Paleolithic

Scientific Racism

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The site’s been quiet in 2017, with little time to blog on top of my regular professional responsibilities, and of course watching the fascist smoke rising from the garbage fire of our 45th presidential administration with horrified disbelief. At work, my two new classes are keeping me plenty busy, and their content is quite distinct – one is on the archaeological record of Central Asia, the other centers around Homo naledi to teach about fossils. But by complete accident, examples of scientific racism came up in the readings for each course last week.

scientific-racism

Scientific racism refers to using data or evidence from the biological and social sciences to support racist arguments, that one racial group is better or worse than another group; the groups of course, are culturally determined rather than empirically discrete biological entities. This evidence is often cherry-picked, misinterpreted, and/or outright weak. Nicolas’ Wade’s 2014 A Troublesome Inheritance is a recent example of such a work. The book’s racial claims amount to nothing more than handwaving, and so egregious is the misrepresentation of genetic evidence that nearly 150 of the world’s top geneticists signed a letter to the editor rebuking Wade for “misappropriation of research from our field to support arguments about differences among human societies.” Wade’s book has no place in scientific discourse, but then almost anyone can write a book as long as a publisher thinks it will sell.

In addition to the outright misrepresentation of scientific evidence to support racist arguments, another manifestation of scientific racism is the influence of cultural biases in the interpretation of empirical observations. This may be less malicious than the first example, but is equally dangerous as it more tacitly supports systemic and pervasive racism. And this brings us to my classes’ recent readings.

First was a reference to the “Movius Line” in a review of the Paleolithic record of Central Asia (Vishnyatsky 1999) for my prehistory class. Back in the 1940s Hallum Movius, archaeologist and amazing-name-haver, noticed a distinct geographic pattern in the distribution of early stone tool technology across the Old World: “hand-axes” could be found at sites across Africa and western Eurasia, while they were largely absent from East Asian sites, which were dominated by more basic stone tools.

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Movius’ illustration of the distribution of Early Paleolithic technologies. From Fig. 1 in Dennell (2015).

Robin Dennell (2016) provides a nice review of how Movius’ personal, culturally influenced perception of China colored his interpretation of this pattern. Movius read this archaeological evidence to mean that early East Asian humans were unable to create the more advanced technology of the west, a biological and cognitive deficiency resulting from cultural separation: “East Asia gives the impression of having acted (just as historical China and in sharp contrast with the Mediterranean world) as an isolated and self-sufficient area, closed to any major human migratory wave” (Movius 1941: 86, cited in Dennell 2015). Racial and cultural stereotypes about East Asia directly translated to his interpretation of an archaeological pattern.

This type of old school scientific racism also arose in a review of endocasts (Falk, 2014) for my Homo naledi class. Endocasts are negative impressions or casts of a space or cavity, and comprise the only direct evidence of what extinct animals’ brains looked like. So to see how the structure of the brain has changed over the course of human evolution, scientists can search for the impressions of important brain structures in fossil human endocasts. Falk (2014) reviews one of the most famous of these structures – the “lunate sulcus” – which was used as evidence for reorganization of the hominin brain for nearly 100 years. In the early 20th century, anatomist and anthropologist GE Smith (not GE Smith from the Saturday Night Live Band)  thought he’d identified the human homologue of a groove that in apes separates the parietal lobe from the visual cortex. In humans, however, this groove was positioned more toward the back of the brain, which Smith interpreted as an expansion of an area relating to advanced cognition.

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The back of the brain, viewed from the left, of a chimpanzee (left) and two humans, the red line illustrating the Affenspalte or lunate sulcus (Fig. 1 from Falk 2014, which was modified from Smith 1903). The middle one also might be a grumpy fish.

It turns out that the lunate sulcus does not actually exist in humans, as the grooves identified as such are not structurally or functionally the same as the lunate sulcus in apes (Allen et al., 2006). Nevertheless, given what Smith thought the lunate sulcus was, it’s tragic to read his interpretations of human variation: “resemblance to the Simian [ape] pattern… is not quite so obvious…. in European types of brain….” (Smith 1904: 437, quoted in Falk 2014). The human condition for this trait was for it to be located in the back, reflecting an expansion of the cognitive area in front of it, and this pattern was less pronounced, according to Smith, in non-European people’s brains. This interpretation reflects two traditions at the time: 1) to refer to racial ‘types,’ ignoring variation within and overlap between groups, as well as 2) the prevailing wisdom that Europeans were more intelligent or advanced than other geographical groups.

