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A Homo floresiensis premolar will be drilled, and DNA extracted, according to a Nature News piece passed on by Razib, John Hawks, and Dienekes. This is not the first attempt at extracting hobbit DNA, the news article explains,

“Five years ago, two teams, one from ACAD and one from the Max Planck Institute of Evolutionary Anthropology in Leipzig, Germany, attempted to recover DNA from another H. floresiensis tooth excavated in 2003. Both attempts failed.

Now, a team led by Christina Adler, a geneticist at ACAD, has found that standard sampling procedures could be responsible for the failure to get DNA from the hobbit and some other ancient specimens.”

I’ve been out of the loop for a couple years and have lost track on the advances made in ancient DNA studies. I do remember there was a big hub-bub regarding contamination from excavators and degradation of DNA. Maybe some of the new techniques overcomes these problems.

The lead, Adler, recently published a paper on the advances, titled, “Survival and recovery of DNA from ancient teeth and bones.” Again, I don’t have time to read it and give you a summary because I am studying for my board exams. It seems like the paper advises extracting DNA from the cementum of teeth which has way more DNA than the normal source of aDNA, dentin… But if you’re curious about ancient DNA sequencing, this should be an interesting read.

Nonetheless, it should be very interesting to see what comes from this attempt. I wish the team the best of luck and eagerly await the results.

Speaking of the Johansons and fossils …

Earlier this year, I’ve blogged about the 2009 Human Evolution Leakey Symposium at Stony Brook that I went to. For more about that blog post, click here.

The symposium, entitled “Hobbit in the Haystack: Homo floresiensis and Human Evolution” can now be streamed live through the Stony Brook website. The website also includes previous Human Evolution Leakey symposia. Click here to watch.

Thanks to Afarensis: Anthropology, Evolution and Science for the heads up!

Originally posted on The Prancing Papio

New analysis by a team led by Australian National University doctoral student Debbie Argue showed that Homo floresiensis, nicknamed hobbits, were early hominin and walked out of Africa to Flores. Their findings supports the argument that Homo floresiensis had a unique wrist anatomy that originated from a lineage that lived long before the common ancestor of Homo sapiens and Neanderthals.

With Mike Moorwood from University of Wollongong and Thomas Sutikna from Indonesian Center for Archaeology, Debbie Argue compared 60 skulls and skeletal features from two individual hobbits to those of hominins, chimpanzees and gorillas using cladistic analysis. The result shows that Homo floresiensis “probably took one of two evolutionary paths from Africa to Flores. One began 1.66 million years ago, the other 1.9 million years ago”.

Read more here: Hobbits Walked Out of Africa

Originally posted on The Prancing Papio.

LB1 (Homo floresiensis)

I watched that NOVA special on Homo floresiensis last night. It was extremely well done. The producers covered a lot of angles, interviewed many key players, presented the information in a clear manner and kept it entertaining. I wish more anthropology related documentaries would use this show as a template.

In lieu of resonating more noise in the echo chamber, I’ll pass you onto John Hawks‘ minute by minute review of the show. But I do want to say the show really effectively addressed some of the critics of the Flores hobbit, including me, by reminding us that evolution is not linear. And even though we’ve seen a linear pattern in previous hominid brain size growth patterns and associated archaeological complexity, it is possible a smaller brained hominid also evolved simultaneously. If I were teaching a paleoanthropology class, I would show this documentary for sure.

For those of you who couldn’t watch it, it is online now in both Quicktime and Windows Media formats. Watch it.

You may have gotten a heads up from John Hawks that a new documentary on Homo floresiensis is around the bend. It is actually going to air tomorrow and you should catch it. It is titled “Alien From Earth,” premiering tomorrow Tuesday, November 11 at 8pm. I’ll definately be watching.

You’ll be seeing clips from Mike Morwood, Dean Falk, Matt Tocheri, Bill Jungers, and David Lordkipanidze explaining several lines of inquiry in regards to whether or not H. floresiensis unusual features are the result of disease, or the result from the “island effect” that often causes large creatures to evolve to be small, or a previously unrecognized branch of the human family tree.

