The discussion about the status of homo floresiensis.

Author: Carlos A. Marmelada. carlosalbertomarmelda@yahoo.es

Index

1. The advertisement of a surprising news item

2. Morwood's early findings

3. The Flores Island Man finding

4. Why was Homo floresiensis so small?

5. The first criticisms

   1. Microcephaly and dwarfism

   2. Technology too advanced

6. The bones of discord

7. Computed tomography (CT) analysis of the skull of LB 1

8. Criticisms and counter-criticisms of Falk and colleagues' article

9. The reply of Falk et. al.

10. New criticisms

11. The Falk et al.

12. New discoveries

13. The lithic industry of Mata Menge

14. The most recent criticisms

15. New data on the skull of LB 1

16. Brain shape in microcephalic humans and in Homo floresiensis

17. The study of the lithic industry of Southeast Asia

18. The structure of the shoulder of Homo floresiensis.

19. The structure of the wrist of Homo floresiensis

20. The uncertainty of the origin of Homo floresiensis

21. Notes

On 28 October 2004, one of those news items that shocked the world of science hit the media speech worldwide. On that day, the prestigious journal Nature published two articles* (1) that stunned many specialists in human evolution. In these articles Peter Brown and Michael J. Morwood (both from the University of New England in Armidale, Australia, and co-leaders of a joint team of Australian and Indonesian scientists from research ) announced that they had discovered in a cave on the Indonesian island of Flores * (2) the partial skeleton of an adult female human who had died 18,000 years ago, and who was only just over a metre tall and had a brain of 380cc, a brain volume slightly less than that of humans, a brain volume slightly smaller than that of hominids more than three million years ago, such as Australopithecus afarensis, and similar to that of chimpanzees (380 cc). According to the discoverers, it corresponded to a healthy individual which they therefore assigned to a new human species: Homo floresiensis * (3).

Of course, the news was so surprising that it even seemed like a joke. Juan Luís Arsuaga said of it in ABC.es that: "Until yesterday* (4) I thought that to play a joke on a paleoanthropologist colleague I would give him the news that an australopithecine had appeared in a place in La Mancha, whose name would then be remembered all over the world. What is reported in Nature is far more incredible; and yet we have to accept that it is true. At least for the time being" * (5).

The final clause is precisely the crux of the matter. It is on this that we will develop this work. The advertisement of finding is so incredible that many sceptical voices were soon raised. However, both its discoverers and a good issue of scientists have refuted one by one all the criticisms that have been made to the thesis that Homo floresiensis is a human species different from us and from any other, with the peculiarity of having a very small stature, a scarce metre (we repeat that we are talking about healthy and adult individuals), and a tiny brain that was around 400 cc.And yet, with enough intelligence to make stone tools as complex as those made by our direct ancestors the Homo sapiens of 20,000 years ago; and more very important things, as we will see below.

What we are going to analyse is precisely the historical development of this polemic. That is, the analytical chronicle of discussion. We will begin, as is logical, by looking at what Brown and Morwood affirmed in the two articles cited. Then we will look at the first criticisms made of them, then we will analyse the first replies, and so on until we reach the latest works that have been published this year. But first we will see what were the results of Morwood's first works in Flores.

Morwood's early findings

Mike Morwood, one of the co-directors of the team that discovered Homo floresiensis, had been working on the island of Flores for several years. In fact, in 1998 he announced the finding of lithic industry with an antiquity of around 800,000 years * (6). Although the existence of stone tools of this age in this area was admirable, what was really surprising about this finding was neither of these two things, since, in fact, samples of lithic industry of a similar age, and older, had already been found in the Indonesian archipelago. Where, then, did the admirable thing about this finding lie? Nothing more and nothing less than the exact place where it was found: the island of Flores.

Why? For the simple reason that Flores has never been attached to the mainland. That is to say, it has always retained its insular status regardless of the planet's climatic fluctuations, which resulted in water concentrating at the poles when temperatures were low, with the consequent regression of the seas and the increase in the mass of the emerged continental shelf, something that made it possible for many of the world's current islands that are close to the coast to be linked to it by an arm of land. This was never the case of Flores; however, there have been times when a large part of the Indonesian archipelago (all its central and western part: Java, Sumatra, Bali, etc...) was linked to the current Malay Peninsula (or Malaysia); and, in general, to all of Southeast Asia (Malaysia, Thailand, Vietnam, Cambodia or Kamphuchea and Laos), forming the geographical unit known as the Sunda Peninsula or Sonda. Flores has always been separated from the Sunda Peninsula by a waterspout, the so-called Komodo Strait.

What does all this mean? One thing is quite obvious: that the makers of these stone tools had to reach Flores by sea. This is something truly exceptional and totally unexpected.

Until 1998, the oldest evidence of navigation was believed to be 60,000 years old (60 kyr.) * (7) and corresponded to the first doubling of northern Australia by members of our species, Homo sapiens, who arrived in the area by sea.

Today the area between Flores and Java is punctuated by a series of islands, including Bali, Lombok, Sumbawa and smaller ones, including Comodo, which lies just off the western edge of Flores: Bali, Lombok, Sumbawa and smaller ones, including Comodo, which lies just off the western edge of Flores. Of all these islands, the westernmost ones were part of the Sonda Peninsula. The easternmost ones were not. But they could play an important role in allowing "frog jumps", which would facilitate navigation to Flores. In any case, the human presence on that island more than 800,000 years ago gives much food for thought.

However, at the beginning, not everybody agreed agreement to admit that the origin of these tools was anthropic. The scepticism stemmed mainly from the fact that Flores had never been attached to the mainland, which meant that those humans must have reached Flores by sailing through the dangerous Commodus Strait. If that was so, then theerectus should be considered the first navigators in the history of mankind. An honour that until then had been accorded to theapiens who, almost seven hundred thousand years later, would have reached Australia from an island in Indonesia. It was really too shocking to be accepted at face value.

However, the controversy was settled in the summer of 2006, with the publication by Morwood and collaborators of a work in which they announced to have discovered 507 new tools with an antiquity between 840 kyr. and 700 kyr. But we will talk about them later because they play an important role in relation to Homo floresiensis.