ResearchBlogging.orgAnecdotes such as these may seem like mere scientific and historical curios, but they should serve as important reminders both that science can be accidentally guided by cultural values, or intentionally used for malevolent ends. Misconceptions and errors of the past shouldn’t be erased, but rather touted so that we don’t repeat mistakes that can have major consequences in our not-so-post-racial society.

References

Allen JS, Bruss J, & Damasio H (2006). Looking for the lunate sulcus: a magnetic resonance imaging study in modern humans. The anatomical record. Part A, Discoveries in molecular, cellular, and evolutionary biology, 288 (8), 867-76 PMID: 16835937

Dennell, R. (2016). Life without the Movius Line: The structure of the East and Southeast Asian Early Palaeolithic Quaternary International, 400, 14-22 DOI: 10.1016/j.quaint.2015.09.001

Falk D (2014). Interpreting sulci on hominin endocasts: old hypotheses and new findings. Frontiers in human neuroscience, 8 PMID: 24822043

Vishnyatsky L (1999). The Paleolithic of Central Asia. Journal of World Prehistory, 13, 69-122.

What do capuchin stone tools tell us about human evolution?

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A month ago at ESHE and now online in Nature, Proffitt and colleagues describe stone-on-stone smashing behavior among wild bearded capuchin monkeys (Sapajus libidinosus). The online paper includes a great video documenting the action; here’s a screenshot:

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Holding the rock with both hands just above head-level, the monkey prepares to crush its enemies. Which in this case are another rock stuck in a pile of more rocks.

In the fairly rare cases where non-human primates use stones, it’s for smashing nuts or something. But when these capuchins see a stone they don’t just see a smasher, they see a world of possibilities* – why use a rock to break a rock, when you could use it to break a heart? So this group of capuchins is unique in part because they’ve been documented to use stones for many purposes.

Now why on earth a monkey would use one rock to break another rock is anyone’s guess. In human evolution, the purpose was to break off small, sharp flakes that could be used to butcher animals or work plants. Proffitt et al. did observe small flakes being removed when capuchins pounded rocks, but the monkeys showed little interest in this debitage, other than using it to continue smashing stuff. More curiously, the monkeys frequently lick the rock after hammering at it:

screen-shot-2016-10-20-at-7-56-44-am

Mmm, rocks.

Proffitt et al. venture that maybe these monkeys are doing this to ingest lichens or trace elements like silicon. This hypothesis merits further investigation, but what’s clear is that these monkeys’ lithics differ from the hominin archaeological record wherein the express purpose of breaking rocks is to make flakes.

What’s striking to me (pun intended) is the relative size of the rocks. These monkeys that weigh only 2-3 kg are lifting and smashing stones that weigh about half a kilogram on average. Because these stones are fairly large given the monkeys’ body size, they have to be lifted with two hands and brought down on a surface, a “passive hammer” technique. The earliest-known tools made by hominins, from the 3.3 million year old Lomekwi site in Kenya, are also pretty big. Weighing 3 kg on average but topping at 15 kg, these earliest tools would have required the same knapping technique as is used by these little monkeys (Harmand et al., 2015).

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Left: Cover of Nature vol. 521 (7552). Right: Bearded capuchin letting a pebble know who’s boss (link).

Why the big stuff at first? Did the earliest hominin tool-makers lack the dexterity to make tools from the smaller rocks comprising the later Oldowan industry? These creative capuchins could lead to predictions about the hand/arm skeleton of the Lomekwian tool-makers (testable, of course, only with fortuitous fossil discoveries). Capuchins are noted for their manual dexterity (Truppa et al., 2016) and have a similar thumb-index finger ratio to humans and early hominins (Feix et al. 2015), although they differ from humans in the insertion of the opponens muscle and resultant mobility of the thumb (Aversi-Ferreira et al., 2014). Maybe these tech-smart monkeys can tell us more about the earliest human tool-makers’ bodies than their brains.