Homo floresiensis foot compared to a modern human's

Dean Falk will be providing an explanation of her 2007 CAT scan of the H. floresiensis brain and the comparisons she did to microcephalic brains. If you don’t remember, she believes the hobbit represents a healthy, and so far unique, specimen of ancient humanity. But as you may also know, the hobbit’s brain size is really small — around 380 cc and the archaeological assemblage attributed to H. floresiensis is way more advanced than what we’ve seen made by other hominids with similar brain sizes.

Matt Tocheri will be providing an explanation of his 2007 analysis of the wrist bones of the hobbit and comparison to African apes. Tocheri argues that based upon wrist bones, Homo floresiensis is for sure a separate species because the bones are indistinguishable from ancestral African apes or other early hominin-like wrists and resemble nothing like modern humans and Neandertals. Bill Jungers will be arguing that he see similarities of the hobbit’s bones to that of Australopithecus afarensis.

Homo floresiensis mandibles

And since the estimated brain to body mass ratio of H. floresiensis lies between that of Homo erectus and the great apes, David Lordkipanidze discusses the possibility that H. floresiensis could be an unsuspected of our evolutionary tree.

All in all this seems like it should be an excellent synopsis on the latest research. I believe I’ve covered most of it before but video is pretty much more entertaining than reading a blog. Anyways, you can see a teaser clip and find more information about the show on the dedicated NOVA web page. And for those that can’t see the show, an online version will appear sometime afterward. Also of related interest is another documentary on H. floresiensis, which Afarensis live-blogged about several days ago. It is titled “The Hobbit Enigma,” and is also viewable online. I’m gonna try and watch that as well. Afarensis clarfied in the comment belowe that “The Hobbit Engima” and “Alien From Earth” are the same documentary — so why not watch it in advance?

According to these press reports, Debbie Argue, of the Australian National University’s School of Archaeology and Anthropology, has produced a new cladistic comparison of Homo floresiensis to many other H. erectus, H. ergaster, H. habilis specimens. I read the releases, and it seems like some gracile australopithecines were also in the comparison set… at least Australopithecus garhi… not too sure though. Her matrix was based off of 40 character states off of the crania and 30 characters off of the mandibles of H. floresiensis and the comparative sample.

She presented her results to her university’s Archaeological Science Conference in February… the news of it is just leaking out now. Her work suggests that the tiny Homo floresiensis are not a biproduct of strong insular dwarfism. A form of speciation also seen on Flores in several species, including a dwarf Stegodon.

Here’s a summary of her results:

• Homo floresiensis is more similar to H. ergaster or H. habilis, indicating that H. floresiensis and H. habilis share a common ancestor.
• H. floresiensis has an arm-leg length ratio that resembles Australopithecus garhi. I don’t know where this is coming from because her character set seemed to be based soley off of skull measurements and not post cranial measurements. Furthermore, LB1, the type specimen for H. floresiensis has a cranial capacity of 417cc. A. garhi had a cranial capacity of 450cc. To Argue, this indicates,

“Flores seems to have evolved around the time of A. garhi, given its primitive arm-leg ratio, whereas H. habilis was moving towards the modern human ratio around the same time…

…[which] means some hominin must have moved out of Africa about two million years ago, which is half a million years earlier than the Dmanisi hominin, which is supposedly the earliest out of Africa.”

This conclusion is in line with conclusion made by academics in September. But the most liberal assesment of when hominins began occupying Flores Island is around 94,000 years ago, there’s a massive gap in the archaeological and fossil record that needs to be acounted for.

More reports have been coming out of last week’s meeting of the American Association of Physical Anthropologists, and one that has caught my attention is a news article summarizing Bill Jungers‘ research on the Homo floresiensis foot morphology. Jungers recently published a research paper reanalyzing Orrorin bipedalism, along with his colleagues.

