Upper Paleolithic

Marie-France Deguilloux and colleagues [1] present a short analysis of ancient mtDNA recovered from a Neolithic burial at Prissé-la-Charrière, between the Loire and Garonne valleys of western France.

The mtDNA sample in the end was only three individuals -- one haplogroup X2, one U5a and one N1a. Each is intriguing, as far as a single sequence can be, because all are rare or absent from France today. I think one shouldn't go far interpreting three samples, but they contribute to the view that Neolithic mitochondrial variation in Europe was very different from recent Europeans. The N1a and U5b sequences fit within the already-known Neolithic (and for U5a, Mesolithic) variation in central and northern Europe.

It is from the U5a that Deguilloux and colleagues make a point about possible Mesolithic population continuity.

Subhaplogroup U5b has also been encountered in German Neolithic remains from the Corded Ware Culture (Haak et al., 2008) and in the hunter-gatherers studied by Bramanti et al. (2009), although in both instances, the branches concerned were distinct from the U5b in the Prissé sample. It is, however, worth noting that haplogroup U5 has been encountered in surprising frequency in the hunter-gatherers studied by Bramanti et al. (2009) and could correspond to a Mesolithic heritage.

The story of N1a is that it was very common in the central European Neolithic, even though it is very rare today. That was first noted by Wolfgang Haak and colleagues [2], and has in subsequent years been joined by the observation that the pre-Neolithic hunter-gatherers had yet other common haplogroups. The population history of Europe was a lot more interesting than we suspected 10 years ago.

Deguilloux and colleagues attempt a conservative explanation for the frequencies of N1a in Neolithic samples:

The widespread distribution of the N1a lineage in Early and Middle Neolithic northwestern Europe may indicate genetic continuity from Mesolithic populations. This scenario would support a Mesolithic contribution to the earliest Neolithic of Atlantic Europe. This would imply that the N1a lineage was already common in indigenous north European populations and that the spread of the Neolithic was principally the result of cultural diffusion. Although so far the N1a lineage has not been encountered among late European hunter-gatherers in central and north Europe (Bramanti et al., 2009; Malmström et al., 2009), it is worth noting that less than half of the hunter-gatherers' paleogenetic data come indeed from the pre-Neolithic period (predating LBK expansion). Finally, no paleogenetic data currently exist for the Mesolithic period in Western Europe. This prevents any conclusion being drawn about N1a occurrence during the Mesolithic period in those regions.

I will note this -- the more that N1a is replicated across the Neolithic of Europe, the less and less likely that its subsequent vast reduction in frequency could result from genetic drift. When there was only one or two samples from Central Europe with high N1a, it was at least possible that this was a local founder population that did not spread its mtDNA diversity very far. If it were localized, even in the central Danube (a fairly big region) it might be possible to maintain that the later decline of N1a to its present low frequency had been due to population replacement.

Now N1a seems like a real marker of the LBK, spread widely into Western Europe. It may be, as Deguilloux and colleagues suggest, that it will be found at substantial frequencies in earlier samples somewhere in Europe. We do want some explanation for how it got to be common in this culture area.

Dienekes has written about the study. His point is a good one: If N1a were present somewhere in pre-Neolithic Europe, it would require some kind of "partition" of the pre-Neolithic population, along with its propagation -- presumably southeastward -- into the LBK of central Europe. Seems doubtful.

The study includes an illuminating paragraph about the sources of contaminating sequence in these Neolithic extractions.

Strict precautions were followed during all procedures (including precautions during excavation) and proved to be effective, because all researchers who directly participated in this study (from people working in the field to those working in the laboratory) were genotyped and their sequences were never observed during analyses. However, European sequences were randomly found in clones (28% of the sequences obtained). These specific sequences are regularly observed in the laboratory, whatever the project tackled (including samples from Polynesia or South America), in clones from samples or negative controls. They are not reproducible for a specific sample and are different from researchers' sequences. These facts lead us to suspect the contamination of PCR reagents (Leonard et al., 2007). It was relatively easy, however, to discard those contaminating sequences from our analyses because they were largely in the minority when compared with endogenous sequences.