ResearchBlogging.orgReferences

Aversi-Ferreira RA, Souto Maior R, Aziz A, Ziermann JM, Nishijo H, Tomaz C, Tavares MC, & Aversi-Ferreira TA (2014). Anatomical analysis of thumb opponency movement in the capuchin monkey (Sapajus sp). PloS one, 9 (2) PMID: 24498307

Feix T, Kivell TL, Pouydebat E, & Dollar AM (2015). Estimating thumb-index finger precision grip and manipulation potential in extant and fossil primates. Journal of the Royal Society, Interface, 12 (106) PMID: 25878134

Harmand S, Lewis JE, Feibel CS, Lepre CJ, Prat S, Lenoble A, Boës X, Quinn RL, Brenet M, Arroyo A, Taylor N, Clément S, Daver G, Brugal JP, Leakey L, Mortlock RA, Wright JD, Lokorodi S, Kirwa C, Kent DV, & Roche H (2015). 3.3-million-year-old stone tools from Lomekwi 3, West Turkana, Kenya. Nature, 521 (7552), 310-5 PMID: 25993961

Proffitt, T., Luncz, L., Falótico, T., Ottoni, E., de la Torre, I., & Haslam, M. (2016). Wild monkeys flake stone tools Nature DOI: 10.1038/nature20112

Truppa V, Spinozzi G, Laganà T, Piano Mortari E, & Sabbatini G (2016). Versatile grasping ability in power-grip actions by tufted capuchin monkeys (Sapajus spp.). American Journal of Physical Anthropology, 159 (1), 63-72 PMID: 26301957

*well, at least four uses given by Proffitt et al.: mating display, aggression, food-crushing, and digging.

eFfing #FossilFriday: toolmakers without tools?

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Matt Skinner and colleagues report in today’s Science an analysis of trabecular bone structure in the hand bones of humans, fossil hominins and living apes. Trabecular bone, the sponge-like network of bony lattices on the insides of many of your bones, adapts during life to better withstand the directions and amounts of force it experiences. This is a pretty great property of the skeleton: bone is organized in a way that helps withstand usual forces, and the spongy organization of trabeculae also keeps bones fairly lightweight. Win-win.

An X-ray of my foot. Note that most of the individual foot bones are filled with tiny 'spicules' (=trabeculae) of bone. Very often they have a very directed, or non-random, orientation, such as in the heel.

An X-ray of my foot. The individual foot bones are filled with narrow spicules (=trabeculae) of bone. Very often they have a directed, or non-random, orientation: in the calcaneus, for instance, they are oriented mostly from the heel to the ankle joint.

This adaptive nature of trabecular bone also means that we can learn a lot about how animals lived in the past when all they’ve left behind are scattered fossils. In the present case, Skinner and colleagues tested whether tool use leaves a ‘trabecular signature’ in hand bones, looking then for whether fossil hominins fit this signature. Their study design is beautifully simple but profoundly insightful: First, they compared humans and apes to see if the internal structure of their hand bones can be distinguished. Second, they tested whether these differences accord with theoretical predictions based on how these animals use their hands (humans manipulate objects, apes use hands for walking and climbing). Third, they determined whether fossil hand bones look more like either group.

Comparison of first metacarpals (the thumb bone in your palm) between a chimpanzee (left), three australopithecines, and a human (right). In each, the palm side is to the left and the wrist end of the bone (proximal) is down. Image by Tracy Kivell, and found here.

Looking at the image above, it’s difficult to spot trabecular differences between the specimens with the naked eye. But computer software can easily measure the density and distribution of trabecular bone from CT scans. With these tools, researchers found key differences between humans and apes consistent with the different ways they use their hands. Neandertals (humans in the past 100 thousand years or so) showed the human pattern, not unexpected since their bones look like ours and they used their hands to make tools and manipulate objects like we do.

What’s more interesting, though, is that the australopithecines, dating to between 1.8-3.0 million years ago, also show the human pattern. This is an important finding since the external anatomy of Australopithecus hand bones shows a mixture of human- and ape-like features, with unclear implications for how they used their hands. Their trabecular architecture, reflecting the forces their hands experienced in life, is consistent with tool use.

