Showing posts with label Fossils. Show all posts
Showing posts with label Fossils. Show all posts

Friday, September 21, 2007

The 'Hobbits' of Flores: Hasn't anyone figured them out yet?


Last updated September 26.

` On the Indonesian island of Flores, the natives tell stories of a long-gone, diminutive and hairy 'cave people' called Ebu-Gogo. Ebu means 'grandmother' and gogo means 'one-who-eats-anything' - they were said to have lacked cooking skills. These human-like creatures are said to have constantly raided crops and eaten anything they were given, from raw meat to the gourd-dishes the food was placed on!
` They were said to be no taller than three feet with long hair, pot bellies, ears that stuck out a bit, longish arms and fingers, and a slightly awkward gait - they were clearly built for walking, but could also climb slender trees very well.
` Ebu-Gogo women were noted for their long breasts which they reportedly slung over their shoulders. (The women of the village Labuan Baju in the far west also have somewhat long breasts and therefore the 'LBJ' villagers are often made fun of for allegedly interbreeding with the Ebu Gogo!)
` Though they were said to be able to 'murmur' to one another in some form of speech, talking to the Ebu-Gogo was described as being rather like talking to a parrot - you could say whatever you wanted to them, but they would only repeat what you had said.

` Now, there are many convincing explanations for similar stories of 'little people' the world over (some that involve short humans and some that don't), though the Ebu-Gogo legend is distinguished by being the only such legend to potentially (maybe, perhaps, plausibly) have more literal credence since the discovery of tiny homonin fossils in a cave called Liang Bua.
` The small-brained people are tentatively named Homo floresiensis - and commonly are known as 'hobbits' - though it is unclear exactly how closely they are related to us. However, since the 'hobbits' may have gone extinct ten thousand years ago or further, the idea that the natives' stories were passed down from memories of living individuals is doubtful.

` Nevertheless, it is possible that the natives may have come across these small skeletons themselves and made up the tales to preserve the knowledge of the old bones:
` It is well-documented that people of other cultures have done the same thing. Among Native Americans for example, a gigantic vulture-like bird preserved in a cave seems to have sparked stories of a terrible bird that ate people; bird-like dinosaur footprints are used as religious symbols, thought to be the tracks of thunderbirds or sky-gods; mammoth skeletons were thought of as the bones of mythical giants or great beasts; skeletons of large mammals and dinosaurs seem to be represented quite often in myths about the development of the earth.

` In any case, there is proof of very small people who really did live on Flores - right alongside modern human beings, in fact! Since that discovery, in 2003, the question has been raging; how much like us were they? Are they even a different species?


` This was my take on the first reports of the first 'hobbit' find: Moisture-softened bones (like 'blotting paper') from several of these these Homo floresiensis were found spanning several layers in Liang Bua alongside those of animals such as giant monitor lizards, dog-sized rats, and miniature versions of prehistoric elephants of the genus Stegodon.
` In addition there were the remains of firepits (evidently they could cook) and numerous stone cores, flakes, reworked tools (points, blades, microblades) and anvils that look like they could have been made by our own species. The bottom-most remains dated at 94,000 years ago to the most recent at about 14,000 or 13,000 years back - and through it all, the tools stayed the same.

` The official opinion was that they might be a miniature version of something like Homo erectus, a species that lived in the region, which might have migrated to the island and become smaller after living there for several generations - much like the many miniaturized instances of other species, such as the pygmy Stegodon.
` In fact, every so often the Stegodons would go extinct and then more large ones would migrate over from the mainland and shrink, one population after another. Evidently, it was an easy enough place for them to get to, though they most likely swam considering that herds of elephants can sometimes be seen swimming out to sea towards islands. (Many islands, anywhere from off the coast of California to just north of Russia, were also populated by very small versions of mainland elephant species.)
` How H. floresiensis ended up there, no one can say. Though the nearby island of Java used to be populated by H. erectus, it had also been connected to the mainland by a land bridge. Flores wasn't, as far as anyone can tell. It is tempting to think that 'hobbit' ancestors were capable of making boats, though there is also no evidence of this. Whatever happened, once they got there, they stayed there, and assuming they had once been bigger, they shrank.

