Anthropology.net

The Journal of Experimental Biology has published an interesting paper about some unique features in sprinters: longer toes and shorter ankle joints. The only one flaw is that their sample size is limited, they only compared 12 collegiate sprinters with 12 non-athletes of the same height. Regardless, from a physical anthropological point of view, this comparative & biophysical analysis informs us what traits help humans sprint faster.

The significance of long toes and short ankle joints can be explained from a purely physics perspective. From the start of a sprint, the only way a human can accelerate is through the transfer of energy from the force of the leg muscle to pushing on the ground. The advantage of longer toes provide maximum contact with the ground just a little bit longer than shorter toes.

The ankle joint is shorter because there is an inverse relationship between tension force and distance — think torque and angular momentum. Sprinters have a 25% shorter distance between the Achilles tendon and center of rotation of the ankle. The Achilles tendon is the common attachment of the gastrocnemius and soleus muscles into the calcaneus. When contracted, these two muscles flex the knee and plantar flex the foot. With a shorter ankle joint, these muscles shorten less for the same joint rotation. If muscles shorten less, then they shorten more slowly. This facilitates them to produce greater force that more than compensates for the reduced leverage.

When these two adaptations are combined, the authors figured that the greatest acceleration is achieved when the Achilles tendon lever arm is the shortest and the toes are longest. Comparing these anatomical features to other sprinting animals, like ostriches, greyhounds and cheetahs, they authors observed that they also have feet built for sprinting with similar features.

The authors, who are not physical anthropologists, state in press releases that they think these adaptations could have had some evolutionary backing. They raised the tired hypothetical scenario where early human ancestors, now those with longer toes and shorter ankle joints, were better able to run away from the saber tooth tiger or marauding tribe and reproduce that trait. But I disagree, while there certainly is an inherited component to the size and shape of our bones, muscles, and joints, our bodies are malleable and depending on training, our bones and muscles can change!

Furthermore, the majority of humans are not sprinters, as I understand it. In fact, most of us are good at long distance motility. Our bodies are extremely inefficient at sprinting but we’re really good at staying the course! Most of us have lots of Type I muscle fibers, slow but fatigue resistant fibers. Anyways, I don’t mean to rag them on this concept, as I mentioned they aren’t physical anthropologists and they seem to only be speculating on this last point. Either way, I believe the observation they made is interesting!

Knight, K. (2009). SHORT HEELS GIVE ELITE SPRINTERS THE EDGE Journal of Experimental Biology, 212 (22) DOI: 10.1242/jeb.039735

Lee, S., & Piazza, S. (2009). Built for speed: musculoskeletal structure and sprinting ability Journal of Experimental Biology, 212 (22), 3700-3707 DOI: 10.1242/jeb.031096

That is what University of Liverpool’s Emma Nelson probably would have said if she were to meet our hominan ancestors in person. Known to hold true in anthropoids (humans, apes and monkeys), the index (second digit) to ring (fourth digit) fingers ratio or 2D:4D is an indication of how much an individual were exposed to androgen (such as testosterone) in the womb. The more androgen you are exposed to, the longer the ring fingers are (and the shorter the index fingers are compared to the index fingers).

Nelson et al. believe that a high ratio (longer index finger, shorter ring finger) suggests monogamy (or pair-bonded) while a low ratio (shorter index finger, longer ring finger) suggests polygamy (or non pair-bonded). Simply put, individuals with high androgen level is likely to be non pair-bonded and the telltale sign is in the index and ring fingers. Also, some controversial studies had suggested that both men and women who receive high levels of androgen in the womb are more likely to be stronger, faster, and more sexually competitive.

Nelson and her researchers recently looked at the fossils of two Neandertals and one Australopithecus afarensis with complete index and ring fingers to determine their 2D:4D. They found that Neandertals had long ring fingers, suggesting that they were polygamous just like modern day primates that live in groups. A. afarensis on the other hand, had long index fingers. Nelson is puzzled by this discovery. “These were small creatures that probably lived in groups and were being eaten by predators. How do you keep from mating with different members of the group?”, she said.

