New Species of Hominin Found in Phillipines

From a story in UPI:

At the completion of excavations on the island of Luzon, scientists had unearthed several teeth, part of a thigh bone, and a few hand and foot bones. The fossils comprise the "the earliest direct evidence of a human presence in the Philippines," according to the latest study.

The fossilized bones, dated to between 67,000 and 50,000 years ago, feature a mix of anatomical characteristics, some that recall more primitive hominins and others similar to those of more modern human species.

Callao Cave is toward the northern tip of Luzon. The corresponding article from Nature seems to indicate that the fossil remains from this cave are “all over the map.”  The premolars indicate size and shape affinities to later Homo, while some of the characteristics are australopithecine (!).  This is also true of the hand elements. 

Although we have found human fossil remains in East Asia for some time (1896 on), there are large gaps in our knowledge, especially from the first appearance of Homo erectus to the advent of modern humans.  These fossils, while giving us more  information than we had, muddy the waters a bit.  Once upon a time, Grover Kranz (RIP) tried to convince me that australopithecines could be found in East Asia, but his evidence was based on a badly crushed occipital bone. 

It is clear from the presence of H. floresiensis and the current evidence that primitive traits were being retained in some groups but, as the authors point out, we need quite a bit more fossil material to make any definitive assessments. 

Why Is Homo floresiensis Still Such a Mystery?

Cosmos Magazine has an article by Debbie Argue, biological anthropologist from Australian National University, about Homo floresiensis and why it has been a struggle to accurately and adequately place this hominin within the framework of human evolution.

 Here was the initial assessment:

Peter Brown and colleagues originally proposed two competing hypotheses about the origins of H. floresiensis. One is that the species is an early hominin similar to the earliest identified in the Homo genus. The fossils for these species are known only from Africa and are between one and two million years old. This implies that the ancestors of H. floresiensis could have got to Flores Island in the vicinity of a million years ago and survived there until at least 60,000 years ago.

Their alternative hypothesis was that H. floresiensis is a dwarfed descendant of Homo erectus, which is the only known non-sapiens hominin to once have existed in Indonesia. Its remains have been found on the island of Java. According to this view, the dwarfing of H. erectus was an evolutionary response to being isolated on an island with a limited food supply. Just as the Asian elephant evolved into the dwarfed Flores stegodon after becoming marooned on the island, H. erectus could have met a similar fate.

It was also proposed that this hominin might have expressed microcephaly.  This idea failed to explain other aspects of the skeleton, however, such as its diminutive height (around 3 feet), long arms and feet and primitive skull features. Here is an image of H. floresiensis compared to a modern human, who had been running around the landscape for at least 100k years while H. floresiensis was extant.

This all saw at least some resolution with the discovery and description of some remains  on another areas of the island Flores that were very similar to the H. floresiensis remains but dated to some 600 thousand years earlier than the remains in Liang Bu.  This lent more credence to the idea that H. floresiensis was, in fact, an offshoot of Homo erectus.

So, Argue, along with Colin Groves, Bill Jungers and Mike Lee, performed statistical tests (this story does not say which kind, a peculiar omission) on a number of different hominin species, comparing them to H. floresiensis.  What did they find?

We therefore hypothesise that H. floresiensis shared a common ancestor with H. habilis. We do not know who that ancestor was or when it lived, but it would have to be older than the oldest H. habilis specimen known, so older than 1.75 million years. The implication is that the H. floresiensis ancestor evolved before that time in Africa, dispersed from that continent, and arrived on Flores earlier than 700,000 years ago, judging by the age of the jaw and teeth found at Soa Basin. This represents a hitherto unknown movement of very early hominins out of Africa.

Presently, the earliest evidence for hominins outside of Africa come from Europe, the Near East and Asia, and date to between 1.5 and 1.8 million years ago. Argue's hypothesis would suggest that H. floresiensis appearance in east Asia represents a separate migration out of African sometime either before or after the wave that saw Homo erectus show up in Trinil and Sangiran, in Indonesia.