For this presentation, Jungers looked at the more or less complete left foot of LB1 and says that H. floresiensis had, “flat, clown-like feet.” The photo above are the fossilized H. floresiensis foot bones. In relation to the tibia and fibula fragments, these feet are larger.

From the New Scientist article,

Jungers’ team estimated the length of the hobbit’s feet, which were unusually large for its metre-high frame. “Sort of like a young girl wearing her mum’s shoes,” Junger says…

…And because of their long feet, H. floresiensis probably had to bend its knee further back than modern humans do, resulting in a sort of high-stepped gait. “You would watch these hobbits walk and say they’re walking a little funny,” Jungers says.

The foot had other peculiar features as well. For one, its big toe was quite short compared with the others, similar to earlier hominids such as Australopithecus. However, the shape of the toes, even the short big toe, is like modern human ones, Jungers says. “It has a human morphology and an ape-like proportion,” he says.”

So, he’s associating this morphology with a primitive hominid condition. Not all too novel…. a group did the same last fall, but with the wrist bones.

Nonetheless, I’m not convinced. Why?

A 2006 paper in the open access journal Anthropological Science investigated the big feet morphology of modern humans in Polynesia, which is close to Indonesia. That study found out that Polynesians have much longer and wider feet and hands than the other populations tested. The study gets into a discussion on how micro-evolutionary processes affected this phenotype. It is possible something similar happened to LB1. I’m still uncertain whether or not what we call H. floresiensis are anything but mutant modern humans

For those that wanna read the 2006 paper on big feet phenotype in Polynesia, the citation to that paper is right here:

GONDA, E., KATAYAMA, K. (2006). Big feet in Polynesia: a somatometric study of the Tongans. Anthropological Science, 114(2), 127-131. DOI: 10.1537/ase.00097

PLoS One completely surprised me today by releasing this paper, “Small-Bodied Humans from Palau, Micronesia.” The research comes from South African and American researchers, and the paper was edited by John Hawks, who apparently can really keep a secret it seems. I had no idea about this study and find it a really remarkable find since fossils of another small bodied human, Homo floresiensis, were found about 1,000 miles south of these new findings.

If I read this correctly, a minimum of 25 individuals have been found. Lots more will be found according the authors, which is always welcoming to me. The Palau fossils are of small people, similar in size to the Flores hominins. Preliminary analysis of more than a dozen individuals, including a male weighing about 43 kg and a female weighing about 29 kg, document that these were tiny. Analyzing some of the cranial and dental features like the distinct presence of a maxillary canine fossa, a clearly delimited mandibular mental trigone, moderate bossing of the frontal and parietal squama, a lateral prominence on the temporal mastoid process, reduced temporal juxtamastoid eminences and an en maison cranial vault profile with the greatest interparietal breadth high on the vault indicates that these individuals were simply small H. sapiens adapted for life on a small island.

So how were these bones found? Lead author, Lee Berger, writes to National Geographic News that he was kayaking around rocky islands about 370 miles east of the Philippines, when he found the bones in a pair of caves in 2006. Crazy story! I wish I would find something like that while vacationing. He reports that the,

“the [Ucheliungs and Omedokel] caves were littered with bones that had been dislodged by waves and piled like driftwood. Others had remained buried deep in the sandy floor, and more, including several skulls, were cemented to the cave walls.”

Radiocarbon dating was applied to pinpoint an age for the bones. The antiquity of the bones is between 1,410 and 2,890 years ago, which is remarkably much more recent than 18,000 year old antiquity of the Flores hominins. Along with the small size, the Palau fossils have similar features to H. floresiensis, such as their pronounced supraorbital tori, non-projecting chins, relative megadontia, expansion of the occlusal surface of the premolars, rotation of teeth within the maxilla and mandible, and dental agenesis.