Indeed it does not make sense for A. afarensis to be monogamous if they live in groups. Notice that Nelson et al. only used one A. afarensis fossil to get the 2D:4D. Perhaps it is not their fault that only one A. afarensis specimen had complete index and ring fingers but such are the dilemma of using fossil specimens to generalize a whole species.The result might just be a statistical outlier. However, I can’t speculate the result or the implications but anyone that are familiar with statistical data knows that a small sample size leads to a higher sampling error. Also what would a 2D:4D = 1 (same index and ring finger length) be?

Interesting enough, John Hawks at John Hawk’s Weblog mentioned the correlation of 2D:4D with male homosexuality (Robinson and Manning, 2000). I would know about this. In fact, my 2D:4D is indeed low.  Robinson and Manning predicted right! Maybe …

I do find both Nelson et al. and Robinson and Manning (2000) research interesting but I would like to stress that the results are mere predictors and correlations. Take it with a grain of salt. Don’t go measuring 2D:4D of your future spouse, boyfriend or girlfriend and accuse them of not being monogamous or a homosexual.

Emma Nelson and her team presented their research at this year’s Society for Vertebrate Paleontology meeting held in Bristol, United Kingdom. Read more about Emma Nelson’s research.

References:

Reilly M. 2009. Human Ancestors Conflicted on Monogamy. Discovery News. Retrieved September 25, 2009, from http://dsc.discovery.com/news/2009/09/24/human-monogamy.html

Robinson SJ. Manning JT. 2000. The ratio of 2nd to 4th digit length and male homosexuality. Evolution and Human Behavior 21(5): 333-345. [doi:10.1016/S1090-5138(00)00052-0]

Originally posted on The Prancing Papio

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.

Bergmann’s rule is an observation that body mass of endotherms increases with altitude and colder climate. Neandertals fit this rule, their barrel chests and wide hips, indicate they had large bodies, and thus smaller surface area relative to their body mass. This feature made them comparatively inefficient at radiating their body heat off into the surrounding environment than smaller bodied hominins…. which is an advantageous trait to have in cold environments.

Another similar theorem, Allen’s rule, summarizes the observation that endotherms from colder climates usually have shorter limbs compared to counterparts from warmer climates. Similar to Bergmann’s rule, shorter limbs keep blood and heat closer to the core of the body, reducing heat loss.

All this may sound like adaptionist mumbo-jumbo, but researchers have observed these adaptations to cold climate in other animals. Compare the profiles of polar bears, walruses, and mammoths to cheetahs, antelopes, and giraffes, and you’ll see how some of this makes sense.

Homo neanderthalensis from la Chapelle aux saints

Anyways, I digress. There are two different camps currently hashing out whether the Neandertal facial morphology is due to random genetic drift or a mix of archaic traits and climate influenced adaptations. One of the more hotly debated facial traits, the Neandertal nose, doesn’t quite fit what we expect to see in cold climate adapted species. The Neandertal nose is broad and wide, a feature seen in tropical climates. Physiologists have shown that narrow noses better warm the air being inhaled and prevent evaporation of water in such dry environments by recapturing moisture during exhalation. Wide noses dissipate heat very efficiently.

Some researchers, like Milford Wolpoff, have suggested that there’s a growth and development reason to why we don’t see narrow Neandertal noses. For example, the effects of large teeth and broad palates could have affected the reduction of the nasal aperture, and were most likely inherited traits from Pleistocene ancestors. In a new Journal of Human Evolution paper that Dienekes pointed out this week, researchers from the University of Iowa have investigated the relationships between nasal breadth, intercanine breadth, and facial prognathism. The paper is titled, “The paradox of a wide nasal aperture in cold-adapted Neandertals: a causal assessment.” They tested variants of the following hypothesis: Does the distance between the two upper canines correlated with nasal breadth in modern and archaic Homo?

Intercanine Breadth Measurement

Their sample set of modern humans included 119 crania of Bantu people and 112 crania of Western Europeans. The sample of human ancestors included 11 from the early Upper Paleolithic, 9 from the late Upper Paleolithic all coming from Eurasia. They also included 15 samples from the late Stone Age in Africa, and 14 Pleistocene Homo. Like I mentioned earlier, they measured the distance between the two canines, known as the ICB. In anatomical terms that’s the distance between the lingual tubercles of the maxillary canines, or the pointy parts of your vampire teeth. The lower facial prognathism (BPL) is a measurement of basion to prosthion. Upper facial prognathism (BNL) is a measurement of basion to nasion. Of course some fossils didn’t have all the measurements so predictions were made by least squares regression.