The finding of the Man from the island of Flores * (8)

Let us go back again to 1999. At that time Morwood decided to undertake further excavations in other places, in order to confirm that humans had arrived in Flores at a very early date. For this purpose they went to the Liang Bua cave. In the summer of 2003, the researchers had a big surprise. Indeed, when they were working in sector VII, several human remains were unearthed, including a tiny skull: all the remains belonged to the same individual and were found in a level that was 18,000 years old. From the shape of the pelvis they concluded that it was a female and from the wear on the teeth they deduced that she had died when she was about 30 years old. Her small stature, around one metre, led them to think at first that she was a young girl. But when they observed the dental wear and the presence of the wisdom tooth, they had no choice but to accept a truly astonishing fact: this was an adult individual! With all the implications that this entailed. His short stature was therefore not a question of his age at death, but a specific characteristic.

The fact that it had a similar height to Australopithecus and early humans (Homo habilis and Homo rudolfensis) and a brain similar to that of chimpanzees, but with an excellent aptitude for making very complex tools, as well as the possession of other archaic anthropological traits, led its discoverers to lump these specimens into a new human species: Homo floresiensis.

It was possible that they might have come across an exceptionally short individual of our species due to some anomaly in its growth. However, this hypothesis seemed out of the question, as the team researcher had previously found, in another site on the island, an arm fragment from another individual of the same species, but with an age of 38 kyr, which suggested that the individual to which it belonged was also around one metre long. Its discoverers ruled out that it belonged to our species but that it was a pygmy, since the body development of these sapiens stops at the end of adolescence, but then their brain has reached a size as large as that of any other sapiens, while "Hobbit"* (9) died as an adult female.

In this regard, and somewhat anecdotally, Henry Gee, director of Nature magazine, warns that this finding should lead us to reconsider the Degree veracity attributable to the legends that the natives of the island explained to the Dutch navigators who landed there; stories that made reference letter of the existence of mysterious humans (the ebu gogo) who were about one metre tall and lived in the interior of the forest.

Why was Homo floresiensis so small?

One way for herbivorous species to defend themselves against predators is to resort to megadontia, i.e. to develop a disproportionate growth of their bodies to prevent or hinder carnivores from eating them. However, in the absence of predators, when a population of large herbivores is geographically isolated in a small area where food resources are scarce, the only way for it to survive is to reduce its size (for example, on the island of Sicily, elephants have reduced their size to only 250 kg), so that after a while this population evolves giving rise to a new species which, although it is an heir or descendant, is already different from the parent species.

Initially Brown thought that this evolutionary mechanism was the one that must have allowed the emergence of the Homo floresiensis. An ancestral population of Homo erectus could have arrived sailing (something already admirable) to the island of Flores; there it would be isolated and would evolve until giving rise to these tiny humans. If this was so, it would mean, according to Brown, that hominids, and therefore humans, would be subject to the same evolutionary forces as other mammals. This is not only reasonable, but even obvious: it is logical from a biological point of view, just as from a physical point of view man is governed by the laws of gravity, like any other body. The scientific and philosophical problem is to determine to what extent the brain can be reduced in size while retaining all the intellectual abilities of a human being. At the end of the article we will deal with the topic of the existing hypotheses about the origin of H. floresiensis.

Despite their diminutive size, they hunted animals such as extinct dwarf elephants (Stegodon), mainly the young, giant lizards, the famed Comodo Dragon, which is still extant, and other animals such as snakes, turtles, frogs, rodents (also giants) and bats. Since the bones of some of these animals have been found charred, it is believed that floresiensis must have mastered fire.

Thousands of lithic tools used for skinning, butchering, tanning or drilling have also been found at Liang Bua. Many of these tools appear in sediments that are 78 kyr old. We know that H. sapiens did not arrive in Flores until about 12 kyr ago, so he must not have been the maker of these tools. But then... who is the author of these tools from Flores, so similar to those made at that time by the Neanderthals in Europe and by the Sapiens in Africa and other parts of the world? At first there was no certainty, because it could not be ruled out that anatomically modern humans had arrived on the island much earlier than the fossil evidence that has come down to us. But in the summer of 2007 the matter seemed to be back on track with the publication of the work on the Mata Menge tools mentioned above, which we will discuss in more detail later.

The first criticisms * (9)

Microcephaly and dwarfism

 

It is logical that in the face of such a surprising and revolutionary finding , critical voices were raised in an attempt to provide a more conventional explanation. Thus Maciej Henneberg (from the Department of Anatomical Sciences, Medical School, University of Adelaide, Adelaide 5005, Australia; the same University, therefore, where Morwood and Brown work) and Alan Thorne (from the Research School of Pacific and Asian Studies, Australia National University, Canberra, ACT 0200 Australia) insisted from the beginning that, in their opinion, what had been found in reality were individuals that belonged to our same species but that presented pathologies. So Homo floresiensis was, in fact, a Homo sapiens with anomalies in the growth, as they announced in a small speech entitled precisely: Flores human may be pathological Homo sapiens * (10). According to these scientists, the most plausible explanation for the small brain size would be microcephaly. So we would be looking at members of our species who would have suffered from some kind of growth pathology subject . In fact, the two scientists cite one of the findings of Liang Bua's team researcher as a fact in their favour. It is a radius, a bone of the forearm, found in the cave and which has a length of 210 mm, which according to Henneberg and Thorne would be equivalent to an individual of between 1.51 and 1.62 metres in height; parameters that fall within the range of variability of Homo sapiens. This is reinforced by the fact that in another cave on the island of Flores, Liang Toge, another skeleton of a Homo sapiens was found that lived 3,500 years ago and was 1.48 metres tall, although its brain capacity was 1204 cc* (11).

The text in which these two scientists express their criticism ends by appealing for caution and warning that until new reasonably complete skulls appear, the hypothesis that a relatively common pathology, such as microcephaly, could be the cause of the morphology discovered in Liang Bua cannot be ruled out.

Brown and Morwood's rejoinder was forceful, perhaps too forceful, going as far as ad hominem argumentation. What was devastating was the content of the counter-critique. Indeed, the co-directors of Liang Bua's work claimed to possess human remains corresponding to seven different individuals, all of them coming from the same cave and all with the same body, dental and facial proportions as specimen LB 1. The authors of the reply ask, quite sensibly, if there is any possibility that all these individuals are a set of sickly types. The answer is that this is highly unlikely, especially considering that we are dealing with a minimal issue of individuals corresponding to a chronological range spanning several tens of thousands of years. To reinforce their position, Brown and Morwood cite one of the jaws found and point out that it lacks a chin* (12), a distinctive feature of Homo sapiens, since this is a morphological characteristic unique to our species. Indeed, no other human species has a chin. Thus, the individual to whom this jaw corresponded must have had two abnormalities: no chin and dwarfism; in the same way that the female of Liang Bua also had two pathologies: microcephaly and dwarfism. In short, too many coincidences together. It was too improbable that every time they found an individual in Liang Bua it was a sick subject that had ended up there, bearing in mind, moreover, that they were thousands of years apart.