Questions still abound as to why this species never saw the evolutionary trajectory that other hominins went through in terms of cranial expansion, increase in height and changes in brachial and crural indices. On the other hand, if evolution proceeds through what we have termed systematics, then advanced traits will show up in related species and if the ancestors of H. floresiensis were cut off, they would just go on their merry way.  We know that such a pattern holds for H. naledi, in South Africa, which coexisted with archaic Homo sapiens, in some way, shape or form. 

The article ends on a very peculiar note, in which she suggests the remote possibility that H. floresiensis is still alive out there, somewhere:

Could the Hobbit still exist in the wild mountain forests of Flores? When H. floresiensis was announced, the media picked up on the local folklore that small human-like creatures roam the forests. Descriptions of sightings are well recorded and quite detailed. The similarity to H. floresiensis is intriguing. But most researchers would say ‘show me the bones!’

This reminds one of the stories involving the Yeti/Sasquatch/Abominable Snowman, which likely derive from the finding of the bones of the Miocene ape Gigantopithecus, which was close to ten feet tall, when standing.  Is H. floresiensis still out there?  Probably not, but I am sure that the cryptozoologists haven't given up hope. 

Is Homo floresiensis a Sister Species of Homo habilis?

A short blurb in Science Magazine attempts to lay to rest one of the nagging questions in recent human evolution: where did the diminutive “hobbits” originate?  A report by the Australian National University suggests that Homo floresiensis is a sister species of Homo habilis. 

Data from the study concluded there was no evidence for the popular theory that Homo floresiensis evolved from the much larger Homo erectus, the only other early hominid known to have lived in the region with fossils discovered on the Indonesian mainland of Java.

Study leader Dr Debbie Argue of the ANU School of Archaeology & Anthropology, said the results should help put to rest a debate that has been hotly contested ever since Homo floresiensis was discovered.

"The analyses show that on the family tree, Homo floresiensis was likely a sister species of Homo habilis. It means these two shared a common ancestor," Dr Argue said.

"It's possible that Homo floresiensis evolved in Africa and migrated, or the common ancestor moved from Africa then evolved into Homo floresiensis somewhere."

Homo floresiensis is known to have lived on Flores until as recently as 54,000 years ago.

How do we know this?

Where previous research had focused mostly on the skull and lower jaw, this study used 133 data points ranging across the skull, jaws, teeth, arms, legs and shoulders.

Dr Argue said none of the data supported the theory that Homo floresiensis evolved from Homo erectus.

I think that it is passing peculiar that we have found absolutely nothing else like this in over 100 years of searching in this area, but who knows what these smaller islands have hidden in them. This also raises interesting questions. Since we know that early Homo got as far as Russian Georgia, is it possible they got as far as Flores? That's a long way.  Is it possible that incoming Homo erectus out-competed them in most places except for a few small refugia?  Also possible.   Hopefully more information will turn up to help us answer these questions.

H. floresiensis Not As Young or As Unique As We Thought

In other words, so much for the pathology argument.  Many news outlets, National Geographic being one of them, are reporting on new fossils that closely match those of Homo floresiensis that were found at Liang Bua Cave on the island of Flores in the late 1990s.  Adam Hoffman writes:

The 700,000-year-old human remains are the first found outside Liang Bua cave, the site on Flores that yielded the original hobbit fossils. The much older samples show intriguing similarities to H. floresiensis, including their small size, and so provide the best evidence yet of a potential hobbit ancestor.

“Since the hobbit was found, there have been two major hypotheses concerning its ancestry,” says Gerritt van den Bergh, an archaeologist at the University of Wollongong in Australia and a contributor to the work.

According to one theory, H. floresiensis is a dwarfed form of Homo erectus, an ancient human relative that lived in East Asia and parts of Africa until about 143,000 years ago. But other researchers think the hobbits evolved from even earlier, smaller-bodied hominins such as Homo habilis or Australopithecus.

“These new findings suggest that Homo floresiensis is indeed a dwarfed form of Homo erectus from Java, a small group of which must have gotten marooned on Flores and evolved in isolation,” van den Bergh says.