The authors conclude that intercanine breadth cannot fully explain nasal breadth from their sample set, which goes against what anatomist Gustav Schwalbe said in the later 1800′s and what E.V. Glanville reconfirmed in the late ’60s. They also note that the development of the anterior palatine bone does not affect the growth trajectory of the breadth of the nose. While, they do suggest that nasal breadth is affected by the ICB, the lower facial prognathism impacts nasal breadth more than any other trait.

They finally suggest that the plesiomorphic retention of a prognathic lower face is due to the extended time the premaxillary sutures remain open during development. This is lower face prognathism is not a derived trait, but rather a retention of archaic traits, seen in early humans. But that’s not to say the Neadertal nose never adapted to cold climates while the rest of their body did. Neandertals from colder climate have been characterized with a more narrow superior nasal dimensions, which have ultimately been linked to aspects of airflow dynamics.

N HOLTON, R FRANCISCUS (2008). The paradox of a wide nasal aperture in cold-adapted Neandertals: a causal assessment Journal of Human Evolution DOI: 10.1016/j.jhevol.2008.07.001

What you may call the hip or pelvis is actually formed by the joining of ilia, ischia, pubis bones to the sacrum and the coccyx. The shape of the human pelvis is unique amongst primates and part of the complex of anatomical changes which allow us for bipedal motility.

The Male Pelvic Girdle

Between males and females, the pelvis is significantly different. I’ll review some of the features that should be common knowledge to anyone with a forensic or physical anthropology background. For starters, where the two pubis bones meet, at the lower edges of the two inferior public rami, there is a feature called the subpubic angle. Males have an angle smaller than 90 degrees, while females have a larger one. You need not take a protractor to make this observation. If you got a pelvic girdle with subpubic angle wider than a right angle then you most likely have a female… anything smaller and you have a dude.

But there is more, under the posterior inferior spine of the illium, and above the ischial spine, exists a feature called the greater sciatic notch, a sort of passage way for the piriformis muscle and the sciatic and posterior femoral cutaneous nerves. In females the notch is broader than males. Another feature, the biiliac width, a metric measurement made from the widest point between the two ilia is also a sex determining feature. Relative to their overall body sizes, females have large biiliac widths. The two ilia seem to flare out wider in a female. With a wider biiliac width, comes a wider pelvic inlet or the circumference of the lesser pelvis forms.

The Female Pelvic Girdle

So why do females have larger pelvic inlet, width between the two ilia, and a larger subpubic angle? That’s because they give birth. A wider pelvis allows for better distribution of the added weight that comes during pregnancy. A wide pelvic inlet allows for more space to hold the baby in utero. Furthermore, passing the largest brain to body size mammal through a narrow pelvis would not only be painful, but poses a serious danger to both the mother and baby during childbirth.

The average female adult has a biiliac width of 28 cm. Certain populations, such as Greek women have biiliac widths of 27.5 +/- 2.29 cm, falling within the average (Steyn et al., 2008). Inupiat women have widths averaging 28.6 +/-  0.2 cm, Finns at 27.9 +/- 0.2 cm (Ruff et al., 2004). But, east Asian populations, such as the Japanese have smaller pelvises, with less variation. The average billiac width of women from Japan is around 27.2 +/- .02 cm (Ikoma et al., 1988).

This all makes sense, east Asian people are on average smaller than white people or people from Africa. In fact, anthropologists have regularly relied on estimating body size and mass from biiliac measurements. The average Japanese woman is 153 cm tall, while European women from Germany or the Netherlands average 166 cm in height. You can see such a distinction when comparing Finnish and Japanese pelvic girdles. Asian newborns babies are also have smaller weight at birth (3.2 kg) compared to white babies (3.4kg). A  white woman with a wider pelvis can give birth to larger white babies.

So what happens when a white man, with big white genes, reproduces with a small Asian woman? Well, Razib pointed out a new study in the American Journal of Obstetrics and Gynecology which reviews the impact of such couplings. The paper, “Perinatal outcomes among Asian–white interracial couples,” documented that 33% of such couples surveyed had caesarean deliveries. The latest NIH data on the caesarean rate in the United States is 30%.

The authors suggest that the reason why such couples have 3% more C-section deliveries is that the smaller Asian pelvis is less able to accommodate babies of a certain size. The Asian-white couples had larger babies, with a median 3.36 kg for Asian-mother/white-father versus 3.21 kg for babies from Asian-Asian couples.