This is a very significant finding. Australopithecus africanus fossils from Sterkfontein aren’t associated with any stone tools; bone tools are known from Swartkrans, though it is unclear whether Australopithecus robustus or Early Homo from the site made/used these. In addition, in 2010 McPherron and colleagues reported on a possibly cut-marked animal bone from the 3.4 million year old site of Dikika in Ethiopia, where Australopithecus afarensis fossils but no tools are found. Skinner and colleagues’ results show that at the very least, South African Australopithecus species were using their hands like tool-makers and -users do.

This raises many fascinating questions – were australopithecines using stone tools, but we haven’t found them? Were they using tools made of other materials? What do the insides of Australopithecus afarensis metacarpals look like? What I like about this study is that it presents both compelling results, and raises further (testable) questions about both the nature of the earliest tools and our ability to detect their use from fossils.

Kazakhstan Paleolithic fieldwork: Valikhanova

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Last week, I left my home in Astana for southern Kazakhstan, to rendezvous with researchers based in Kazakhstan, the United States and Germany. This is the beginning of a collaborative effort to understand the underappreciated importance of Kazakhstan in hominin evolution.

Post-fieldwork meal. From foreground clockwise: Zhaken Taimagambetov (1), Tyler (2), Saya (1), Jason (2), Adam (3), Radu (4), Mica (2), Kat (5), Katie (2), and Rinato (1). Not pictured: Me (6) and Jean-Marc (1). Numbers indicate school affiliations, at the end of the post.

We just returned from a brief stint of soil sampling at, and site surveying around, the Paleolithic site of Valikhanova, near the town of Zhanatas. This site was excavated decades ago, and has yielded a number of stone tools interpreted as transitional between Middle and Upper Paleolithic industries. This is a fascinating period for ‘modern’ human origins, but unfortunately the site has not yielded any human fossils to the best of my knowledge.

Valikhanova. The excavation site is the layered earth exposure on the right, our camp site on the left.

But there are other important questions that can be asked about the nature of the site and its inhabitants. First, the geological layers (“strata”) of the site have not been reliably dated, so soil samples were collected to be analyzed by a dating technique called optically stimulated luminescence (this is the work of Dr. Kat Fitzsimmons). Second, aspects of climate and ecology can be inferred from soil chemistry, which is the focus of team members from Colorado State University. Combining this information, we can begin to understand when and why humans (Neandertal and/or more ‘modern’ looking) inhabited the area – e.g., was it only between major glacial periods, how much time does the site span, etc?

And it’s a pretty amazing area. The site is nestled in a depression, creating an ecosystem somewhat protected from harsh winds and temperatures blowing around surrounding the mountains. That said, the night we arrived we were welcomed by extremely high-speed winds and heavy rains. My tent was the only casualty of the storm, forcing me to flee to the comforting confines of our sturdy truck and cups of vodka. The storm was short lived, and soon the sky opened up to a panoramic harlequin sunset.

Palette after the storm. Left to right covers from West to East. The excavation and North are at the center.

Also there was a rainbow.

My main activity here was survey, the search for other places that could potentially yield fossil and additional cultural materials. Survey basically involves a fairly targeted scouring of a landscape, searching for specific features. Our survey took us over and across gorgeous landscapes. We found a number of possible fossil/artifact accumulations and possible caves/rock shelters for future investigation, but no human fossils turned up (this was not terribly surprising, as human fossils are quite rare).

Atop one big hill, Drs. Jason LaBelle and Adam Van Arsdale discuss one of many stone tools we found littering the area around Valikhanova.

One neat surprise did come when scanning the ground above a rocky outcrop over a filled-in cave. At first glance, I seem to be holding some kind of a jaw bone fragmentwith two teeth. Close inspection shows this just to be a rock with a coincidentally-molar-like calcification. Bummer. However, we were able to trick one expert into thinking for a minute that we found some kind of pig or other mammal fossil.

Fossil bovid, equid or suid? Meganthropus?! Just a rock? Osteology students & paleontologists, beware faux-ssils…

We’re briefly back in Almaty to recharge, and on Tuesday we’ll head out to explore Charyn Canyon for a few days. Stay tuned for more about our adventures!