` Miniaturization is common in rainforests or islands (or rainforested islands like Flores), which are environments with few available nutrients. Presumably it happens because a healthy breeding population is not so easily supported on the available resources at the species' 'normal' size. In these types of environments, native peoples can be found who rarely grow much taller than five feet - this includes African, Melanesian, New Guinean and Southeast Asian groups.
` A complete female H. floresiensis skeleton shows an individual that was much smaller - only three feet tall and around fifty-five pounds in weight, with longish arms. From what is known about an individual known as LB1 (a.k.a. 'Ebu' or 'Our Little Lady of Flores') - they had a face similar to ours, yet the cranium was the size of a grapefruit, more like that of a much older human relative, the similar-sized Australopithecus.
` The team determined that the skull was from an adult individual - around thirty years of age - from many clues, not the least of which was that the permanent molars had all erupted and had undergone years of wear.

` Early on, the scientists wondered if a person with such a small brain could be capable of making tools that resemble those of our own species from many areas of the world, while Homo erectus fossils have never been associated with anything this advanced.
` It could be that they had gotten the tool ideas from humans - who lived alongside H. floresiensis for roughly 45,000 years - though from elsewhere, as humans had presumably arrived on the island thousands of years after H. floresiensis established their first colony and primitive technology.
` What seems to be much more likely is that they had figured it out on their own. After all, the largest genetic difference between us and chimpanzees concerns genes that affect the way the brain functions, and a human brain is structurally different from a chimp brain:
` Judging by the inner surface of the skull, H. floresiensis had a rather human-like brain. Though chimps and 'hobbits' had similar-sized brains, perhaps this is not quite as large of an issue as it seems!
` However the tools came to be, they evidently were made by H. floresiensis, as they were smaller than tools from H. sapiens, and not surprisingly, the right size for them. The little people were also apparently organized enough to hunt and butcher Stegodons, especially young ones, whose bones - which also show evidence of being cooked - were much more common in the cave deposits than adult remains.

` How unusual - a species that was incredibly small, seemingly had high intelligence, and yet what a small brain! It only got stranger.
` A bit later on in time I had read science reports that attempts to find similarities between the H. floresiensis braincase and those of people who were pygmies or who had dwarfism or microcaphaly had continued to fail.
` Archaeologists like Peter Brown and Richard Roberts reported that the fossils had many Australopithecus-like traits (besides those that occur from having a short stature), and interestingly none of these had been recorded in modern humans of any kind.
` Their detractors insisted that perhaps these were merely some growth-challenged people and that the skull that had been found just happened to be from a microcephalic - which is funny, because people with microcephaly don't tend to live very long.

` A few months later, I continued trying to find information about more published studies concerning the 'hobbits', but they seemed to have had stopped at the moment.
` Then I discovered a potential reason why when I came across interview transcripts from an Australia Broadcasting Corporation show called Lateline. The first transcript (Nov 25, 2004) is an interview by Tony Jones of the aforementioned Richard Roberts at the University of Wollogong.
` They discuss the huge amount of drama concerning a professor Teuku Jacob - who was not involved with the project - taking the team's findings and claiming that they were modern human bones! He allegedly kept them away from anyone who disagreed with his viewpoint and seems to have even told a few lies to help justify his behavior.
` This, in my opinion, is even more sensational than the idea of a tribal legend with parallels to a fossil species! I mean, scientists may be scientists, but sometimes there will be some who fail to act accordingly.
` Jones and Roberts comment on what had happened...

TONY JONES: It's an extraordinary situation. This was billed as one of the great scientific discoveries of our time?