Marta Mirazón Lahr and Robert Foley, from the Leverhulme Center for Evolutionary Studies, Department of Biological Anthropology, Cambridge, also think that it is impossible for Homo floresiensis to be a pygmy Homo sapiens. According to these researchers, if we compare the skull of LB 1 with that of a scaled-up present-day human (i.e. at a third of its normal size), it turns out that both differ in shape, robustness and a whole series of key features of the base of the skull. In short, they have no specific similarity * (13).

As for the radius mentioned by Henneberg and Thorne, Morwood and colleagues maintain that it would belong to an individual no more than one metre long and that is why they assign it, provisionally, to Homo floresiensis; but they recognise that, as the postcranial remains assigned to LB 1 lack arms, they cannot make a direct comparison between both * (14), something that will be corrected later on, as we will have the opportunity to check.

Technology too advanced

Another criticism received is the one related to the affirmation of the directors of Liang Bua that the lithic industry found there and associated to a premolar of Homo floresiensis as well as to the remains of Stegodon, was made by this species; which would demonstrate that, in spite of the small size of their brain (let's remember that when the finding was announced, their endocranial capacity was estimated in 380 cc.) they were very intelligent and extremely skilled in the manufacture of complex tools, as much as the Homo sapiens themselves. However, among the archaeological remains, there is nothing comparable to pieces that can be interpreted as art objects.

Tim Reynolds was one of the first to express his doubts regarding the attribution of this technology to Homo floresiensis in the absence of more evident testimonies. Well, for this researcher the morphology of the lithic industry of Liang Bua is similar to the one found in other places of the same geographical area and associated to Homo sapiens; so, if H. floresiensis was the author of the tools of Liang Bua we would have to postulate a parallel evolution of the development technology in that area, something very improbable, so it is more convincing and conservative to think that the artefacts of Liang Bua were made by members of our species * (15).

Morwood and Brown's reply is quite simple. The authors begin by recognising that, indeed, they have not found an unequivocal association of a rich accumulation of lithic industry next to a good issue of fossil remains of Homo floresiensis, but that the association is in that sense weak, as it has already been pointed out above. True, but there is an interesting fact: Many of these tools appear in sediments 78 kyr. old. We know that the oldest remains of H. sapien found to date in Flores are about 12 kyr. old, so he must not have been the maker of these tools. Who then was the maker of these tools, tools so similar to those made at that time by the Neanderthals in Europe and the Sapiens in Africa? At that time there was no way of knowing for sure.

However, Reynolds' argument ends with some very interesting words that we wanted to highlight in addition to what was said in the previous paragraph. In fact, Reynolds recalls that the oldest tools found in Flores are the ones we have already mentioned and which come from Mata Menge, with an antiquity between 880,000 and 800,000 years; according to Reynolds, these tools do not resemble the morphological patterns identified in Liang Bua and there is an enormous time lapse between one and the other.

This is precisely what Morwood's team has been able to clarify from Mata Menge. In fact, there Mark Moore, from the University of New England, and Adam Brumm, from the Australian National University, have found some tools that are 840,000 years old and bear a great resemblance (along with some differences) to those found in Liang Bua. The complexity of these ancient tools shows that Homo floresiensis, much more modern than the authors of those pieces, could well have been the makers of the ones found in Liang Bua. If 800.000 years ago some humans who inhabited Flores (we do not know who, although it is supposed to be some population of Homo erectus) could make tools so similar to the ones found in Liang Bua with a minimum antiquity of between 78 kys. and 18 kys. why could not be Homo floresiensis the maker of these last ones? Alleging that the reason is because they look too modern is no longer a sufficient reason to discard the H. floresiensis as possible authors. An argumentation like this subject would be a form of ethnocentrism.

The bones of discord

Criticism aside, for the time being, a legal battle for possession of the fossils found at Liang Bua has been raging. Teuko Jacob from position of laboratory of Bioanthropology and Palaeoanthropology at Gadjah Mada University in Indonesia initially took possession of the fossils for an initial analysis. He kept them in early November thanks to the partnership of his friend Radien P. Soejono (of the Indonesian Archaeological Centre in Jakarta, who had also been part of the team working at Liang Bua), but on the condition that they had to be returned by 1 January 2005. But he delayed the deadline of submission to the team led by the Australian researchers, so that nervousness and suspicions began to spread that Jacob might end up not allowing their discoverers to analyse them on the grounds that they were the property of the Indonesian government and that their conservation and preservation required that they not be handled too much. In short, a fierce struggle broke out over the right to study the original fossils discovered in Liang Bua* (16); which, moreover, intensified from the moment Teuko Jacob began to say publicly that the remains of Liang Bua were pygmies of our own species, an opinion shared by Soejono, Henneberg, Thorne and Eckhardt* (17).

At the end of March Jacob returned some of the fossils to Morwood and Brown's team. But then came an unpleasant surprise. Some of the returned fossils were in very bad condition, as can be seen in some photos published on 22 March 2005 by the newspaper USA Today* (18). They show the state of the pelvis and jaw before going to Jacob's laboratory and on their return to the custody of Morwood and Brown. The deterioration is clearly visible in both cases, although in the case of the pelvis, the degradation is quite obvious, as it was returned broken. The mandible did not fare much better: the maxilla was missing an incisor; the lower jaw was fragmented in several places (the reconstruction has inevitably changed the physiognomy of this maxillary area); the upper rear part of the upper jaw is missing a fragment of bone; and an empty space, previously non-existent, has been created between the canine and the premolar. In short, something incomprehensible in the case of fossils of such great scientific value * (19).

Computed tomography (CT) analysis of the skull of LB 1

 

In the midst of all this controversy that same month (March 2007), a article by Dean Falk (from the department of Anthropology of the Florida State University) and others* (20) appeared, in which they presented the conclusions of their study on the skull of LB 1. The team led by Falk had analysed the skull of the female "Hobbit" using computerised tomography. The conclusions they reached were that the three-dimensional analysis of the skull of LB1 revealed that it does not have the endocranial structure of a microencephalon, but manifests a normal endocranial structure, only with very tiny dimensions.

In terms of endocranial volume, there was also news. Indeed, as mentioned above, when "Hobbit" was presented to society in October 2004, it was estimated to have a brain volume of 380 cc; a volume identical to that of the average chimpanzee today, and far from the 1350 cc of average of today's humans. The new volume attributed by Falk's team at work was 417 cc.* (21). This brain capacity includes him within the characteristic parameters of the gracile Australopithecus of 3 million years ago, as is the case of Lucy.