The article goes on to note that the competing argument, that the fossils of Liang Bua represent some kind of pathological condition, and that they maintained this condition for some 700 ky, is now untenable. Clearly this is a side-branch of human evolution.The other key finding is that they also had stone tools, specifically a “straightforward core and flake” technology. Further, the tools show a striking similarity to those found at Liang Bua, suggesting that there was remarkable cognitive "stability" in this population. 

The more we think we know about human evolution, the less, it turns out, that we do.  For now, the entire article is available from Nature for free here. 

A Plea For the Importance of East Asia in Human Origins

In response to the discovery of new archaeological evidence from the island of Sulawesi, the Conversation makes a plea for the role of East Asia in human origins, who argue that eurocentrism and Africacentrism have ruled the roost in hominin research.  The article lays out some of the research that has gone on in the last 150 years or so, ending with the recent discovery and controversy surrounding Homo floresiensis.  The author suggests that we are missing some very important information:

Stone tools and animal fossils dated to between 100,000 and more than 200,000 years old have been found in Walanae Basin of Sulawesi: the oldest archaeology in the island, and showing it was inhabited by a unknown archaic species long before modern humans were on the scene.

Sadly, no human bones were found, so we have no idea who made the tools.

I suspect they were made by a species that we don’t see anywhere else. Not Homo erectus, nor Homo floresiensis, but a novel one. Why?

Sulawesi sits on the eastern edge of the famous biographic zone ‘Wallacea’ - marking the transition from an Asian ecology to an Australasian one - and has a truly remarkable fauna and flora.

It’s also located just to the north of Flores and so was probably on the North-South migration path for many animals including early humans.

The mammals that inhabit Sulawesi today are remarkable for their diversity: of the 127 endemic mammals that inhabit Indonesia, 62 percent are unique to Sulawesi.
Among the primates, there are seven endemic species of the monkey genus Macaca and at least seven Tarsier species probably more.

In my view, the same kinds of evolutionary pressures that led to this remarkable diversity of non-human primates would have acted also on the early humans inhabiting the island.
A couple of hundred thousand years is plenty of time for new species to form.

This is not the first argument to be made for non-existent evidence. That argument has been made variously to explain the transition from one of any number of australopithecines to early Homo and archaeological evidence for Middle Palaeolithic populations in Japan is sitting off the coast of south Japan in several different scenarios.While it is quite interesting to contemplate the peculiarity of the faunal diversity of Sulewesi, it is a far cry to posit a new species responsible for the tools that might be there.  It is quite true that we do not know exactly what is going on with H. floresiensis or the strange island from which it hails, but that does not warrant a separate species.

He is, however, correct that East Asia has often been seen as secondarily important in hominin circles, and the recent discoveries in south China ought to strongly suggest that this is not so. 

Homo floresiensis Gains Legitimacy

Science Daily has posted a story detailing new examination of the Liang Bua crania by researchers at SUNY Stonybrook, The University of Tubingen, and the University of Minnesota in which they grant legitimate species status to Homo floresiensis.  They write:

The scientists applied the powerful methods of 3-D geometric morphometrics to compare the shape of the LB1 cranium (the skull minus the lower jaw) to many fossil humans, as well as a large sample of modern human crania suffering from microcephaly and other pathological conditions. Geometric morphometrics methods use 3D coordinates of cranial surface anatomical landmarks, computer imaging, and statistics to achieve a detailed analysis of shape.

This was the most comprehensive study to date to simultaneously evaluate the two competing hypotheses about the status of Homo floresiensis.

The study found that the LB1 cranium shows greater affinities to the fossil human sample than it does to pathological modern humans. Although some superficial similarities were found between fossil, LB1, and pathological modern human crania, additional features linked LB1exclusively with fossil Homo. The team could therefore refute the hypothesis of pathology.

