Anthropology.net

A week ago, I shared with you news of Bill Jungers’ conclusions on how the morphology of the Homo floresiensis foot affected its locomotion. Science has dedicated a short two page ditty on this topic and you may wanna check it out for a more authoritative take on it.

In other related Homo floresiensis news, John Hawks was contacted by Peter Brown who wanted to share his response to the claims that the LB1 specimen showed signs of recent dental work. I didn’t share this news, which first really emerged in Kate Wong’s Scientific American blog post, because I felt it was as absurd as the analysis done by Obendorf et al. last month.

The news really emerged from Maciej Henneberg proposition that the mandible of LB1 appears to have a filling, possibly a root canal, in its lower left first molar. This was all based off of a photograph and that would indicate it is a modern human. We all know from Obendorf et al.‘s research how flawed it is to analyze a photograph or screen capture.

Peter Brown supplied a relatively high resolution of the LB1 mandible and I can’t see any indication for a filling on the occlusal surface of any of the teeth, let alone the first molar on the left side.

Furthermore, CT scans of the jaw show no modification either. So, its a dead end line of inquiry. Simple as that.

Culotta, E. (2008). PALEOANTHROPOLOGY: When Hobbits (Slowly) Walked the Earth. Science, 320(5875), 433-435. DOI: 10.1126/science.320.5875.433

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

Another PNAS study to share with y’all, this time I caught the announcement via ScienceNOW. ScienceNOW says the paper is out today, but I can’t find it. Go figure. So all I got to run with is this news report.

The authors of this paper are Adam Gordon, Lisa Nevell, and Bernard Wood. They compared the size and shape of other hominid skulls with that of Homo floresiensis. They conclude that LB1,

“from the island of Flores is unlikely to be a shrunken or diseased Homo sapiens, as some have argued, and that its ancestry may instead trace back to ancient Homo species in Africa.”

Two weeks ago we read a very flawed article that concluded Homo floresiensis was nothing more than a bunch of endocrine-ly challenged modern humans. There’s been a so much back and forthing on whether or not Homo floresiensis is a unique species that is has become tiresome to even keep up with the arguments. Sometimes it feels like ego is at more at stake here than really figuring out human evolution.

This new study seems to want to simplify things. From the news article,

“The researchers gathered published data on six measurements of skull shape, such as the height of the cranium and the forward jut of the jaw, on 2524 modern humans, 30 ancient hominids of various species, and the hobbit. Statistical analysis showed that the hobbit skull most resembled H. erectus skulls from Africa and Dmanisi, Georgia, dating as far back as 1.7 million years ago. Then, because the skull’s tiny size presumably influences its shape in certain ways, the researchers did a second analysis considering the effects of scale–in effect asking what type of hominid, if shrunk to hobbit size, would best match LB1. In this part of the study, LB1 most resembled African H. habilis, the most primitive and small-brained species of our genus, also dated to about 1.7 million years ago.

“This is particularly exciting because … it suggests that we really do have a hominin lineage that split off from our own as much as 1.7 million years ago, yet persisted up until the time when modern humans started peopling the Americas,” says Gordon.”

To recap on some osteological goodness, the six measurements are as follows:

1. Glabella to Opisthocranion, a measurement of the maximum length of the skull. That’s from the front to the back of the skull.
2. Basion to Bregma, a measurement of the of the maximum height of the skull. That’s from the base to the very tip top point of the skull.
3. Euryon to Euryon, a measurement of the maximum breadth of the skull. That’s from one side to the other side.
4. Nasion to Basion, a measurement of the length of the base of the skull.
5. Basion to Prosthion, a measurement of the distance between the base of the skull to the tip of the maxilla (upper jaw).
6. Biasterionic breadth, a measurement I haven’t heard of but looks like it is the width of the base of the skull.

I’m gathering that the authors took these multiple measurements and did a phylogenetic analysis. I am getting this from what was indicated in the above excerpt, they compared a lot of modern humans, fewer hominids of various species, and the hobbit. I don’t have the article to confirm this methodology, but I can only assume that is what they did to figure out LB1 is similar to Africa and Dmanisi Homo erectus, even H. habilis in some regards, based off of the measurements.

But, if you have read this paper, “Remains of Homo erectus from Bouri, Middle Awash, Ethiopia,” you should know how reconstructing phylogeny with cladistic analysis between early Homo species is hard and rather inconclusive. We know general trends and large scale similarities and differences, but when it gets to nitty gritty things, the paltry calvarial evidence for big differences between the African and Asian fossils make it really difficult to say Asian Homo erectus was that much different from African Homo erectus. Instead, it is much safer to say that Homo erectus existence spanned large time frames. And that even with a 1.2 million year old difference in time, Homo erectus from Africa to Asia was pretty much the same thing.