But what struck Falk's team most was the structure of the brain. According to them, what they had in their hands was a specimen with the cranial size of an australopithecine but with a distinctly human brain structure.

The way to determine the brain structure of the LB1 skull was from the marks left by the brain on the inner side of the skull. Although the brain, of course, does not fossilise, what it does do is leave the marks of its external structure on the walls of the endocranium.

The study of the endocranium of the Liang Bua hominid has revealed several very important things. On the one hand, it has revealed that the temporal lobes were highly developed; in other words, the areas that in our genus are associated with language comprehension and in which we find Wernicke's area and Broca's area , both closely linked to linguistic abilities. In the temporal lobes there is also the cerebral area that controls hearing.

The researchers also found that the frontal lobe, where Brodmann's area 10 is located, which is the area associated with the control of rational abilities and future planning, was highly developed; the latter characteristic seems to be essentially associated in a way that is unique to the human race.

These data allowed Falk and colleagues to speculate on the possibility that Homo floresiensis was capable of planning complex future actions, as well as mastering some form of spoken language.

Criticisms and counter-criticisms of Falk and colleagues' article

This study sparked a crossfire between several teams at research that lasted throughout the autumn of that year and the beginning of 2006. The first criticisms came from Jochen Weber ( department of Neurosurgery at the Leopoldina Hospital in Schweinfurt, Germany), Alfred Czarnetzki ( department of Palaeoanthropology and Osteology at the University of Tübingen, Germany) and Castren M. Pusch ( of Anthropology and Human also at the University of Tübingen, Germany). Pusch (of the high school of Anthropology and Human Genetics also of the University of Tübingen) when they published a article * (22) in October 2005, just a year after the advertisement of the finding of these very strange humans, in which they denied that the H. floresiensis were members of a species different from ours.

According to these researchers, after analysing 19 microcephalics of our species, they found that their average cranial volume was 404 cc., so that the 417 cc. assigned to LB 1 by Falk's team was within the range of variability of microcephalics of our species. Among the 19 specimens analysed by Weber et al. there was one that caught their attention and on which they focused most of their attention, as it had an endocranial volume of 415 cc; very similar, then, to that of LB 1. After studying six defining characteristics of it, they observed that they were similar to those present in the skull of LB 1. The conclusion they reached is that both the skull and the brain morphology of the 19 microcephalic individuals studied is very similar to the shape of the skull and the structure of the brain of Homo floresiensis, so they rejected that it was a human species different from us and they opted for the hypothesis that affirms that they were pathological individuals of our species.

Regarding the comment of the expectations produced by the drawing of the area 10 in the endocranium of LB 1, Weber et al. denied that it could be something significant about the speculations that were made about the supposed advanced cognitive abilities of the H. floresiensis. According to Weber and his colleagues a microcephalic baron individual studied by them had an endocranial volume of 485 cc. and had a well developed area 10; however, although he was able to walk he could not articulate words. They conclude that extrapolating advanced cognitive abilities to LB 1 from the acceptable size of his area 10 was a leap in the dark.

The reply of Falk et. al. * (23) 

To begin with, Falk's team pointed out that Weber and colleagues were wrong in their calculations of the six features they studied in a microcephalic brain of similar size to that of LB 1, so their calculations are invalid for extrapolation or comparison with the skull of the Liang Bua female. They also note that the images provided by Weber and colleagues in their article are not sufficiently enlightening and may even belong to different individuals. They are also not happy with the reflections made on Bordmann's area 10. In final, they find that important data is missing in the report of Weber and colleagues, so that their thesis regarding the invalidity of the hypothesis that Homo floresiensis is a species different from ours is not conclusive.

New criticisms

7 months after the appearance of these two articles in Nature, the prestigious journal Science published a new critique of the study that Falk's team had done on the skull of LB 1. However, we must point out that the article had been received by the journal on October 11th, 2005, that is, shortly before the appearance of the article by Weber et al. in Nature, as well as the reply by Dean Falk et al. in the same journal. This qualification is important because at the same time that all this cross-statement was taking place, M. Morwood and his collaborators published a article in which they announced new discoveries, making the publication by Science of Martin's commentary a little obsolete in the light of the new findings. But let's not get ahead of ourselves. First we will look at the argumentation of Martin and collaborators, as well as the due rejoinder of Falk's team, and then we will move on to the study of the new findings.

The critique by Robert Martin and co-workers* (24) re-emphasised the idea that the small brain size of the Liang Bua female was not due to a tendency towards dwarfism suffered by a population of Homo erectus under conditions of insularity giving rise to a new human species, but to an encephalopathy of members of our own species.

Finally, the usual thesis which states that the Liang Bua specimens were sick Homo sapiens, specifically suffering from microcephaly. A disease to which, remember, we must add that of dwarfism and the craniofacial anomaly of the lack of a chin. In short: too many pathologies in the same individual and the same fossil sample .

Martin and co-workers note that the "European microcephalic" specimen* (25) used in the Falk team's study is actually a plaster cast of a skull and not the original fossil, adding that the calotte did not fit well with the rest of the cast because it was varnished. In fact, according to Martin and colleagues, the spectrometric study confirmed that the calotte belonged to a different batch of plaster than the craniofacial structure.

Martin and colleagues also report that Falk and colleagues are only aware of one subject of microcephaly and not the many variations of this disease, more than 400, which makes the available skulls of microcephalic individuals highly variable, always associated with genetic malformations. According to Martin and colleagues, given that there are more than a dozen diseases associated with growth retardation syndromes and microcephaly, LB 1 could very well be an individual born to normal-sized humans.

Martin's article ends by stating that the tools found at Liang Bua have a morphology more closely associated with Homo sapiens than with Homo erectus.

Falk et al's replication * (26) 

To begin with, Falk's team rejects that the two microcephalic skulls in Martin's team's possession, which they claim to be very similar to LB 1, are in fact similar. According to Falk there are a number of important features that do not match. They also warn that many data (such as comparative measurements, real photographs - in Martin's articles there are only drawings - and identifying sketches of the most important features) are missing in order to draw meaningful conclusions from Martin and collaborators' study.

Falk also denies that they are unaware of the wide variety of genetic syndromes associated with primary microcephaly, contrasting the view of Martin's team that the typical pathology is autosomal recessive inheritance, which Falk says conflicts with what they have found in the literature.