The link to the PLoS paper is here.This is the conclusion of the paper:

Our analyses corroborate the previously suggested link between LB1 and fossil Homo and support the attribution of this specimen to a distinct taxon, H. floresiensis. Furthermore, the neurocranial shape of H. floresiensis closely resembles that of H. erectus s.l. and particularly specimens of early Eurasian H. erectus, although it is unclear whether this latter affinity is best attributed to a close phylogenetic relationship or to a size-related convergence in shape. These results also counter the hypotheses of pathological conditions as the underlying cause of the LB1 neurocranial phenotype, with the possible exception of posterior deformational plagiocephaly, a condition without significant adverse health effects.

Of course, this doesn't mean that it is not endemic dwarfism, just that it is not built on a modern human base. In this case, it may represent a Homo erectus base. Why it was so marked is still an unanswered question.It is also quite possible that this represents founder effect followed by years of selection for diminutive characteristics.  It definitely represents a peculiar side branch in human evolutionary history but not one that defies explanation. 

Small People, Big Bird

The BBC is reporting on a fossil discovery on the island of Flores, the last known home of Homo floresiensis. The size of the bird: 1.8 meters tall. Emma Brennand writes:

The bones, thought to be belong to a single stork, are between 20,000 to 50,000 years old, having been found in sediments dating to that age.

The giant bird is the latest extreme-sized species to be discovered once living on the island, which was home to dwarf elephants, giant rats and out-sized lizards, as well as humans of small stature.

"I noticed the giant stork bones for the first time in Jakarta, as they stood out from the rest of the smaller bird bones. Finding large birds of prey is common on islands, but I wasn't expecting to find a giant marabou stork," Dr Meijer told the BBC.

She also writes that it might have been able to prey on the hominins, but there is no evidence that it did. What the heck is in the water out there?

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Ilya Somin Has Fun With the Press

The Volokh Conspiracy has a post about the finding by Colin Groves that the species Homo floresiensis is not pathological but truly represents a species of hominid. He is amused that they are perennially referred to in the press as "hobbits," and writes:

This provides additional scientific confirmation for Tolkien’s Lord of the Rings. After all, Tolkien’s hobbits were clearly a distinct species as well, one that did not interbreed with the other hominids of Middle Earth. We already had proof that the prehistoric hobbits “travelled half a world,” which is evidence that at least some of them were on an epic quest to destroy the Ring of Power just as Tolkien described.

Tolkien’s theories are gathering more and more scientific support all the time. I look forward to equally rigorous proof of the existence of elves, dwarves, balrogs, and orcs. As I pointed out in my first post on this subject, we in the blogosphere have already sighted numerous trolls even more ferocious than those described by the great author.

Frodo lives!

As Dr. Bombay would say: HAW!!

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Colin Groves: The Debate About Homo floresiensis Is Over!

In the Journal of Comparative Human Biology, Colin Groves has done analyses that he claims firmly debunks the idea that the Homo floresiensis remains from the island of Flores are cretins. The story, from OneIndia, reports:

Groves compared the Flores bones with those of 10 people who'd had cretinism, focusing on anatomical features that are typical of the disease.

He found no overlap.

Groves' research appears in the journal of [sic] Journal of Comparative Human Biology.

Previously, researchers William Jungers and Karen Baab, both from Stony Brook University Medical Center in New York, studied the skeletal remains of the female (LB1), nicknamed "Little Lady of Flores" or "Flo" to confirm the evolutionary path of the hobbit species.

I suspect that the debate is not over, simply because this set of remains is so odd when compared to the remainder of the human fossil assemblage.

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New Research Pushes Back Occupation of Flores

It is now thought that the inhabitants of the island of Flores, from whence come the hominid euphemistically known as "the hobbit," may have been on the island as early as one million years ago. NewsDaily picks up the Reuters story:

In their paper, the researchers said they found 45 stone tools in Wolo Sege in the Soa basin in Flores.

Led by Adam Brumm at the Center of Archaeological Science in the University of Wollongong in New South Wales, Australia, the researchers used new dating methods and found that the stone tools were about a million years old.

"It is now clear, however, in light of the evidence from Wolo Sege, that hominins were present on Flores (a million years ago). This suggests that the non-selective, mass death of Stegondon sondaari and giant tortoise ... could represent a localized or regional extinction," they wrote in their paper.