*Affiliations from Fig. 1 above:
1. Kazakh National University, 2. Colorado State University, 3. Wellesley College, 4. Römisch-Germanisches Zentralmuseum, 5. Max Planck Institute. 6. Nazarbayev University.

How old is the Acheulian tool industry and why does it matter?

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Two views of an Acheulian handaxe adorn the cover of this week’s Nature (right). Always happy to see paleoanthropology stuff be classy, front-page news. The cover highlights Christopher Lepre’s and colleagues’ announcement of what may be the oldest Acheulian tools known.

To recap stone tools: The first good evidence of tool use by humans’ ancestors are the Oldowan lithics from the 2.6 million year old site of Gona in Ethiopia (Semaw et al. 2003). McPherron and others (2010) reported 2 possibly-cut-marked animal bones from the 3.4 million-year old site of Dikika; but this latter evidence is a bit too scant for us to really be sure our ancestors had adopted technology this early. Anyway, the Oldowan was a very basic tool industry, consisting largely of crude flakes taken off cobbles. It may sound lame, but even the most basic stone-tool-making requires some skills, trust me, it’s kinda hard. So stone tools appear roughly 2.5 million years ago, which is also about the time that we have fossils that might document the earliest members of our genus Homo. Sweet.

The legend goes that the next technological revolution doesn’t come until about 1 million years later – until around 1.5 million years ago, stone tools were quite basic. But after a while we start seeing these “handaxes” or “bifaces” (cuz flakes are removed from both of the core’s faces; see above) that have become kind of the hallmark of what’s termed the Acheulian industry. I’m sure there are other key indicators but what do I know, I’m not an archaeologist. Arguably, the rise of the Acheulian from its humble Oldowan beginnings is a milestone in human cognitive evolution – a more complex tool should require a more complex brain, right? Lepre and team announced today that they have some Acheulian handaxes from the Kenyan site of Kokiselei-4, dating to 1.76 million years ago. The authors draw two conclusions: 1) the Acheulian (and thereby more advanced cognition) is a few hundred thousand years older than previously thought, and 2) the co-occurrence of Acheulian and Oldowan tools at this time indicates the presence of contemporaneous human species with different cognitive capabilities.
Now what’s a bit odd here is that the presence of handaxes among otherwise Oldowan assemblages is not a new or unique thing. In her archaeological research at Olduvai Gorge in Tanzania, Mary D Leakey distinguished some assemblages as “Developed Oldowan.” Here’s a relevant blurb from a study by Y. Kimura (2002: 292-293):
“Leakey recognized two distinctive industries, Oldowan and Acheulian, from Bed I through Bed III at Olduvai. The former was characterized by the presence of various choppers and attributed to Homo habilis sensu lato, whereas the latter was traditionally defined to contain bifaces more than 40-60% of the tools, and attributed to H. erectus sensu lato.
The Oldowan was then classified into Oldowan (1.87-1.65 mya) and Developed Oldowan (1.65-0.6 mya) based on the increased light-duty tools, spheroids and bifaces in the latter. The Developed Oldowan coexisted with Acheulian” (emphasis mine)
So the co-occurrence of Oldowan (i.e. choppers) and Acheulian (some handaxes) is known from other sites, albeit not until around 1.5 million years ago. Too bad I’m not an archaeologist nor know more about lithics, because I wish I could put the new Kokiselei-4 assemblage into this context – just how is it different from “Developed Oldowan”? As John Hawks pointed out before I did, “developed Oldowan” doesn’t appear in the Lepre et al. discussion. Hrm. Then they make this statement:

“Homo erectus is traditionally thought to be the first hominin to disperse from Africa, yet the oldest known out-of-Africa fossil hominin sites lack stone tools or preserve only Oldowan-style artefacts. … Our data indicate that the earliest development of the Acheulian occurred in Africa at 1.76 [million years] ago and was contemporaneous with or perhaps pre-dated the earliest hominin dispersals into Eurasia (Lepre et al. 2011: 84).

