Homo naledi in a lawn chair

It is a great relief that Homo naledi, a most curious critter, was announced to the world on Thursday. I’ve been working on these fossils since May 2014, and it was really hard to keep my trap shut about it for over a year.

Homo naledi on my mind, and phone, all year.

Homo naledi on my mind, and the lock screen on my phone, all year. CT rendering of cranium DH3, top is to the left and front is to the top.

I was in London for the ESHE conference last week when **it hit the fan, and so I got to attend a small press conference from the paper’s publisher, eLife, for the announcement.

eLife press conference last Thursday. From left to right: Will Harcourt-Smith, Matthew Skinner, Noel Cameron, Alia Gurtov and Tracy Kivell.

eLife press conference last Thursday. From left to right: friends and colleagues Will Harcourt-Smith, Matthew Skinner, Noel Cameron, Alia Gurtov and Tracy Kivell.

I had just flown in from Kazakhstan, and was presenting some recent work on the evolution of brain growth (I’ll write a post about it soon, promise), so it was a bit hard to appreciate the gravity of the announcement. Although the awesome spread in National Geographic did help it sink in a bit.

Really blurry photo of Markus Bastir holding up the heaviest copy of National Geographic ever.

I’m wending my way back to Kazakhstan now, but in the coming weeks I will try to post more about these fossils, the project, and specifically what I’m working on.

Until then, I’d like to point out how much information is freely and easily available to the entire world about these fossils. The paper, full-length and filled with excellent images of many of the specimens and reconstructions, is available for free online here. In addition, you can download 3D surface scans of over 80 of the original fossils on MorphoSource, also totally free. Everything about this scientific discovery and its dissemination is unprecedented – the sheer number of fossils and the ease of access with which literally everyone (well, with an internet connection) can access this information has never occurred before. This is the way paleoanthropology should be. Hats off to Lee Berger and the other senior scientists on the project for making such a monumental resource available to all.

ResearchBlogging.orgBerger LR, Hawks J, de Ruiter DJ, Churchill SE, Schmid P, Delezene LK, Kivell TL, Garvin HM, Williams SA, DeSilva JM, Skinner MM, Musiba CM, Cameron N, Holliday TW, Harcourt-Smith W, Ackermann RR, Bastir M, Bogin B, Bolter D, Brophy J, Cofran ZD, Congdon KA, Deane AS, Dembo M, Drapeau M, Elliott MC, Feuerriegel EM, Garcia-Martinez D, Green DJ, Gurtov A, Irish JD, Kruger A, Laird MF, Marchi D, Meyer MR, Nalla S, Negash EW, Orr CM, Radovcic D, Schroeder L, Scott JE, Throckmorton Z, Tocheri MW, VanSickle C, Walker CS, Wei P, & Zipfel B (2015). Homo naledi, a new species of the genus Homo from the Dinaledi Chamber, South Africa. eLife, 4 PMID: 26354291

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Online primate anatomy lab exercise

I work at a very freshly opened University in Kazakhstan, a school so young that we will not graduate our first class for another year. I came here for the exciting prospects of helping establish an anthropology program, but there are lots of challenges, too. One of the biggest I face as an educator is that infrastructure and other physical materials are still in the process of coming together. Simply put: we don’t got no bones! This is especially troublesome when teaching human evolution, an anatomy-oriented class in which students really can benefit from examining physical bones and casts of fossils first-hand.

So until we get our badass laboratory of anthropological sciences, I’ve put together a lab activity using the Kyoto University Primate Research Institute’s online database of CT scans (blogged about before here and here). The purpose of this activity is to show students ‘virtual’ primate skeletons that they can examine, look inside, and even measure. The KUPRI CT viewers allow students to identify structures, rotate and orient the skeletons, and measure using a handy grid function. While I love this resource, I’ll admit that the program can be a bit unwieldy, and so it takes some time to figure out how to use well.

Measure that gibbon radius!

Measure that gibbon radius!