But again, Berger and colleagues do not infer from these features any direct relationship between the peoples of Palau and Flores; however, they conservatively write that these similarities may be a common adaptation in humans of reduced stature. In their own words,

“Based on the evidence from Palau, we hypothesize that reduction in the size of the face and chin, large dental size and other features noted here may in some cases be correlates of extreme body size reduction in H. sapiens. These features when seen in Flores may be best explained as correlates of small body size in an island adaptation, regardless of taxonomic affinity. Under any circumstances the Palauan sample supports at least the possibility that the Flores hominins are simply an island adapted population of H. sapiens, perhaps with some individuals expressing congenital abnormalities.”

Again the paper is published in PLoS One, which is an open access journal. That means you can download the original report and read it for yourself for free. I really recommend you do, this seems like one of the more significant paleoanthropological finds for 2008. Here’s the citation:

Berger, L.R., Churchill, S.E., De Klerk, B., Quinn, R.L., Hawks, J. (2008). Small-Bodied Humans from Palau, Micronesia. PLoS ONE, 3(3), e1780. DOI: 10.1371/journal.pone.0001780

New research from the Proceedings of the Royal Society B raises the possibility that Homo floresiensis was nothing more than population of Homo sapiens that were endemic cretins. The paper, “Are the small human-like fossils found on Flores human endemic cretins?” comes from academics in Australia who

“show that the fossils display many signs of congenital hypothyroidism, including enlarged pituitary fossa, and that distinctive primitive features of LB1 such as the double rooted lower premolar and the primitive wrist morphology are consistent with the hypothesis. We find that the null hypothesis (that LB1 is not a cretin) is rejected by the pituitary fossa size of LB1, and by multivariate analyses of cranial measures. We show that critical environmental factors were potentially present on Flores, how remains of cretins but not of unaffected individuals could be preserved in caves, and that extant oral traditions may provide a record of cretinism.”

What’s cretinism, though? Cretinism is a medical condition that affects growth and development of the organism because the thyroid gland isn’t working correctly. The thyroid gland is a critical endocrine gland, one that secretes a lot of hormones, like thyroxine (T₄) and triiodothyronine (T₃) which do their thing in metabolic reactions and bone growth. Thyroxin and triiodothyronine are essentially made up of iodine, and deficiencies in iodine affect thyroxine and triiodothyronine production — ultimately affecting metabolism, bone development, etc. and resulting in a dwarf-like stature with small brains, but relatively,

“less severe mental retardation and motor disability than neurological endemic cretins.”

The authors of this new study suggest that what is now looked at as Homo floresiensis is nothing more than a group of Homo sapiens who lived on an island that was deficient in iodine. They look at the pituitary fossa, also known as the hypophysial fossa, a depression in the sphenoid bone which cups the pituitary gland, from the virtual endocast Dean Falk and crew made in 2005. The actual osteological feature I was taught is called the sella turcica, or the ‘turkish saddle.’ Anyways, LB1′s sella turcica is long compared to the overall size of LB1.

When compared to other populations, as well as microcephalics, Kabwe, and Mrs. Ples, LB1′s sella turcica length matched that of myxoedematous endemic cretins from China. I’m not endocrinologist, so I maybe completely wrong in this understanding, but I think the reason why endemic cretins have large pituitary glands, and thus larger sella turcicas, is because without a fully functioning thyroid gland, the pituitary has to go in overdrive — it grows larger to pump out more hormones to stimulate the weakly active thyroid. Actually, I’ve found a citation, Yamada et al.’s “Volume of sella turcica in normal subjects and in patients with primary hypothyroidism and hyperthyroidism,” where this pathology is observed and associated just as I suspected.

The authors also compared what others touted as distinctive primitive features of the Flores hominin, such as the double rooted lower premolar, to endemic cretins. But how they did it seems really fishy. They didn’t actually have the LB6 mandible, nor did they have CT scans of the premolars. What they did have was ‘captured images’ from X-ray scans of that 2005 BBC show, “The Mystery of the Human Hobbit.” Yes, you heard me right. They had screen shots from a television show, where the X-rays of the teeth flashed on the screen. Now, I know accessibility to fossils is a big problem in paleoanthropology, people just don’t wanna share… and researchers often have to resort to less accurate sources to get the data they need. But screen captures from a TV show seems flawed to me.