PROFESSOR RICHARD ROBERTS: It is. It has moved beyond science now into the political arena. We're trying to take it back to the scientific arena which is where it belongs.
It shouldn't be used as a trophy to trade around as a power base. It is something for the scientific community to say; 'This is what it is or isn't.'
I don't object to Professor Jacob having a different view from ourselves. I think he should let others look at the material and he can come to his own conclusions as can everyone else.
` It is strongly implied that Jacob was not being objective. So, why do most of the archaeologists involved - or otherwise - think that Jacob's opinion was wrong? And why did Jacob insist he was right? I found this to be rather telling;
PROFESSOR RICHARD ROBERTS: ...Microcephaly is an extremely rare disease amongst modern humans.
The fact we have found a human with microcephaly would be an acheivement. The probabilities of finding it are vanishingly small. The fact that we now have seven indiviuals, from this cave, presumably all with microcephaly... the chances of that are utterly remote.
Let's take a point of argument that this particular individual with a small brain is a microcephalic individual, is such an individual. They have other features that indicate they're not suffering from microcephaly, they have unusual tooth structures - three roots to the teeth.
You find those in three-million-year-old people like Lucy in Africa, that only exist in very early Homo erectus. You don't find those with modern humans. We don't suddenly develop three roots to the teeth. Nor do you suddenly develop long arms if you have microcephaly. And that's what the hobbit has, they have slightly longer arming compared to ourselves.
The pelvis is wider than in modern humans. They have very thick eyebrow ridges. None of these are features of microcephaly. When you look at a complete set of features of the skeleton, one or two of them might be credible as being microcephalic problems, but the rest of them can't be explained by microcephaly.
If you pick some of the ones like Professor Jacob has done I can understand how he reached that conclusion. But not on the basis of all available features.

...None of the referees on the papers, and we had lots of them, of course they were looking for something simple like this, saying it's a modern human suffering from a medical problem, it's something the referees on the paper thought 'is this going to be the explanation?' and they quickly reached the conclusion, 'it's not the explanation.'
This is definitely a new species of human. In fact, so different, originally Peter Brown even thought this was a new genus of human, that's how different they are. Professor Jacob is really out there by himself.
Interestingly, it is history come full term again. Every time a new human species is discovered, suddenly everyone is saying it's some sort of demented modern human.

TONY JONES: I was going to say you have to be a bit philosophical about it. This is pretty much what happened with the Neanderthal man?

PROFESSOR RICHARD ROBERTS: That's right. They were first thought to be some poor cossack who got stuck in a cave and died or some demented human.
Same with the first Homo erectus, Java man, people thought; 'Oh, look, he's a sad case of a poor soul who's a demented human.' As the fossils began to accumulate, everyone says, 'No, that's not the case.' We've now got too many 'demented humans' for that to be an explanation. It's a new species.

TONY JONES: From Professor Jacob's point of view there's some history here. He refers to a Dutch Priest called Verhoven who made similar claims for a discovery in the 1950's, at least that's who the professor is saying. It appears he was directly involved in refuting those claims. Is history repeating itself for him?

PROFESSOR RICHARD ROBERTS: Verhoven was the first person who found this cave. He was a very talented archaeologist, be he was a full-time priest, or was supposed to be a full-time priest, but he did an awful lot of digging but never dug deeply, only about the first two or three meters, then stopped.
All he ever did find was modern humans. If Verhoven claimed it was another human species, Verhoven would have been wrong. So Professor Jacob might have been right then but I don't think he's right on this one.
` I then learned more about the controversy, both over Jacob's actions and concerning H. floresiensis biology. And where? Another Lateline interview (March 3, 2005) with Richard Roberts and one of the people who agree with Teuku Jacob.
` That person is Maciej Henneberg, who also claims that Jacob was not hoarding the specimens. Roberts disagrees, explaining that Jacob and the discovery team would have to agree before allowing a third party to look at the find. Jacob didn't do this. Roberts then claims that the only people Jacob let look at the remains were those few who actually agreed with him.
` Finally, he says that Jacob relinquished the find after he was forced to, though he wouldn't have done so voluntarily. (It was badly damaged from human handling as well.)
` He also talks about the comparison with the brain endocasts of various diseased human individuals and prehistoric species, and how the results oppose Jacob's (and Henneberg's) viewpoint.
TONY JONES: Maciej Henneberg, are you prepared to reconsider your position on the basis of the endocast results if they do indeed show that the brain of the hobbit is not a diseased brain as you seem to be suggesting it is?

