An Attempt At A Morphological Reassessment Of The Teshik-Tash Neandertal Child

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
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

7 thoughts on “An Attempt At A Morphological Reassessment Of The Teshik-Tash Neandertal Child

  1. “There’s been a lot of back and forth since the original publication on whether or not Teshik-Tash is really a Neandertal”. So Neanderthals and modern humans are totally separate species are they? Shouldn’t be too difficult to identify which it is then.

  2. Hi Terry,

    It gets a little dicey to differentiate the two when dealing with a subadult. Teshik-Tash is a child, one that doesn’t quite have the full subset of Neandertal traits due to its developmental immaturity. Since the fossil record of Neandertal children is pretty sparse (Teshik-Tash is the only Neandertal-looking child from Central Asia, and there aren’t that many European/Middle Eastern samples), it is hard to do a thorough comparison.

    But it does have some Neandertal traits. Look at the image of the cranium above. Notable features are the enlarged nostrils and unique foramen magnum. The current authors argue that these traits are not true manifestations of Neandertal traits, but byproducts of the reconstruction process and a bias towards making Teshik-Tash be a Neandertal. They do a whole lot of measurements and statistical analysis and conclude that Teshik-Tash resembles Upper Paleolithic humans — but some of the mtDNA says otherwise.

    Kambiz

  3. After reading the article I have to say I’m not very impressed. There is a certain strawmanish quality to the argument that Teshik-Tash doesn’t look like classic European Neandertals because there is a lot of variability in the Neandertal sample. Lots of Neandertals do not look like classic European Neandertals. Combined with the fact that they are using a lot of measurements that they didn’t take themselves and I have to wonder. Minor quibble, what person in their right mind would cite Garget 1989 and expect to be taken seriously?

  4. A baby hominid anything has a strong resemblance to an anatomically modern human – even a monkey. After all, the snout has not grown out yet, and all the rest of the bone shelves that allow us to differentiate between them and us – so, why not just let everything depend on the DNA? If it barks like a dog, it most likely is a dog – why get out of bed until it sounds like something else?

  5. Could the Denisova hominin help explain the differences? Also, I find it curious, that according to the human genome project, the chromosomes we have, that have dramatically different origin points, match our estimates (1mil & 600k years) of when Neanderthalis and Denisova split from our primary path. And furthermore, those chromosomes, from my laymans perspective are largely responsible for not only common “visual” traits but also genetic diseases that affect certain smaller portions of modern man.

    I mean, I can’t float, I have shorter shins then thighs, freckles, red hair, a heavy head, brow ridges, can’t eat fructose and I can grow muscles much bigger then my peers, sitting at a desk in an office all day. Quite a few of these things just do not make sense to me. Maybe I’m drawing links that don’t exist but I get surprised at how easy they are to draw, while none within the actual field of anthropology or archaeology (or even language) seem to be looking across fields.

    1. Senor Freebie,

      How astute of you and how anticipatory of the Neandertal genome project results. Are ye layman or are ye foreshadowing academia?

      Z-andertal

  6. Denisovan? Maybe nuclear DNA should take precedence over
    mitochondrial DNA sequencing when definitively determining heritage
    and inheritance. Morphology seems to be just that: shapes of bones
    at certain times of life that are determined as much by genetics as
    environment. Oh, the age old nature vs. nurture debate continues,
    but the nurture part should be viewed with the nature crucible.
    –James Zaworski excerpt from my blog: http://www.humanorigins.weebly com
    (human origins blog) January 7, 2010 (China time)

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