A lot of evolution can happen in a million years.

Pictures of the Liang Bua Excavations

The Sacramento Bee has lots of high resolution pictures of the excavations taking place at Liang Bua, the site of the discovery of Homo floresiensis.

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The Shrinking Primate Brain

According to a story from Yahoo news UK and Ireland, research now suggests that some primate brains, which have always been thought to be ever-expanding throughout primate evolutionary history may be shrinking and that this may apply to Homo floresiensis as well. The article notes:

Stephen Montgomery, one of the researchers from Cambridge University, said: "The discovery challenged our understanding of human evolution and created much debate about whether H. floresiensis was a distinct species or a diseased individual.

"Much of the debate about the place of H. floresiensis in the primate tree is centred around its small size, in particular the small brain size. The argument raised has been that the evolution of such a small brain does not fit with what we know about primate brain evolution.

In hindsight, this is not so unusual. Selection acts to mold species into what is best adapted for the environment that they are in. We have seen a shrinking of the modern human brain over that of Neandertals (a drop of about 300 cc) as well as a general shrinking of tooth size and facial size. It simply wasn't needed any longer.

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Homo floresiensis: An Early Split?

Debbie Argue of the Australian National University has published research suggesting that the remains consisting of Homo floresiensis diverged from the main hominin/hominid line as early as the early Pleistocene or late Pliocene, between 2 and 2.5 million years ago. The story, in ANU News, reports:

“Until now much of the debate about H. floresiensis has rested on analysis of the morphology and measurements of the remains found on the Indonesian island of Flores in 2004,” Ms Argue said. “Despite evidence supporting the idea that H. floresiensis constitutes a new species, some researchers continue to argue that it is the remains of a sick modern human or a near-human ancestor affected by island miniaturisation.”

To try to settle the debate, Ms Argue and her colleagues compared up to 60 characteristics from a range of early hominins, including H. erectus, and modern humans. They used two different computer-based modelling systems, testing relationships between the species to find the most parsimonious, or simplest, evolutionary line.

“Our cladistic analyses created two very similar evolutionary trees that establish a very early origin for H. floresiensis back around the emergence of the very first members of the Homo family. This suggests that H. floresiensis was not a sick modern human, not even a very close relative.

This, of course, assumes that the remains are not pathological, a position that has adherents. Recent studies have suggested that this is not the case, however. One has to be very careful in conducting cladistic analyses, which are trait driven, not morphologically driven. The specimen involved cannot have post-mortem deformation and the traits must be extremely clear. The article continues:

“The late survival of H. floresiensis on Flores could turn over the idea that H. sapiens was the only hominin around after the extinction of H. erectus and the Neanderthals,” Ms Argue said. “These two ideas represent paradigm shifts in the field of anthropology, forcing us to reconsider our long-held ideas about our species and its place in the world.”

If there was a second species running around after the transition from Homo erectus to Homo sapiens, it does raise questions about how many there might have been at other times. There is, for example, considerable morphological variation in Homo erectus in China, when compared to that of South East Asia and Africa. Whether this is suggestive of more than one species is not quite clear, though. If human evolutionary history is more like a bush than a tree, then this finding is in keeping with that idea. It is the same thinking that drove the idea to split Homo erectus into Homo erectus and Homo ergaster.


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As Go the Hippos, So Goes Homo floresiensis?

One hippopotami cannot get on a bus, because one hippopotami is two hippopotamus.

(Alan Sherman)

According to news from Madagascar, island endemic dwarfism affects the development and size of the brain. Science Daily has a story on fossil remains of ancient hippopotami.

By examining the skulls of extinct Madagascan hippos, Museum scientists discovered that dwarfed mammals on islands evolved much smaller brains in relation to their body size. So Homo floresiensis may have had a tiny brain because it lived on an island. This is something which has been at the heart of the debate of the Hobbit’s origins, whose remains were uncovered on the Indonesian island of Flores in 2003.

This was put forth as an explanation some years back but this is the first time I have heard it fleshed out. Read the whole thing.