There’s a much larger discussion to be had than just reviewing a review of the anatomy and evolutionary history of such a study. Ever so recently, we hosted yet another post on the anthropology of race, which summarized that, “race does not exist in the world in any ontologically objective way.” If you’ve been a regular reader, you would know I’ve tackled this mantra many times. What could be anymore ontologically objective than such a study?

The nature of an Asian is on average smaller in body size than other humans. Of course there is variation. There are some large Asians, but the are very few. The majority are smaller in comparison to other humans. Studies like this show that Asian-mother and white-fathers produce larger babies and have increased rates of C-sectiond deliveries.

There are serious health issues with C-section deliveries, and thus serious, tangible biologically race related issues when people from two different populations mate and increase their chance of having a C-section delivery. The health issues I mention are the increased childbirth mortality rate. On average 1 in every 10,000 women who gives a natural birth will die during childbirth, while 1 in every 2,500 women who undergo C-sections will die during childbirth. In otherwords, women who give birth via C-section are 4x as likely to die. Furthermore, caesarean deliveries increase the risks for malpresentation, placenta previa, antepartum hemorrhage, placenta accreta, prolonged labor, uterine rupture, preterm birth, low birth weight, and stillbirth in their second delivery. The paper also outlines the higher prevalence of gestational diabetes for such interracial couplings.

That all being said, race is not just a social construct. How we interpret biological differences, such as pelvis size, skin color, etc. are not socially constructed but real observations, made from quantiative analysis. There are distinct anatomical, genetic, even behavioral differences that are not derived soley from stereotypes.

Michael J. Nystrom, Aaron B. Caughey, Deirdre J. Lyell, Maurice L. Druzin,Yasser Y. El-Sayed (2008). Perinatal outcomes among Asian–white interracial couples in American Journal of Obstetrics & Gynecology 199 (4), (385.e1-385.e5) DOI: 10.1016/j.ajog.2008.06.065

Michelle Glantz, Sheela Athreya, and Terrence Ritzman have taken up yet another a reassessment of Teshik-Tash Neandertal child in the latest issue of the American Journal of Physical Anthropology. They’ve published the paper under the title, “Is Central Asia the Eastern Outpost of the Neandertal Range? A Reassessment of the Teshik-Tash Child.”

The child, Teshik-Tash 1, was found in 1938 in Uzbekistan. There’s been a lot of back and forth since the original publication on whether or not Teshik-Tash is really a Neandertal. I won’t be reviewing all the literature since the authors do a good job covering the discussion. The authors argue that one of the main reasons why Teshik-Tash is still considered a Neandertal is because of historical precedence. They also argue that this precedence has prevented people from fully appreciating variation.

They’ve found several things in the literature that may have affected its assessment, such as a reconstruction of the cranium. They claim that distortions and missing elements may have affected the morphology of the sample. For example, missing pieces of the fossil at the base of the cranium are parts that would affect the shape and size of the foramen magnum — a trait that has been used to attribute the Teshik-Tash child as a Neandertal. I’ve taken the liberty of highling an image, provided by the authors, to better illustrate the missing pieces.

Missing Parts of the Teshik-Tash Neandertal

But because of the not measuring reconstructions, there’s a lot of missing data. To compensate, expectation-maximization algorithms, a type of maximum likelihood estimations were deployed as well as  multiple imputation, a technique for fitting models to incomplete data sets. Ultimately the data was analyzed under a principle component analysis and multinomial logistic regression. These statistical procedures are more fitting for small sample sizes with missing data.

The results suggest that Teshik-Tash share a lot of cranial and mandibular similarities to Upper Paleolithic modern humans, and fail to support the suggestion that Teshik-Tash is like its European Neandertal sub-adult comrades. But there really aren’t any other Central Asian Neandertal subadults to say for sure that this guy ain’t Neandertal. Until more specimens are found from that region, its really hard to say that the morphology swings either way.