They then go on to suggest that two contemporaneous species lived in Africa in the early Pleistocene – one of these species invented the Acheulian and stayed in Africa, while the other species was too dumb to make anything beyond Oldowan, and instead these dullards left Africa to colonize the rest of the world. This silly scenario seems to stem from an under-appreciation of what Dmanisi demonstrates (possibly since the recent dating paper by Reed Ferring and others only came out a few months ago, probably after the Lepre et al. paper was in press). The Dmanisi fossils establish that hominins more primitive than later Homo erectus (Rightmire et al. 2006) had dispersed into Eurasia by around 1.85 million years ago (if not earlier), with mere Oldowan technology (Mgeladze et al. 2010, Ferring et al. 2011). So Lepre et al.’s claim that the earliest Acheulian “was contemporaneous or perhaps pre-dated” the first out-of-Africa dispersals just isn’t true. And without that, there’s no support for the silly scenario of a smart, techno-savvy but stationary species being contemporaneous with a colonizing but less crafty-and-cunning species.
ResearchBlogging.org
It’s really cool if the Kokiselei-4 tools truly represent the earliest record of the Acheulian. But, it should be clear by now that we can’t simply equate technology and taxonomy. So how old is the Acheulian and why does it matter? I’m fine with a 1.76 million year date, but I also don’t think it matters too much. (sorry to be so Dmanisi-centric)
References
Ferring, R., Oms, O., Agusti, J., Berna, F., Nioradze, M., Shelia, T., Tappen, M., Vekua, A., Zhvania, D., & Lordkipanidze, D. (2011). From the Cover: Earliest human occupations at Dmanisi (Georgian Caucasus) dated to 1.85-1.78 Ma Proceedings of the National Academy of Sciences, 108 (26), 10432-10436 DOI: 10.1073/pnas.1106638108
Kimura, Y. (2002). Examining time trends in the Oldowan technology at Beds I and II, Olduvai Gorge Journal of Human Evolution, 43 (3), 291-321 DOI: 10.1006/jhev.2002.0576
Lepre, C., Roche, H., Kent, D., Harmand, S., Quinn, R., Brugal, J., Texier, P., Lenoble, A., & Feibel, C. (2011). An earlier origin for the Acheulian Nature, 477 (7362), 82-85 DOI: 10.1038/nature10372
McPherron, S., Alemseged, Z., Marean, C., Wynn, J., Reed, D., Geraads, D., Bobe, R., & Béarat, H. (2010). Evidence for stone-tool-assisted consumption of animal tissues before 3.39 million years ago at Dikika, Ethiopia Nature, 466 (7308), 857-860 DOI: 10.1038/nature09248
Mgeladze, A., Lordkipanidze, D., Moncel, M., Despriee, J., Chagelishvili, R., Nioradze, M., & Nioradze, G. (2011). Hominin occupations at the Dmanisi site, Georgia, Southern Caucasus: Raw materials and technical behaviours of Europe’s first hominins Journal of Human Evolution, 60 (5), 571-596 DOI: 10.1016/j.jhevol.2010.10.008
Rightmire, G., Lordkipanidze, D., & Vekua, A. (2006). Anatomical descriptions, comparative studies and evolutionary significance of the hominin skulls from Dmanisi, Republic of Georgia Journal of Human Evolution, 50 (2), 115-141 DOI: 10.1016/j.jhevol.2005.07.009
Semaw, S., Rogers, M., Quade, J., Renne, P., Butler, R., Dominguez-Rodrigo, M., Stout, D., Hart, W., Pickering, T., & Simpson, S. (2003). 2.6-Million-year-old stone tools and associated bones from OGS-6 and OGS-7, Gona, Afar, Ethiopia Journal of Human Evolution, 45 (2), 169-177 DOI: 10.1016/S0047-2484(03)00093-9

Neandertal terminal biogeography

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How late did Neandertals persist in the Late Pleistocene? Two papers out this week discuss the dates of the latest Neandertals in western Asia.

Pinhasi and colleagues (2011) stress the importance of directly dating Late Pleistocene human-ish fossils. There are numerous techniques used to estimate the ages of the fun stuff we find underground. For fairly old fossils like australopithecines, perhaps the most reliable radiometric method is Argon-Argon, though this requires the fossils to be relatable to volcanic sediments whose argon levels can be measured. The point is that dates of burial are often not estimated from the fossil materials themselves, but rather the sediments and such surrounding the fossil of interest. But younger fossils (than say 50,000) preserve some of the bone’s original carbon -allowing age estimates of the fossils themselves by radiocarbon dating.