For that reason, I wonder how LB1 can be like Homo erectus… especially a really old African erectus as indicated in the report? Above, I put a lateral view of LB1 as well as a lateral view of a Dmanisi Homo erectus (D2700), one that the authors say LB1 resembles. Just by eyeballing the differences between the two skulls we can see that D2700 is much longer, and has a big difference in the basion to prosthion length.

If we take into consideration the works of Asfaw et al., there aren’t many differences between African and Asian Homo erectus that can be figured out thru cladistics. And Asian Homo erectus persists in the record into much more recent times. So, why isn’t LB1 related to an Asian Homo erectus? They should be synonymous, no? What is particularly African erectus about LB1?

Furthermore, how can a tiny hominid like LB1, with a brain half the size of Homo erectus and an antiquity of only 18,000 years old, be compared to one of the root species of Homo? Some of the earliest Homo had brain sizes of 900 or so cc. LB1 had a brain size of 440 cc. Big difference here folk. The news article reports that they ‘shrunk’ the proportions of other early Homo skulls down to LB1′s size to compare. Is that even a valid way to compare? The very fact that LB1 is distinct is its size, so scaling down comparative measurements seems flawed because we’re comparing apples to oranges watermelons here. You can’t just scale down a watermelon down to the size of an apple and begin to start concluding their similar.

I’m not alone scratching my head over this. Christoph Zollikofer, also has some problems with this cladistic approach. He says the six measurements aren’t enough to

“capture the complexities of skull shape, a concern shared by others. In his view, this kind of analysis might cluster together skulls that are actually distinct. Depending on the species included, says Zollikofer, the approach could end up finding similarities between LB1 and chimpanzees.”

I guess we all gotta wait until PNAS puts out this paper.

Asfaw, B., Gilbert, W.H., Beyene, Y., Hart, W.K., Renne, P.R., WoldeGabriel, G., Vrba, E.S., White, T.D. (2002). Remains of Homo erectus from Bouri, Middle Awash, Ethiopia. Nature, 416(6878), 317-320. DOI: 10.1038/416317a

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

That new paper on PCNT’s role in microcephaly I just covered this afternoon has really sparked my interests. I have done a bit more digging around and came across another very recent paper, published about two weeks ago in Nature Genetics on PCNT’s role in inducing Seckel syndrome when it is nonfunctional. From OMIM, Seckel syndrome is a rare autosomal recessive disorder and it is characterized by growth retardation and microcephaly among other traits.

The paper, “Mutations in pericentrin cause Seckel syndrome with defective ATR-dependent DNA damage signaling” comes by way of researchers in the UK, Netherlands, and Saudi Arabia. From the abstract, you can get a feel for how important PCNT is,

“We now report that mutations in the gene encoding pericentrin (PCNT)—resulting in the loss of pericentrin from the centrosome, where it has key functions anchoring both structural and regulatory proteins—also cause Seckel syndrome. Furthermore, we find that cells of individuals with Seckel syndrome due to mutations in PCNT (PCNT-Seckel) have defects in ATR-dependent checkpoint signaling, providing the first evidence linking a structural centrosomal protein with DNA damage signaling. These findings also suggest that other known microcephaly genes implicated in either DNA repair responses or centrosomal function may act in common developmental pathways determining human brain and body size.”

Andrew Jackson of the Human Genetics Unit of the Medical Research Council, in Edinburgh is lead author. His team’s work along with Rauch’s research really help us see that any alteration in the mechanisms that drive the centrosome, such as in pericentrin, results in microcephaly. I summarized what PCNT encodes for, pericentrin, a protein that makes up the centrosome complex, in today’s previous post. The centrosome is a organelle that functions in regulating the cell cycle and cell division. What the centrosome really does is that it serves as an anchoring point to where microtublues are concentrated. The microtubules serve as ropes and poles which pull and push chromatids are aligned and then separated to help form two daughter cells. Should a component of the centrosome be flawed, say a messed up pericentrin protein because PCNT had mutations, then ultimately cell divsion, growth and development will be affected. Basically, the checkpoint wasn’t passed and mitosis won’t complete properly.

In the case of what we see in Homo floresiensis, we should always consider the possibility that such features are because of mutations in the development of the individuals. Many people were arguing this, they were saying Homo floresiensis‘ features were pathological. I think we’re just beginning to see how this could be, unraveling the functions of key developmental regulating genes.

Again with more confusing back and forthing…. but this time we leave the Neandertals and focus in on debate over whether or not Homo floresiensis is a novel species. New research published in Science, focuses in on the discovery of a mutation in a gene that causes a rare growth condition called MOPD II. People who are diagnosed with MOPD II have small brains and body size but near-normal intelligence which is what we see evident in the skeletal remains of Homo floresiensis and the associated archaeological artifacts. The MOPD stands for microcephalic (or Majewski) osteodysplastic primordial dwarfism, and the Roman numeral two just stands for the type.

