some of them are really unique." Morwood says these traits include the length of the arms and the thickness of their limb bones, which are both identical to Lucy, the 3-million-year-old australopithecine from Africa. The hobbit's pelvis, teeth, jaw, ear region and lack of a chin are also unusual. Even without the hobbit skull, there is still enough evidence to exclude it from being a modern human, he says. ... [See above, especially Dean Falk's response. As I commented on 24-Sep-05, I doubted that this was a microcephalic modern human, and if it is confirmed that there are additional H. Floresiensis fossils found in different strata, that would falsify that theory.]

Stephen E. Jones, BSc (Biol).
"Problems of Evolution"