Pinhasi and colleagues note that while seven separate Neandertal specimens from across Europe and western Asia have been directly dated to be younger than 36 thousand years, these dates may be underestimates. In other words, Neandertals may not have lived after 40 thousand years. To this end, these researchers directly re-dated the infant Neandertal from Mezmaiskaya Cave in Russia, and estimate the poor lad to have died around 42-44 thousand years ago. The authors predict that future direct redating of other Neandertals will show Neandertals to have disappeared by 40 thousand years ago, and that they would have overlapped in time with more modern-looking humans either minimally or not at all. If only there were more information on the latest dates for Middle Paleolithic people!

Lucky me, in tomorrow’s Science, Ludovic Slimak and colleagues report on Mousterian tools dating to 32-34 thousand years ago, from the site of Byzovaya Cave “in the western foothills of the Polar Urals” (Slimak et al. 2011: 841). “POLAR!” The site is way further north than any site with Neandertal bones like Mezmaiskaya and Okladnikov, which is pretty impressive. But, there are no human remains associated with the tools, so we don’t know who made them. To what extent do these finds address Pinhasi’s and others’ contention of no Neandertals after 40 thousand years ago?

Slimak and colleagues carbon-dated animal bones that were butchered with the Mousterian tools, which were allegedly made only by Neandertals. There is a major problem with the wide-held assumption that Mousterian (Middle Paleolithic) tools were made only by Neandertals, whereas Upper Paleolithic industries beginning with the Aurignacian were made only by humans. This goes along with people’s wont to make a connection between stone tool ‘culture’ and biologically determined, phylogenetically significant behavioral capacities. But of course, we know biology doesn’t determine behavior, and so there’s no reason to assume [Mousterian:Neandertal::Aurignacian:’Modern’ Human]. Where Mousterian remains have been associated with diagnostic skeletal remains, they are Neandertal. But the Aurignacian, so far as I know, is not associated with diagnostic fossils – we can’t say for certain who made it. Plus we know Neandertals were doing something kooky, yet logical in some sort of cognitively complex way, with bird feathers in Italy 44 thousand years ago (Peresani et al. 2011). So the Byzovaya stone tools may demonstrate a late, northern holdout of Neandertals, but then they could simply mean that the new technology either hadn’t arrived or hadn’t been successful in the far reaches of sub-Artic Pleistocene humanity.

If the latter is the case and Pinhasi & team’s hypothesis that Neandertals didn’t coexist in time and space (or did only minimally) holds, then the old assumption of Mousterian = Neandertal becomes dubious for other sites with Mousterian tools but no diagnostic fossils. This would also beg the question of the role of modern humans in the Neandertal demise – did the Neandertals disappear and open a niche for other groups of people (‘moderns’)?

So how were Neandertal populations distributed through space and time in their latest days? I dunno! But for the moment I suppose I’d be surprised if no fossils with Neandertal morphology turn out to be younger than 40 thousand years as suggested by Pinhasi and co. But then I could be wrong.

ResearchBlogging.org
References
Hoffmann, A., Hublin, J., Hüls, M., & Terberger, T. (2011). The Homo aurignaciensis hauseri from Combe-Capelle – A Mesolithic burial Journal of Human Evolution DOI:10.1016/j.jhevol.2011.03.001

Peresani, M., Fiore, I., Gala, M., Romandini, M., & Tagliacozzo, A. (2011). Late Neandertals and the intentional removal of feathers as evidenced from bird bone taphonomy at Fumane Cave 44 ky B.P., Italy Proceedings of the National Academy of Sciences, 108 (10), 3888-3893 DOI:10.1073/pnas.1016212108

Pinhasi R, Higham TF, Golovanova LV, & Doronichev VB (2011). Revised age of late Neanderthal occupation and the end of the Middle Paleolithic in the northern Caucasus.Proceedings of the National Academy of Sciences of the United States of America PMID:21555570

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