In this exercise, students will measure cranial width, femur head diameter, and maximum length of the humerus, radius, femur, and tibia. Cranium width is then used to estimate cranial capacity (based on chimps, from Neubauer et al., 2012); femur head diameter allows estimation of body mass (using anthropoid regressions from Ruff, 2003); and the limb dimensions are used to calculate various indices. The class as a whole will look at apes and monkeys, for comparison with published values for other species. Then we’ll gather ’round the campfire to talk about our feelings about it. I’m hoping it will get them familiar with the basic anatomy and names of bones, some experience collecting data, and some understanding of variation between different species.

Best of all, each student will write up their ‘analysis’ on the NU Bioanthro Student blog next week. Stay tuned to see their results!

So, I’m attaching the exercise to this post – feel free to use or modify. If you have any other similar exercises, the rest of the internet and I would be happy to hear about them

Download me: Primate CT lab! [updated 06 Feburary, to fix issues with brain and body size estimation equations in previous version]

One more great bioanthro resource

Following up on yesterday’s post containing links to various online data and resources, Dr. Rebecca Jabbour brought the Human Origins Database to my attention today. As stated on the database’s home page:

Currently the Human Origins Database contains the measurements and skeletal element information present in the Koobi Fora Research Project. Volume 4: Hominid Cranial Remains by Bernard Wood (1991). In addition, a complete inventory of skeletal elements present for the chimpanzee and gorilla collections at the Powell-Cotton Museum is included, along with annotated data sheets providing information on epiphyseal fusion, element condition, etc.

Here’s a taste of the Powell-Cotton chimpanzee catalog & maturation info:

You have to register to access the database – which you should do since it’s free and appears immensely useful. Enjoy!

Online skeletal and dental datasets (links links links!)

The TM 1517a fossil, from here

Jean Jacques Hublin has a commentary [1] in the current issue of Nature, about making fossils available for scanning, digital replication, and ultimately hopefully open dissemination. As Hublin points out, it’s a bit ridiculous that a fossil is a rare enough thing as it is, but even after their discovery, fossils “can become unreachable relics once they are in storage.” Fortunately, Hublin goes on to point to online collections that are available to anyone interested. Somewhat ironically, the article about free-ish data is behind a paywall, so here are the resources Hublin describes:

  • The Ditsong CT Archive, created by the collaboration of Hublin’s group at Max Planck and the Ditsong (formerly Transvaal) Museum in South Africa, which contains digitized hominin fossils from the site of Kromdraai (see also [ref 2]). Check out the type specimen of Paranthropus robustus, from this site, above!
  • You can download CT scans of the Skhul V early human fossil, thanks to the Harvard Peabody Museum.
  • Wanna see the the oldest possible animal embryos, early humans, insects, and other crazy fossils? Check out the European Synchrotron Radiation Facility’s microCT database.
  • Get free CT scans of 2 human skulls, thanks to the Virtual Anthropology program at the University of Vienna.
  • Finally, the NESPOS initiative is a large repository of Pleistocene hominin fossil scans, which I somehow don’t know enough about.

In addition to these sources, here are 2 other datasets that are pretty badass:

ResearchBlogging.orgI haven’t had much opportunity to look into these datasets Hublin pointed out, but they look promising. If you know of other good resources, please do share!

References
[1] Hublin, J. (2013). Palaeontology: Free digital scans of human fossils Nature, 497 (7448), 183-183 DOI: 10.1038/497183a

[2] Skinner MM, Kivell TL, Potze S, & Hublin JJ (2013). Microtomographic archive of fossil hominin specimens from Kromdraai B, South Africa. Journal of human evolution, 64 (5), 434-47 PMID: 23541384

Open wide for open access: chimpanzee tooth eruption

Two anthropology papers came out yesterday in advance print at the Proceedings of the National Academy of Sciences. I’d like first to draw your attention to the fact that they’re open access – normally such scientific papers are behind a paywall, but these two can be obtained by anyone (well, anyone with internet). One is about the chronology and nature of Acheulean technology at the 1.7-1.0 mya site of Konso in Ethiopia. The other, and the subject of this post, is about life history in wild chimpanzees from Uganda.