Falk insists that Martin's statements about two endocraniums which would be similar to the one of Liang Bua lack data crucial to be able to determine the real Degree of similarity and therefore they cannot be taken into account when accepting or refuting one of the hypotheses about the status of Homo floresiensis.

As for Martin's team's assertion concerning the Liang Bua tools, Moore and Brumm's work on the tools discovered at Mata Menge, as we shall see below, renders this argument invalid.

New discoveries

At the same time that all this series of crossed declarations were taking place in October 2005, although some were published in May 2006, Mike Morwood's team announced that it had found more remains of Homo floresiensis, publishing a work on the study of some fossils that still remained unpublished * (27).

The new material described comprises fossils that corresponded to a three-year-old child measuring about 50 cm, and to an adult that was even shorter than in Liang Bua specimen 1. These fossils include a new mandible belonging to an adult individual, and postcranial remains from several specimens, as well as the arm bones of LB1, which were not originally found in 2003, and which therefore allow comparisons to be made with other arm bones belonging to other individuals. In fact Morwood declares that the new material can already reconstruct the body proportions of H. floresiensis with a high degree of certainty, so that it can be confirmed that the morphology of these specimens was a specific characteristic and not an aberrant form resulting from some individual pathology subject .

Their discoverers considered that the fossils found had an antiquity that spanned a chronological range from twelve thousand years (the date calculated for their extinction before the first humans of our species arrived on the island, at least this is what is assumed for the moment) to ninety thousand years for the oldest specimens.

The conclusions drawn by Morwood and Brown from the new findings were resounding. The evidence was mounting in favour of thesis that we are dealing with a new human species that managed to survive until just 12,000 years ago. The Flores men were humans who did not belong to our species. The fact that all the bones found have proportionally small dimensions would prove that the partial skeleton of a woman found in Liang Bua was not a dwarf woman, but that we are dealing with a human species that is really different from ours; and that presents, as the most relevant morphological characteristic, a diminutive stature.

Logically, the duplication of fossil bones reinforces the idea that H. floresiensis corresponds to a population of tiny humans specifically different from any other human subject ; thus ruling out the possibility that the LB1 skeleton represented an individual affected by a pathology (or several at the same time, as required by the contrary thesis ) or that it was some anatomically aberrant form of sapiens.

Among the new discoveries announced is a tibia whose size suggests that the individual it belonged to was no taller than 106 cm, which, for the moment, would be the tallest specimen of Homo floresiensis ever found.

The article concludes by stating that the origin of Homo floresiensis is still uncertain, but that it can no longer be said that it was a simple allometric version of Homo erectus; that is to say, that the H. floresiensis do not descend from a population of H. erectus that arrived on the island and reduced in size.

The lithic industry of Mata Menge * (28) 

We have referred on several occasions to the publication of a work on the finding of stone tools at the Mata Menge site, some 50 km from Liang Bua, with a maximum age of between 800,000 and 880,000 years. The collection comprises just over 500 small pieces and a comparison with those found at Liang Bua, which range in age from 95,000 to 12,000 years, shows a striking morphological and functional similarity in most of them.

One of the arguments that had been put forward to deny that Homo floresiensis was the author of the lithic industry found in the cave of Liang Bua was that its appearance was too modern, so that it appeared to be the product of Homo sapiens rather than the result of a manufacture by tiny humans with a brain the size of a grapefruit.

The defenders of the idea that it was Homo floresiensis who had made those tools had against them the fact that there were hardly any fossils of this species next to the lithic industry. But those who affirmed that the authorship was of Homo sapiens did not provide more convincing reasoning either, since the oldest remains of anatomically modern humans found in Flores are less than 12 kyr. old, while there are morphologically modern tools in Liang Bua which were carved 95 kyr. ago.

The fact of having discovered in Mata Menge a collection of tools made more than 800 kyr. ago with an aspect as modern as most of the ones discovered in Liang Bua, means that it cannot be ruled out that Homo floresiensis was the author of the latter. However, this does not automatically mean that he was, but simply that it is no longer possible to say that it was impossible for him to have made them because their appearance is too modern and only Homo sapiens can carve tools with such a complex morphology. 800,000 years ago, it is not that Homo sapiens had not reached Flores, it is that they did not even exist as a species. However, as there are no human remains associated to the collection of Mata Menge, it is not possible to affirm who was its maker, nevertheless the best candidate is Homo erectus for being the only taxon known in the area at that time. However, as we will see later on, other possible authors, as yet undiscovered, cannot be ruled out.

Brumm and Moore conclude their article remembering that Homo floresiensis disappeared 12 kyr. ago, while the oldest burials of Homo sapiens found in Flores are 10.500 years old and show a radical behavioural change with respect to all the previous ones, including the archaeological record related to the lithic industry. Finally, and in the absence of evidence to the contrary, Brumm and Moore maintain that the most logical interpretation is to suppose that the set of tools found in Mata Menge and Liang Bua represent a technological continuity carried out by the same hominid lineage. To affirm that Homo floresiensis lacked the brain size to make such tools would be based more on prejudices than on real evidence.

The most recent criticisms

When the summer of 2006 was coming to an end, new criticisms appeared regarding the status of Homo floresiensis understood as a human species with its own entity. Teuko Jacob, Radien P. Soejono, Maciej Henneberg, Allan Thorne, R. B. Eckhardt et al. were the ones who signed a article * (29) in which they defended again that the human remains found in Liang Bua were of Homo sapiens who had suffered several pathologies.

According to these authors, the specimens found in Liang Bua come from a population of pygmy Homo sapiens, ancestors of the Rampasasa that currently inhabit the region. According to these researchers, the individuals found in the Flores cave show individual signs of an abnormal development , including microcephaly.

It could be argued that this is unlikely as it would imply that these individuals must have been dwarf, microcephalic pygmies, which would mean that they had suffered from too many pathologies together. However, the authors counter that microcephaly is commonly accompanied by a number of other abnormalities* (30).

We said above that the jaw of LB 1 lacked a chin* (31), something that contrasted with the morphology of Homo sapiens. However, Teuko and colleagues argue that 93.4% of present-day Rampasasa pygmies have a neutral or negative chin, i.e., either a very slight chin or no chin at all, and the jaw is sample receding (i.e., with a slight backward slant) in that area.