MACIEJ HENNEBERG: I'm not, and the reason is that... [t]hey compaired [sic] it to one single brain of a person who has the kind of microcephaly that we never suggested the LB1, the skeleton in question, ever had. So it's like comparing a patient with tuberculosis to a patient with bronchitis or pneumonia. I don't think it bolsters their case in any way.

TONY JONES: Let's speak about your other objections or your other views about why this skull and the other bones are not the bones of a new species.

MACIEJ HENNEBERG: Well, I have now had an opportunity to study the skeleton. I must add that, when I did any discoveries on skeletal material, I welcomed my colleagues to come and have a look, especially those colleagues who had a different view because I thought that when they come and look at the original material they can change their minds, and I'm talking only about looking at the bones that were already described.
Those bones clearly indicate that the person suffered from a growth anomaly and this growth anomaly caused anomalous, very slow or retarded growth of the brain....

TONY JONES: Richard Roberts, I know you know some of Professor Henneberg's other criticisms. He is suggesting that, in spite of what you're saying - that it's... the brain of a hobbit, a new species of human, but a normal brain, not a diseased brain - how do you answer the claims that it is in fact diseased without referring to the endocast?

RICHARD ROBERTS: Professor Henneberg, in a paper which I've seen in a journal, not a referee's paper but one where he expresses a point of view, pointed out some features that he believed to be that of a microcephalic individual.
Peter Brown, our expert paleoanthropologist, pointed out in reply that, while individual features such as a very small brain, such as certain things like even perhaps a slightly receding chin or sloping forehead, are consistent with a microcephalic individual, lots of details are not consistent.
In fact, they've got nothing like that in microcephalic individuals ever reported. So, when you consider the whole package of features that we found in the skeleton, and not just the facial features but also the post-cranial features, the rest of the body, it has a very flared pelvis and arms that come down almost to the knees - these are not conditions that occur with microcephalic individuals.
So, when you consider the whole overall anatomy of this person, it doesn't wrap up into a microcephalic person.

TONY JONES: Is the problem here there's only one skull? I know there's a part of another skull - I think it's the mandible -

RICHARD ROBERTS: That's right. We've got two lower jaws, and they're both very, very similar to each other which again argues against the fact that we've now got two microcephalic individuals and we've got the remails [sic] of eight individuals now from the cave, so if they're all equally small, which they seem to be, then if Professor Henneberg is right we've found eight microcephalic individuals and it's an extremely rare disease and to find eight of that antiquity would be quite a remarkable find.

TONY JONES: Professor Henneberg, you couldn't possibly have a nest of diseased individuals in this cave, could you, so how do you answer that?

MACIEJ HENNEBERG: We don't. There is only one skull. The so-called seven or eight, they seem to be multiplying now in the discussions, individuals are represented by mostly a single bone or a little bone fragment, like a fragment of a Spinous process of a vertebrae. And those have nothing to do with brain size. The only thing they indicate is small body size of local population....
...there's only one - and I stress it - one brain case and actually one face attached to it, and this face is fitting into modern human range of sizes and has a lot of features Australian and Indonesian people who, yet again, live in Flores and islands to the east of Flores until today....
It's not normal to have this amount of asymmetry in the face. When we come to long bones, they are actually unusually wide in relation to their rather short length and, yet again, this is indicative of abnormal growth, not of growth that is compatible with a new species. Let me finally straight out say that we are not discussing fossils at all.
Neither the skeleton LB1 or any comparing remaining bones, but we didn't really study them, neither of these are fossilized. They're as fresh bones as those that are excavated - I have excavated several thousands of them - from cemetaries and burial grounds that are a few thousand to several hundred years old. This is not a fossil.