Anita Rauch is first author of this new paper, “Mutations in the Pericentrin (PCNT) Gene Cause Primordial Dwarfism.” As you can tell from the title, PCNT is the culprit here. I did a bit of sleuthing to figure out what PCNT does. I figured out it encodes a conserved centrosome protein. Centrosomes play an essential role in microtubule organization and pull chromosomes apart during cell division. Additionally, PCNT forms a large complex with gamma tubulin and other proteins involved in microtubule nucleation. Ultimately, any mutation in this gene would affect the function of this protein in cellular division and development of the organism.

The research was inspired by two unrelated tiny girls living in northern Bavaria as well as Paddy Ryan, a man living with MOPD II. If Rauch and crew’s conclusion holds up, there’s about 100 known people living today with phenotypes seen Flores like hobbits. These are people who have grown up and live with the mutations in PCNT and display the MOPD type II condition which that leads to them being normally proportioned but half-sized. I once saw a documentary on people with MOPD and had thoughts they were similar to what we call, Homo floresiensis.

Another really important part of this study is that it totally challenges the primitive wrist hypothesis paper that came out last September. I critiqued that paper, where the authors argued that carpal bones of the hobbit hominid display ape-like traits. I had beef in that they said the fusion of centrale in the Homo floresiensis wrist was a primitive trait, even though modern humans sometimes display this feature. Rauch addressed this as well as the other primitive traits seen in the hobbit wrists. She writes that mutations in PCNT make for bony anomalies of the hand and wrist. I’d love to read what the primitive wrist folk have to say about this.

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.

I’ve done so much flip flopping on whether or not Homo floresiensis is in fact a new species of human over the last 3 years that I sometimes forget what opinion I currently hold. The only consistency in my debate has been the call for analysis of the other remains. It seems like I got my wish after catching last week’s Science publication of the The Primitive Wrist of Homo floresiensis and Its Implications for Hominin Evolution. The title is pretty self-explanatory.

H. floresiensis is a hominin found in 2003 from the Ling Bau cave on the island of Flores in Indonesia. The bones found are about 18,000 years old. There’s been a lot of back and forth discussion whether or not H. floresiensis deserves a new species. At first people thought it was a representative of H. erectus, then it was suggested that H. floresiensis is a primitive microcephalic modern human. I like many others held this opinion.

Earlier this year, Dean Falk did a comparison of the endocranial volume of the H. floresiensis skull, LB1, to a number of microcephalic humans, and primates. She found H. floresiensis to be uniquely different in size and morphology. For many that wasn’t enough because, we don’t have many microcephalic human skulls to measure and compare too.

The other bones found at the site are just as diagnostic, especially the bones of the wrist and hand. So what Tocheri et al. did was to use fancy 3-D methods to calculate all the different dimensions, areas, and angles of the trapezoid, scaphoid, and capitate bones and multivariate statistics were used to compare the Flores carpal bones to set of archaic and modern humans, Neandertals, australopithecines, gorillas, chimpanzees, and also OH 7 a.k.a. Olduvai Hominid № 7 or the type specimen for H. habilis. Here’s a quick run down on what they found.

The trapezoid is the main bone where the index finger’s metacarpal articulates with the rest of the wrist. It’s a small bone in modern humans. The Flores trapezoid is wedge shaped like humans but has a different orientation on the ulnar side. Here’s the figure they showed which illustrates LB1, Flores trapezoids, compared to the others.

The Flores scaphoid shape and articular surfaces are more triangular in shape and lacks the larger articular surface on the palmar side which is seen in modern humans and Neandertals. Curiously, the scaphoid also has a fused centrale; a condition seen in H. habilis.

The authors say this fusion is a primitive condition for all hominins, because in modern humans it is separate. But that is not entirely true. The centrale sometimes fuses onto the scaphoid as the tubercle of the scaphoid; but occasionally it stays separate. It is not as definitive as they authors are making it out to be.

Anyways, here’s the line up of the scaphoid comparison.

Last but not least, is the sweet capitate. The capitate is the largest bone in the wrist and it falls smack dab in the center. Aside from the size, I remember the capitate because it has a rounded head which reminds me of Captain Picard’s bald head. And no, I’m not a Star Trek fan… it just that this bone has a remarkable resemblance to his unforgettable head.

Parts of the capitate, like the head, look like a chimpanzee’s capitate. Check out the light blue part below. But others, such as the proximal surface (green part) resemble modern humans. All in all the authors say the articular facets and shapes are more primitive than not because of a “waisted neck” characteristic that I don’t know about.

Can you see it?

I must admit they have a pretty complete line up of capitates, and the images let us all see for ourselves how these three bones compare…

…But I wonder why they didn’t include microcephalic or even dwarf humans into the mix?

That’s my biggest complaint with this study. You’d think that they’d include them, considering the biggest competing hypothesis is the whether or not H. floresiensis was a bunch of small humans. I’ve never seen bones from a microcephalic’s or dwarf’s hand to say that their bones would be more primitive than not… but I would assume since dwarf skeletons are much more distorted they would have different morphological features.