New data on the skull of LB 1

That same month of September, another article about Homo floresiensis appeared in the Journal of Human Evolution * (32). In it, its authors argued that the skull of LB 1 was not that of a microcephalic individual, but that it corresponded to a healthy individual of diminutive size. This was in favour of those who consider Homo floresiensis as a human species different from ours. The authors reached this conclusion after having studied the skull of LB 1 and compared it with that of the first humans, two skulls of microcephalics, a skull of a pygmy extracted from another cave in Flores, several skulls of Homo sapiens (which included those of some African pygmies and those of individuals from the Andaman Islands -in the Indian Ocean, Australopithecus and Paranthropus, concluding that it is very unlikely that LB 1 is a microcerphalic human, nor attributable to any other known species, so it is reasonable to assign it to a new human species: Homo floresiensis. The article ends by addressing the topic of the origin of these amazing humans, a question we will deal with later on.

Brain shape in microcephalic humans and in Homo floresiensis

 

The year 2007 has seen the appearance of new works on Homo floresiensis. In February Falk's team published a article in the Proceedings of the National Academy of Sciences (PNAS) * (33) in which they reiterated from new programs of study that the specimen nº 1 of Liang Bua could not be a microcephalic Homo sapiens. To this end, they have reconstructed in three dimensions, using computerised tomography, the endocraniums of 9 microcephalic and 10 normal humans. These virtual reconstructions pick up the marks left by the brain on the internal walls of the endocranium, so that the external morphology of the brain is reflected; it also makes it possible to calculate the cranial capacity.

As the cranial capacity of Homo floresiensis is only 417 cc., some researchers have suggested that it is a microcephalic Homo sapiens rather than an individual of a new human species. This hypothesis is difficult to assess without a clear understanding of how the brain shape of microcephalics compares to normal humans. The team led by Dean Falk and Mike Morwood, using computed tomography, has made three-dimensional reconstructions of three endocraniums.

From the observations made on these casts, the researchers were able to identify two variables that allow the brain to be classified as normal and microcephalic with 100% accuracy. From these data the team of Falk and his colleagues have been able to conclude that the resemblance of LB1 is more similar to that of a normal brain than to that of a microcephalic brain. According to the authors, their research not only allows them to classify the LB1 brain as normal, rather than microcephalic, but also provides data on the genetic substrate of human brain evolution and can be of great service to clinical diagnosis.

However, despite the fact that the brain of LB1 sample resembles a normal human rather than a microcephalic one, there are also a series of characteristics, such as its small brain size, which are consistent with attributing it to a human species of its own, i.e., different from ours.

Microcephaly, the possession of an unhealthily small brain, is a condition whereby adults reach brain masses of around 400-500g, resulting in moderate to severe mental retardation. Case studies of microcephalic individuals from all over the world have been reported on research . The disease is usually the result of consanguineous unions.

Due to the controversy surrounding the status of LB 1, the authors of research have decided to study the endocranium of a microcephalic female with a similar cranial volume to the tiny female from the island of Flores. They have also studied the skull of another adult microcephalic female which, in addition, average is approximately the same as the Flores female.

Virtual endocraniums were electronically measured to obtain the cranial capacities traditionally used to express brain mass. The difference in brain size between immature microcephalics and normal humans was found to be smaller than the values assigned to mature microcephalics. This is because in these pathological individuals their maximum brain development is reached earlier than in normal humans. From this point onwards, the brain of microcephalics decreases in size.

The conclusion of the study is that the skull of LB 1 sample has more issue features similar to those of a normal person (except for its size) than those of a microcephalic person.

The study of the lithic industry of Southeast Asia

In another work Mark Moore and Adam Brumm re-examine the current understanding of Pleistocene lithic artefact collections in Southeast Asia* (34). Naturally, despite such an aseptic degree scroll , this work has to be framed within the controversial discussion that arose around the hominid status of Homo floresiensis. The already mentioned finding in Mata Menge of some stone tools more than 800 kyr. old and with a morphology similar to that of the lithic industry associated to H. floresiensis, demolishes the preconceived idea that only humans of our species can be the authors of lithic instruments of such an advanced typology. In this new article Moore and Brumm go deeper into the issues dealt with in the article published in Nature in June 2006.

According to the authors, a distinction has long been made between collections of large lithic industry (tool cores) and small lithic industry (flakes). The former are usually associated with H. erectus, while the latter are assigned to H. sapiens. The authors argue that this traditional way of interpreting the Southeast Asian archaeological record in relation to lithic industry assumes that artefacts recovered from a site reflect a complete technological sequence. Following the analysis of the Pleistocene artefact collections found at Flores, the authors argue thesis that the long pebble cores and small flakes are aspects of a single reduced sequence.

Moore and Brumm propose to apply the model observed on Flores to the study of Pleistocene artefacts from other islands in that geographical area . The article concludes by discussing the implications of this way of analysing the Southeast Asian archaeological record for establishing associations between lithic artefact collections and human species on Southeast Asian islands.

The structure of the shoulder of Homo floresiensis.

For the moment, the last of the main articles that have been published about Homo floresiensis, is one by Susan G. Larson's team concerning the structure of its shoulder * (35) and which appeared in August.

The authors of the study suggest that the shoulder joint of the Homo floresiensis did not have a similar structure to that of the anatomically modern humans; that is, us. In their opinion, the clavicle is relatively short compared to ours (taking into account its smaller absolute size) and the scapula was longer, which would make the movements more anterior than lateral. Overall, the morphology of the shoulder more closely resembles that of the Nariokotome Boy, or Turkana Boy, a specimen of African Homo ergaster or Homo erectus, technically known as KNM-WT 15000, found by Richard Leakey and Allan Walker's team in Kenya in 1984. After comparing the homologous bones of LB 1 with the right clavicle of the Nariokotome Boy (KNM-WT 15000 D), the scapula (KNM-WT 15000 E) and the humerus (KNM-WT 15000 F) the authors of the study conclude that the configuration of the shoulder of Homo floresiensis could suppose a transition between the one shown by the morph represented by the Turkana Boy and Homo sapiens, so that, while our shoulder is more susceptible to lateral movement the one of the H. floresiensis would be more adapted to frontal than lateral movement.

In spite of the evident differences between the physiognomy of the Homo erectus represented by the Child of Nariokotome and that of the H. floresiensis, shown by the partial skeleton of Liang Bua, it must be recognised that the set formed by the bones which form the shoulder are closely related (relatively short clavicle, low Huaraz torsion index, etc...). That is why Susan G. Larson and colleagues consider that these similarities do not correspond to casual morphological coincidences, but are part of the expression of a functional complex which had characterised the early Homo erectus and which was conserved by Homo floresiensis. It would therefore be an evolutionary development that had remained unknown until now. Finally, the authors turn their gaze to Dmanisi (Republic of Georgia) and warn that the new discoveries of postcranial remains made in the Caucasian site (which, curiously, they do not assign to Homo georgicus, but to an early Homo erectus from the Caucasus) could shed light on the matter.