RICHARD ROBERTS: Preservation is a geological issue and the particulars of preservation in this case are a wet, damp cave environment can keep things soft for a very long time. It certainly isn't fossilized in terms of minerals getting replaced in the original bone but it's certainly an extremely old skeleton, about 18,000 years old.
The fact that it's not completely mineral-replaced is neither here nor there. It's a complete red herring....
He talked about a slightly deformed skull. Of course we found this skeleton six meters underground. A cubic meter of sediment weights 2.5 tonnes - you'd feel pretty squashed too if you were stuck under six meters of sediment.
So you're going to expect some amount of crushing of the original skeleton when it's that deep underground.....
...What he was saying about the fact that referees never had a chance to look at the skeletal material, it should be said that Professor Henneberg, three days after we published our paper, was quite happy to write himself in the Adelaide Sunday Mail what he thought about it without having seen a specimen himself and he had already made his mind up. All he's done by going to Yogyakarta is made up his mind further. It was always a microcephalic to him. No amount of data will change his mind on that subject.
` It certainly does sound like Henneberg is biased, though I thought his point about not having several skulls was a good one. Nevertheless, if you have a skull and then another almost identical, primitive-looking jaw (with no chin) that could well fit onto the same type of skull, it seems reasonable that they were once articulated with a similar skull.
` Not surprisingly, there is even another transcript from the very next day concerning the speciment' brain shape - and even its texture, which was convoluted like ours!
RICHARD ROBERTS: Foreward planning activity happens in the front of the brain, and that's where the hobbit brain is really well-developed. That explains a lot of mysteries that we had the first time around, which was; 'how could something with a brain the size of a grapefruit do so many sophistocated activities?'
...Importantly the study concludes that these features are almost certainly not from a modern human suffering from a brain disorder....

PETER BROWN: They are not consistent with the size and shape features which you might expect to find in a pathological or abnormal modern human. They are normal brains, they just happen to be different to modern humans and different from those in Homo erectus and much smaller than Homo erectus in overall size.

RICHARD ROBERTS: Professor Henneberg said they only looked at one microcephalic individual's brain, and that's true. But out of all the brains that they compared the hobbit to, the microcephalic's was the least like the hobbit's brain; that is, this brain was so distinctively different from the microcephalic it really is very, very improbably [sic] that it was somebody suffering from microcephaly.
` I wonder, then, what it is that tells them that there's no problem. How can anyone tell if there's something 'diseased' about a new type of braincase? I'm assuming there are telltale places of abnormal growth, though I still haven't been able to find what they are.
` Anyway, I know it's strange to be so clueless as where to find the latest scientific information that you will seek it out from television interviews - but as I later learned from science articles and news reports, this was a fairly accurate picture of what had been going on.
` For example, in Nature's July 1, 2005 EMBO 'Science and Society Report' was an article called Skullduggery by Tabitha M. Powledge. It described what had gone on with the archaeological community being in an uproar over Jacob, and that most other paleoanthropologists didn't agree with him. However, I was not aware that the bones had been damaged when Jacob finally returned them to Jakarta (February 2005):
The bones had been seriously damaged: the pelvis had been smashed, the second mandible had been broken and unskilfully repaired [glued back on at the wrong angle], and LB1's skull had been mutilated by latex moulding; Science published photos of the damaged pelvis (Culotta, 2005).
Morwood charged that bones with australopithecine traits had been almost destroyed. "The condition of some finds is absolutely appalling," he said. "This is not the action of responsible scientists." Jacob acknowledged taking moulds, but says he has photos showing that the bones were in perfect condition when they left his care.