Glantz et al. give about one sentence to the results of Krause et al.’s mtDNA analysis of Teshik-Tash from last year. A shame they play down the results. The results, which I covered, conclude that 190 base pairs from the Teshik Tash kid’s mtDNA is very similar to other Neandertals. The seqeunce can be found under this Genbank entry. I’ve decided to do a quick phylogenetic comparison of these 190bp to modern humans and other Neandertals. Here are the results, which clearly show Teshik-Tash, in these 190bp, is definitely Neandertal (the Teshik-Tash individual is the yellow, unknown item in the tree, and click thru to see a larger image):

Comparison of Teshik-Tash mtDNA to Other Humans & Neandertals

I’m not saying the DNA analysis is definitive. If more DNA could be sequenced from the mitochondrion of Teshik-Tash, that would be better. But given that ancient DNA is fickle, what we have is pretty damn convincing. Despite the argument for distortion, previous morphological analysis (studies that didn’t rely on compensating for missing data) also support the claim that Teshik-Tash is a Neandertal. With these two lines of evidence, why then are we beating this dying horse?

Glantz, M., Athreya, S., Ritzman, T. (2008). Is Central Asia the eastern outpost of the Neandertal range? A reassessment of the Teshik-Tash child. American Journal of Physical Anthropology DOI: 10.1002/ajpa.20897

Pinpointing when language became a prevalent trait during human evolution has been tricky. Last fall we read a paper which documented that Neandertals have the same FOXP2 sequence as modern humans. FOXP2 is a transcription factor associated with language. Two recent papers have shown that chimpanzees and humans have very similar structures in the brain that function in processing and producing sound. And despite the fact that several non-human apes have well known, documented histories of comprehending and communicating in sign language or with language boards, there has not been a consensus on when language definitively arose.

Rolf Quam, of the American Natural History Museum, along with several other colleagues have been investigating this issue. He’s been looking at the ear bones of Homo heidelbergensis, and he thinks they were capable of hearing sounds similar to how people do today. In other words, their ear bone anatomy is remarkably similar to modern Homo sapiens, despite the fact that Homo heidelbergensis is not directly related. The team reported their findings July 3 in Paris during the Acoustics ’08 conference.

From the press release,

“The skulls are from a site in Atapuerca, Spain called Sima de los Huesos, or “pit of the bones.” The Atapuerca research team, which includes members from many disciplines and universities, used CT scanning of the skulls to reconstruct the size and shape of the ear canals, Quam says.

The length of the ear canal determines what frequencies of sound waves resonate, and are therefore heard more easily, says Sunil Puria of Stanford University, who models hearing patterns from ear structure.The geometry of the ear canal reveals that the hearing patterns of H. heidelbergensis overlapped with those of modern-day humans. Both modern people and the ancient hominids have especially sharp hearing in the 2 kilohertz to 4 kilohertz frequency range, where much of the sound energy of spoken language is transmitted….

…The results don’t necessarily show that the ancient humans could speak, Quam says. “We’re saying that the ear changed for some reason and that those changes facilitated the possibility of language development,” he says.”

Like in modern humans (shown in solid blue), the ear canal of H. heidelbergensis (shown in red and magenta lines) had a peak in auditory sensitivity in the frequency range from 2 kilohertz to 4 kilohertz, where much spoken information is transmitted. Chimpanzees (shown in solid green) have a dip in sensitivity in that range.

All this really shows is that H. heidelbergensis could hear in the frequency range as modern humans. While I think it is very possible H. heidelbergensisis communicated, this research can not indicate that they used their ‘modern ear anatomy’ for anything special.

Erik Trinkhaus published a study, along with Hong Shang, in the July issue of the Journal of Archaeological Science on what they consider the earliest evidence of footwear of modern humans. The paper is titled, “Anatomical evidence for the antiquity of human footwear: Tianyuan and Sunghir.” They compared and contrasted the morphology of a couple foot bones of humans to human ancestors to see if they can find the effects of shoe wearing on foot bone anatomy.

Before we get into this, I want you to be aware of a couple things. First, the earliest direct evidence of footwear, and by direct I mean actual artifacts of shoes, that I know of are mostly complete sandals from California that date to 9,000 years ago. Other evidence comes from fossilized footprints. Looking at the effects of footwear on foot bones is indirect.

Second, this is not Trinkhaus’ first attempt at establishing the earliest record of footwear. In 2005, he published, “Anatomical evidence for the antiquity of human footwear use,” in the same journal as this current paper. In that paper he sampled foot bones from humans as old as 100,000 years to 10,000 years. He specifically looked for changes in human foot anatomy.