The structure of the wrist of Homo floresiensis

A month after the appearance of the article on the shoulder of Homo floresiensis, the magazine Science published a new study about another element of the postcranial skeleton of this human species. This time it was a work of research on the wrist of the LB 1 skeleton carried out by the team led by Matthew W. Tocheri (from the department of Anthropology of the National Museum of Natural History of the Smithsonian Institution of Washington) * (36).

The conclusions reached by the study are very similar to those established after analysing the shoulder of this same skeleton and comparing it with that of the Nariokotome Child. The archaic morphology of the three wrist bones analysed confirms that they are not at all similar to ours, but rather they seem to represent a morphology dating back to more than 800,000 years ago, which means that the Anatomy of the wrist of Homo floresiensis is not present either in Homo sapiens, Homo neanderthalensis or even in the last common ancestor of both.

The morphology of the wrist of the H. sapiens and the neanderthals present some derived characters which are not in the one of LB 1. From these programs of study the authors conclude that Homo floresiensis is not a pathological Homo sapiens, but an own human species, different from all that can be found in the fossil register of the human genus. According to Tochieri and his colleagues, Homo floresiensis branched out constituting its own evolutionary pathway before the lineage that led to the sapiens and neanderthals from their last common ancestor was produced.

The authors acknowledge, however, that more fossils are needed, especially of Homo erectus in the broad sense, i.e. African specimens between 1.8 and 1 Ma. They are mainly missing carpal bones* (37) from this clade. If they could be found, they would significantly help to validate or refute the hypothesis put forward by the authors.

The uncertainty of the origin of Homo floresiensis

What is the origin of Homo floresiensis? The topic is very open, as it involves many uncertainties. At the beginning, its discoverers were firm believers that the H. floresiensis were descendants of the Homo erectus, which would have arrived in what today is Java and Sumatra 1.8 million years ago (as the findings of Modjokerto, Trinil or Solo indicate, and according to the dating of the geochronologist Carl Shiwcher). We have already said that Flores was never connected to the mainland because it was always isolated by an arm of the sea that acted (relatively) as a biological barrier. This separation is known as "Wallace's Line". Human presence on Flores dates back at least 800,000 years, Morwood argues, claiming that this is indicated by the fact that lithic tools have been found on the island at that age. However, there are those who question this, arguing that their morphology is not of anthropogenic origin, but the result of the action of natural agents. However, the truth is that most of the academic community tends to give credit to the testimony of Morwood and Brown. The question would then be: How was it possible for humans to navigate such dangerous waters 800,000 years ago? Did they land on Flores by chance? In any case, this fact is part of one of the many enigmas that remain to be solved in relation to the human presence in Flores.

There are currently three main hypotheses to explain the origin of Homo floresiensis. On the one hand, there is the possibility that they are the descendants of some supposed erectus that would have arrived in Flores at least 800,000 years ago (being the possible authors of the tools found in the depression of Soa), and that they would have reduced their body dimensions as a means of adaptation to the scarce resources of the island. This was the hypothesis favoured until now by the authors of finding. Another possibility is that the H. floresiensis already arrived on the island with a significantly diminutive size, perhaps as a result of a process of dwarfism undertaken on other islands. This is currently the hypothesis considered most plausible by the directors of the team carrying out the work on Liang Bua. Although, in this case, the question remains as to which species the H. floresiensis would have evolved from. However, it cannot be ruled out that these humans already arrived with extremely tiny body dimensions in Southeast Asia before occupying any island. In such a case, the possibility that they were directly descended from Homo habilis, or Homo georgicus, seems plausible. Not surprisingly, since the Dmanisi finds in the Caucasus, it has been demonstrated that the first humans to leave Africa were not Homo ergaster (i.e. the so-called Homo erectusafricans; or, to be more precise, the African ancestors of the Asian Homo erectus) but a more archaic human species, possibly derived from Homo habilis: Homo georgicus* (38). More surprising is the proposal of Milford Wolpof, who suggests that the H. floresiensis could descend from the Australopithecus and that even these could have left Africa, being the architects of an early exodus towards Southeast Asia. Such a risky proposal would have to be based on minimally solid empirical evidence (some fossils that could suggest something like this) in order to have a certain margin of credibility. However, nothing of the sort has been found, although Wolpof argues that it has happened, we just don't know how to see it, so that fossils hitherto ascribed first to Meganthropus and then to H. erectus would have to be re-examined in the light of the new findings to see if it was possible to ascribe them to Australopithecus. A proposal which is too heterodox and which, before acquiring any credibility, must see how the possibilities of more plausible and less revolutionary hypotheses are exhausted.

Be that as it may, the mystery of the origin of H. floresiensis remains.