Why?

The authors make no mention that their screen captures came from HDTV, so I’m assuming they plucked it off of standard analog TV resolution. That’s like 704 pixels × 480 pixels resolution, the equivalent of about 0.3 megapixels! A run of the mill digital camera shoots at 7 megapixels nowadays, and the photo quality is still not that great to do a detailed morphological comparison! Regardless, from a resolution of .3 megapixels, the authors were able to compare and contrast fine details like the buccogingival ridge and measure the diameters of the crown.

To be really honest, I don’t know how they were able to get a scale on their measurements…. surprisingly, they didn’t include their image captures. I checked the supplementary materials and don’t see any screen capture of the X-rays included. So I did some sleuthing of my own. The BBC show they got the screen captures from is online, on Google Video. I’ve linked it above. At 5 minutes and 48 seconds, the X-ray of the premolar flashes for a total of seven seconds. I’ve taken a screen capture of the closest zoom of the premolar, and uploaded it. You can get an idea of what sorta resolution we’re talking about. I’m not too convinced one can extract accurate measurements from this, especially without a scale!

The authors go on to compare a whole slew of post cranial features, such as the humeral torsion and the ‘primitive’ wrist bones — stuff we saw in September of 2007, when “The Primitive Wrist of Homo floresiensis and Its Implications for Hominin Evolution,” came out in Science. The authors conclude that the primitive wrist morphology is also a characteristic of myxoedematous endemic cretins, who in total, have brains about half the size of normal humans, way smaller bodies )the don’t grow much taller than 4 feet), and ancestral teeth and wrists. This again is all because iodine wasn’t present in their diets, so important thyroid hormones that aide in growth and development weren’t made readily.

I’d like to believe this paper, really I do. I’ve always had an inkling that Homo floresiensis was a pathological variant of humans When I look at the photos of myxoedematous endemic cretin crania, which the authors supplied in the supplemental materials, I can see similarities to Homo floresiensis. Though I wonder why the authors resorted to virtual endocasts, screen shots, and previously published measurements to do their study? It could be a case that the fossils weren’t made available to them, which then I don’t really hold the authors accountable for why they went about their study in a creative manner… but with Teuku Jacob dead, I don’t think anyone is holding the fossils from Flores hostage, or are they? Anyone care to comment on that?

One last thing, about endemic cretinism… it is seen in population far away from sources of iodine, such as the Swiss and people around the Alps. Lots of other places show it… but iodine deficiency is rarely found in island dwelling populations. That’s because the ocean and sea has a lot of iodine in it, and any food extracted from the sea… like fish, has lots of iodine in it. It is definately possible Flores hominins fished, though no zooarchaeological remains point to that, and thus had little to no iodine deficiency. Just something to think about.

Obendorf, P.J., Oxnard, C.E., Kefford, B.J. (2008). Are the small human-like fossils found on Flores human endemic cretins?. Proceedings of the Royal Society B: Biological Sciences, -1(-1), -1–1. DOI: 10.1098/rspb.2007.1488

The New York Times is running a profile of Ralph Holloway, a paleoanthropologist that specializes in brain evolution, one of my favorite subtopics in anthropology. The piece is written by Michael Balter, and it overviews his current project research with Homo floresiensis.

In a nutshell, Holloway is on the fence about whether or not Homo floresiensis is a new species, he sees evidence of platycephaly, a flattening of the brain rather than microcephaly, the focus that everyone else is honing in on.

William Kimbel of the IHO over at ASU makes quote that makes me feel as if Holloway’s contributions are done,

“He will be remembered as the major advocate for an early reorganization of the brain in human evolution.”

Maybe I’m reading too much into the quote, but Dr. Holloway is still very much active and continuing some great work. He’s decided not to retire and he’s continued his very lively academic rivalry with Dr. Dean Falk, who respects his position that the evolution of the human brain is not all about size but also about what functional areas were modified. But, Dr. Falk and him are still butting heads over the Homo floresiensis and the Taung child endocasts.