Tanya Smith and colleagues analyzed behavior of chimps and photographs of chimps’ erupting first molars (“M1”) to determine a] the age at which these events happen in the wild (in this population at least), and b] whether M1 eruption is tightly linked with other important life history variables, such as the adoption of adult foods, as had previously been claimed. What an adorable study – check out figure 1 from the paper (right):

Figuring out age at M1 eruption in wild, healthy chimps is important because there has been debate about whether wild chimps actually erupt their teeth at as young of ages as they do in captivity – not natural conditions. This question has recently been investigated in a skeletal sample of wild chimps of known age, from Tai forest in Cote d’Ivoire (Zihlman et al. 2004, T Smith et al. 2010), but somehow these studies raised more questions than they answered (e.g. BH Smith and Boesch 2011). So TM Smith and colleagues decided to further address this question with photographic evidence of living, arguably healthy chimps. I’m kicking myself in the ass because I had this exact same idea a few months ago but had a bit too much on my plate to tacklet it at the time. Life.

Anyway, Smith and pals showed found that M1 eruption occurred anywhere from 2.8-3.3 years of age in their sample of 5 cuddly infants, consistent with estimates from captivity. I have to say I’m a bit surprised it wasn’t later (but what fun is science if it’s not surprising?). Of course, this is based on 5 infants from one population, so it could stand to be reinvestigated in other chimp populations, as the authors note; variation is, after all, key for evolution and a key problem for evolutionary biologists. Maybe I’ll get another crack at a photo-based eruption study after all…

Smith et al’s second task was to see how well age at M1 eruption coincided with other life history variables – this is supposed to be an important event, alleged to coincide with cessation of weaning and the adoption of adult foods. Moreover, since a mother is no longer nursing her infant, M1 eruption “should” also be roughly contemporaneous with a mother’s return to estrus cycling and subsequent re-pregnancy. Many infants were observed to begin eating adult-like foods prior to M1 eruption, around 3 years. Unexpectedly however, infants also nursed for a while even after M1 eruption. In fact, time spent nursing actually increased for a brief period around 3 years of age, possibly because their mothers’ milk was not as nutritious as at younger ages.

Now, what interests me most about this are possible implications for my research on the evolution of growth and life history. Many researchers have argued that extinct hominids, like the australopithecines, would have grown up relatively rapidly like apes, rather than slowly like humans. This claim has been based pretty much entirely on dental development, until my dissertation research. There, I’ve shown that one hominid, Australopithecus robustus, probably experienced greater jaw growth than humans prior to eruption of the M2. Now, if this hominid erupted its teeth as fast as apes, and grew more than humans, this implies really really high growth rates for A. robustus (that is, if we can extrapolate from the jaw to the overall body size).

ResearchBlogging.orgI’ll be working a bit more on this latter point in the near future. In the mean time, let’s hear it for bioanthro dominating open access today!

References
Smith BH, & Boesch C (2011). Mortality and the magnitude of the “wild effect” in chimpanzee tooth emergence. Journal of human evolution, 60 (1), 34-46 PMID: 21071064

Smith TM, Smith BH, Reid DJ, Siedel H, Vigilant L, Hublin JJ, & Boesch C (2010). Dental development of the Taï Forest chimpanzees revisited. Journal of human evolution, 58 (5), 363-73 PMID: 20416929

Smith, T., Machanda, Z., Bernard, A., Donovan, R., Papakyrikos, A., Muller, M., & Wrangham, R. (2013). First molar eruption, weaning, and life history in living wild chimpanzees Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.1218746110

Zihlman A, Bolter D, & Boesch C (2004). Wild chimpanzee dentition and its implications for assessing life history in immature hominin fossils. Proceedings of the National Academy of Sciences of the United States of America, 101 (29), 10541-3 PMID: 15243156

And so the plot thickens



These results suggest admixture between Denisovans or a Denisova-related population and the ancestors of East Asians, and that the history of anatomically modern and archaic humans might be more complex than previously proposed.


I’m sure it will turn out to be more complex still. Onward and upward!


Freely available online through the PNAS open access option.”
http://www.pnas.org/content/early/2011/10/24/1108181108.abstract


Sweet!


Here you go
Skoglund P and Jakobsson M. Archaic human ancestry in East Asia. Proceedings of the National Academy of Sciences in press. doi:10.1073/pnas.1108181108.