This earlier paper relied on an assumption that shoe wearing causes phalanges or toe bones to become more delicate, or gracile. In other words, the four smaller toes on each foot of people that walk barefoot, flex to allow better traction. This torsional flexion promotes robusticity and sturdy phalanges. In contrast contrast, supportive footwear, like sandals and tennis shoes, lessen the load and force on the four small toes, thus ‘weakening’ them. I’ve seen it myself, in people from the Caribbean and Africa. Often times these people do not wear shoes, or they wear poor shoes. Their feet are much wider than mine and other shoe wearing people, so are their toes.

In the 2005 paper, Trinkaus looked at the toes of western Eurasian human skeletons from the Middle and Upper Paleolithic. He saw that the anatomy of the foot began to change around as early as 30,000 years ago, becoming more gracile than robust Neandertals and early Homo sapiens.

As you can tell from the title of the current study, the two subjects are Tianyuan and Sungir. The specimen from Tianyuan, Tianyuan 1, was actually published by Hong Shang as well as other authors (link is dead, I know). The Tianyuan 1 specimen is represented by a partial mandible and dentition, limited axial remains, portions of all long bones as well as some hand and foot bones. It was discovered in the Tianyuandong, a.k.a. Tianyuan Cave near Zhoukoudian, China. Radiocarbon dating of faunal remains from the same stratigraphic level indicate the Tianyuan 1 remains are at most 39,000 years old.

Sunghir 1 is also a partial skeleton, but it is not from China. In fact, Sunghir was found in a site on the outskirts of a Russian city called Vladimir. It has also been radiocarbon dated. It is roughly 23,000 years old. The interesting thing about Sunghir 1 is that it was excavated with an arrangements of beads sewn onto clothing that was wrapped around the feet — which is interpreted as evidence of footwear.

Trinkhaus and Shang compared Tianyuan 1 and Sunghir 1 foot phalanges to phalanges of archaic humans: Neandertals, humans from the Middle and Upper Paleolithic. They also compared them to foot bones from modern humans: Pueblo Indians, Inuits, and European Americans. The comparison involved the measurement of the cross-sectional area of the phalanges, and looked for the amount of torsion caused by the force of not wearing shoes. This value was coined the polar moment.

The results of the polar moments of area versus the natural log of phalangeal length times body mass is represented to your right. As you can see Tianyuan 1 and Sunghir 1 fall within the range of Inuit and European Americans. But, some European Americans and Inuits also exhibit the same polar moment as Neandertals and archaic humans from the Middle and Upper Paleolithic. Those that do have robust toes could have been non-shoe wearers, they still exist — believe it or not!

If the graph is making your mind spin, check out this photographic array of the Tianyuan 1 and Sunghir 1 phalanges compared to robust, presumably non-shoe wearing human ancestors, Qafzeh 8 and Kiik-Koba 1, a Neandertal. You don’t need fancy pants charts to see how narrow and delicate the Tianyuan 1 and Sunghir 1 bones are compared to Qafzeh 8 and Kiik-Koba 1. But note that bones are not resized to the same scale. Why not?

It is really hard to infer a behavior from one measurement, but I’m pretty convinced. So people were wearing shoes 10,000 years earlier than previously assumed from indirect evidence — definately plausible. People were living in extreme environments for hundreds of thousands of years and needed to protect their feet from the elements!

My most pressing issue is why the bones weren’t adjust to scale in this photo. If they were, we would have a better comparative framework to make the visual assessment ourselves. What if the two TY1 phalanges are longer than the KK1 phalanges? They sure appear to be. If they scaled them down to the length of KK1 phalanges, and the TY1 phalanges appeared to be just as wide as KK1, then Trinkhaus and Shang have a problem. It’s really simple to do. A couple minutes on Photoshop would do the trick. So long as Trinkhaus and Shang  provided the normal photo alongside the scaled photo, there would be no worries of manipulation.

TRINKAUS, E., SHANG, H. (2008). Anatomical evidence for the antiquity of human footwear: Tianyuan and Sunghir. Journal of Archaeological Science, 35(7), 1928-1933. DOI: 10.1016/j.jas.2007.12.002

TRINKAUS, E. (2005). Anatomical evidence for the antiquity of human footwear use. Journal of Archaeological Science, 32(10), 1515-1526. DOI: 10.1016/j.jas.2005.04.006

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