Meanwhile, a study of LB1's brain, based on skull endocasts made before the bones were moved, was also published (Falk et al, 2005). First author Dean Falk of Florida State University (Tallahassee, USA) concluded that the brain was unique and somewhat erectus-like, but had advanced features, such as an enlarged prefrontal cortex, that hinted at respectable cognitive capacity.
Comparing it with a single skull from a microcephalic, the group also concluded that LB1's brain was not altered by disease. Falk is now studying additional microcephalic endocasts for comparison. "This was just a thrill," she said. "We said to them, 'We stand ready. If you find any more skulls, we'd love to analyze them!'"
` I later found that Falk compared the LB1 endocast to those of nine microcephalics, showing that the brain had no discernible growth problems but did have its own unique characteristics, suggestive of being a different species.
` Really, the whole debate seems to have been fruitless for Jacob's part and the article ends by describing how this drama has been used as fuel by critics of science (especially of evolution) by giving them something to scoff at. You know, the old 'obviously they don't know what they're talking about' line! (A similar thing happened when Pluto was reclassified - what is going on in that case is that 'planet' is an ancient term and it has been hard to adapt as a scientific one.)

` So far, further attempts to place the fossils into our species have continued to be unconvincing. As recently at June of this year, a team led by Israel Hershkovitz et al published a study that supposedly demonstrates that LB1 is nearly indistinguishable from a person with Laron Syndrome.
` So, I looked the condition up and discovered that those with Laron syndrome do not have grapefruit-sized brains, along with quite the opposite of sloping foreheads. See for yourself.
` It turns out that Richard Roberts also considered this possibility, though he decided that it didn't make any sense for these reasons and others. Though there are some striking similarities with other characteristics, this could mean something else:
` What could it mean? That's not clear. I could speculate. It's dangerous, I know; Perhaps this is what happens to H. erectus when it has the Laron syndrome mutation? But then... all the individuals found - from different millennia, no less - would then appear to have had it. Plus, the tools in the caves seem to be dwarf-sized. There is also no evidence of larger individuals in the same deposits.
` Perhaps it represents a mutation that was adaptive? And now I seem to be getting back to the original hypothesis....

` Yesterday, however - this is actually what inspired me to throw this whole post together - I had stumbled into a Nature News article that describes how the wrist bones of H. floresiensis were characterized as being almost the same as those of Australopithecines!
` What?
` Matthew Tocheri from the National Museum of Natural History (Washington DC) led a team who made detailed measurements of trapezoid, scaphoid and capitate bones of various wrists including H. floresiensis, humans, Neanderthals, great apes and Australopithecus. Microcephalics and pygmies were left out, however.
` Still, the study concluded that the wrist bones of apes and Australopithecus were more similar to the H. floresiensis wrist than modern humans - including those with dwarfism - and Neanderthals. In fact, there's even a visual provided:
The ape-like trapezoid bones of the hobbits, for example, are tapered and wedge-shaped, in contrast to the 'boot-shaped' trapezoids of modern humans, Tocheri and his colleagues explain (see picture).
` If H. floresiensis inherited its wrist bones from a long line of primitive ancestors, their common ancestor with ours would have lived before eight hundred thousand years ago. Why? Because that is the age of the earliest-known modern human wrist - just the type of wrist to make tool use easier!
` So, our lineages would have split ways a long time ago, and possibly longer assuming that H. erectus also had modern wrist bones - of which none have yet been found, strangely.

` While I did consider that Roberts may be wrong for a while, I'd say that from this latest find that these might really be a different species from our own. At least, any argument for H. floresiensis as being mutant H. sapiens does not seem very impressive. Only further finds and barrages of tests will tell....
` And I'm sure once this is all worked out, maybe some people can move onto working themselves into a lather with even more enigmatic questions... such as; 'Do the legends of the Ebu-Gogo have anything to do with the extinct creatures of Flores?'
` I'll probably be taking a mental-exhaustion-induced nap.


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