Notes

1. Cf. P. Brown, M.J. Morwood, et al.: A new small-bodied hominin from the late Pleistocene of Flores, Indonesia; Nature, 431, 28 October 2004, pp. 1055-1061; and M.J. Morwood, R.G. Roberts, et al.: Archaeology and age of a new hominin from Flores in eastern Indonesia; Nature 431, 28 October 2005, pp. 1087-1091.
2. A tiny island in the Indonesian archipelago between Java (to the west) and Timor (to the east), with Australia to the south and the Celebes and the Maluku Islands to the north.
3. Some have reminded us, not without a certain amount of humour, that despite being called Homo floresiensis, we must not forget that the holotype (or paradigmatic specimen of the clade) is a female; technically known as LB 1.
4.  Refers to 28 October 2004.
5. http://www.portalciencia.net/antroevoflor.html
6. M.J. Morwood et al.: Fission-track ages of stone tools and fossils of the east Indonesian islands of Flores; Nature 392, pp. 173-176, 1998. And M. J. Morwood et al.: Archaeological and paleontological research in central Flores, east Indonesia: results of fieldwork, 1997-98; Antiquity 73, 273-286 (1999).
7. Kyr. It means kylia years, i.e. thousands of years.
8. For an exhaustive analysis of the most important aspects related to the finding of Homo floresiensis see Carlos A. Marmelada: Homo floresiensis. El pequeño gran misterio de la evolución humana; athttp://www.unav.es/cryf/homofloresiensis.html, this is the text of a lecture given on 19 April 2005 at the Cardenal Herrera University of Valencia; also at the virtual portal of the Regional Ministry of Education and Culture of the Government of the Autonomous Region of Murcia (Portal educational de la Región de Murcia). See also Carlos A. Marmelada: El pequeño gran hombre de Flores; Aceprensa service 144/04, 10-11-2004.
9. They are also popularly named after J.R.R. Tolkien and his race of tiny humans in the Lord of the Rings Saga.
10. article included in Larry Barham: Some initial informal reactions to publication of the discovery of Homo floresiensis and replies from Brown & Morwood; in Before Farming 2004/4 article 1, pp. 2 and 3. The reply from Brown and Morwood is on p. 6.
11. This skeleton was described by Teuko Jacob in: Some problems pertaining to the racial History of the Indonesian Region; Utrecht: Drukkerij, Neerlandia, 1967.
12. We will come back to this later. See below at grade 31.
13. M. Mirazón Lahr and R. Foley: Human evolution writ small; Nature, vol. 431, 28 October 2004, p. 1043.
14. M.J. Morwood et al.: Archaeology and age of a new hominin from Flores in eastern Indonesia; op. cit., p. 1089.
15. View expressed by Tim Reynolds in Larry Barham: Some initial informal reactions to publication of the discovery of Homo floresiensis and replies from Brown & Morwood; in Before Farming 2004/4 article 1, pp. 4 and 5.
16. For more information on topic see Elizabeth Culotta: Battle erupts over the 'Hobbit' bones; Science, Vol. 307, 25 February 2005, p. 1179.
17. See Rex Dalton: Fossil finders in tug of war over analysis of hobbit bones; Nature, Vol. 434, 3 March 2005.
18. We cannot but thank M. J. Morwood for his great kindness in providing us with a copy of the pages of this diary.
19. For an analysis of the state in which the H. floresiensis fossils were returned to M. Morwood and colleagues see Elizabeth Culotta: Discoverers charge damage to 'Hobbit' specimens, Science, 25 March.
20. Dean Falk, Charles Hildebolt, Kira Smith, Mike Morwood, Peter Brown, et al.: The brian of LB1, Homo floresiensis; Science Express, and Science, Vol. 308, pp. 242 ff. Cf. also, Michael Balter: Small but smart? Flores hominid shows signs of advanced brain; Science 307, 4 March 2005, pp. 1386-1389. And also Carlos A. Marmelada: El Hombre de Flores asombra a los científicos, Aceprensa, Servicio 27/05, 09-03-2005. Also see Rex Dalton: Looking for the ancestors; Nature, Vol 434, 24 March 2005, pp. 432-434.
21. Data calculated from a virtual reconstruction of the skull using computed tomography (CT) techniques.
22. J. Weber, A. Czarnetzki and C. M. Pusch: Comment on "The brian of LB 1, Homo floresiensis; Science, Vol 310, 14 October 2005, p. 236b.
23. D. Falk et al.: Response to Comment on " The Brian of LB 1, Homo floresiensis "; Nature, Vol. 310, 14 October 2005, p. 236c.
24. Robert D. Martin et al.: Comment on "The Brian of LB 1, Homo floresiensis"; Science, Vol. 312, 19 May 2006, p. 999b.
25. Technically known as AMNH 2792nd and corresponding to a boy named Jacob Moegele, who died at the age of 10 in Plattenhardt, Germany. His cranial capacity was very tiny indeed: 272 cc. The acronym AMNH stands for American Museum of Natural History.
26. Dean Falk et al.: Response to Comment on " The Brian of LB 1, Homo floresiensis "; Science, Vol. 312, 19 May 2006, p. 999b.
27. M. J. Morwood et al.: Further evidence for small-bodied hominins from the Late Pleistocene of Flores, Indonesia; Nature, Vol. 437, 13 October 2005, pp. 1012-1017. Other related articles that can be consulted are Daniel Lieberman:Further fossil finds from Flores; Nature, Vol 437, 13 October 2005, pp. 957-958 and Rex Dalton: More evidence for hobbit unearthed as diggers are refused access to cave; Nature, Vol. 437, 13 October 2005, pp. 934-935; as well as Elizabeth Culotta:New 'Hobbits' bolster species, but origins still a mystery; Science, Vol. 310, 14 October, pp. 208-209.
28. Adam Brumm, Mark Moore, Fachroel Aziz, Michael Morwood, et al.: Early stone technology on Flores and its implications for Homo floresiensis; Nature, Vol. 441, 1 June 2006, pp. 624-628. See also Elizabeth Culotta: Tools link Indonesian 'Hobbits' to earlier Homo ancestor; Science, Vol. 312, 2 June 2006, p. 1239. Also see Michael Hopking: Old tools shed Light on hobbit origins; Nature, Vol. 441, 1 June 2006, p. 559.
29. Teuko Jacob, Rodien P. Soejono, Maciej Henneberg, Allan Thorne, R. B. Eckhardt et al.: Pygmoid australomelanesian Homo sapiensskeletal remains from Liang Bua, Flores: Population affinities and pathological abnormalities; PNAS, Vol. 113, No. 36, 5 September 2006, 13421-13426.
30. Jacob et al.: Pygmoid australomelanesian Homo sapiens skeletal remains from Liang Bua, Flores: Population affinities and pathological abnormalities; op. cit., p. 13.422.
31. See above grade 12.
32. Debbie Argue, Dense Donlon, Colin Groves, Richard Wright: Homo floresiensis: Microcephalic, pygmoid, Australopithecus , or Homo?; Journal of Human Evolution, 51, 2006, pp. 360-374.
33. D. Falk, et al.: Brian shape in human microcephalics and Homo floresiensis; PNAS, Vol. 107, No. 7, 13 February 2007, pp. 2513-2518.
34. M. Moore and A. Brumm: Stone artefacts and hominins in island Southeast Asia: New insights from Flores, eastern Indonesia; Journal of Human Evolution, Vol. 52, 2007, pp. 85-102.
35. S. G. Larson: Homo floresiensis and the evolution of hominin shoulder; Journal of Human Evolution, 2007, pp. 1-14.
36. Matthew W. Tocheri, et al.: The Primitive Wrist of Homo floresiensis and Its Implications for Hominin Evolution; Science, Vol. 317, 21 September 2007, pp. 1743-1745.
37. Scaphoid, lunate, trapezium, trapezoid, trapezoid, etc...
38. For more information on Homo georgicus cif.: Fossils found in the Caucasus are assigned to a new human species; by Carlos A. Marmelada, in Aceprensa service 154/02, 20-11-2002.