It would not be very difficult to compare the results from different labs and do a forensic-quality analysis of these reagent contamination events. Surely a good fraction of ancient DNA results prior to the last few years must represent such contamination. Nowadays people have the expectation that Neolithic-era remains may have rare or exotic haplogroups, but it hasn't been so long since people assumed that French equals French. I expressed some concern about this criterion before -- "strange" stands in for "non-contaminated" in too many studies.

It might be very helpful to have a paper outlining the actual contamination pathways that have been found to affect multiple labs. Then the results could be compared against reports that have come out over the years. If people are reluctant to cull doubtful ancient DNA results, at the very least they can target a set for replication studies.

References

Anne-Laure Daniau, Francesco d'Errico and Maria Fernanda Sánchez Goñi went looking for signs that Upper Paleolithic Europeans were using fire to control ecosystems, similar to what is believed to have happened in Southeast Asia, Australia, and the New World under human agency during the terminal Pleistocene.

They didn't find any.

Our results show that contrary to Southeast Asia, no major increase in fire regime is recorded in Southwestern Iberia or in Western France at the onset or after the colonisation of these regions by Modern Human populations. CCsurf values associated in Southeast Asia with Modern Human impact are twice as great as the highest figures recorded in the same sequences for the period before colonisation by Modern Humans. Such a dramatic increase is not observed in our records. Also, no shift is observed in the vegetation apart from that expected by the impact of the millennial scale climatic variability on plant communities, and no increase in taxa that might be related to an increase in fire. Although the Southeast Asian and the European trends are difficult to compare considering the different latitudinal, paleoclimatic and vegetation settings, the coincidence in the former area between the peopling event and the increase in biomass burning makes it conceivable that the two phenomena are related in some way.

Our results strongly argue against the view that Neanderthals and Modern Humans were the driving factor of the large scale variations in fire regime observed in our records, which were clearly governed by the D-O millennial-scale climatic variability and its impact on fuel load. However, we cannot rule out at this stage the possibility that either one or both populations used fire for ecosystem management in ways that did not significantly affect the natural fire trend.

This is a great study. They sure looked hard, sampling microcharcoal particles from a deep sea core covering the span from 70,000 to 10,000 years ago. It's a nice record of fire on the European continent, and shows fluctuations on a millennial timescale. No sign of any other influence -- in particular, no sign that the Upper Paleolithic made any difference at all.

Negative results are in some ways more interesting than positive ones. In this case, it's not so unexpected that the humans didn't burn systematically -- Europe just ain't so easy to burn. Getting some confidence about that gives another kind of climate record. Plus it tells us one thing that didn't hurt the Neandertals.

References:

Daniau A-L, d'Errico F, Sánchez Goñi MF (2010) Testing the Hypothesis of Fire Use for Ecosystem Management by Neanderthal and Upper Palaeolithic Modern Human Populations. PLoS ONE 5(2): e9157. doi:10.1371/journal.pone.0009157

Michael Balter reports on a new radiocarbon calibration called INTCAL09. The calibration curve purports to provide a calendar age calibration up to 50,000 years ago for AMS radiocarbon dates.

Balter's report gives a good account of the basics. The atmospheric concentration of carbon-14 varied over time, so that organisms from some ancient times started with a higher proportion and other times started with a lower proportion. The radiocarbon dating technique depends on knowing this initial carbon-14 proportion. But we can only figure this out by comparing the present carbon-14 proportion in things whose ages we know -- like tree rings. Before 25,000 years ago, good non-radiocarbon chronologies are hard to come by, so up to now there has been no good calibration curve.

More recently, however, thanks to new and more accurate data from foraminifers, corals, and other sources--plus some fancy statistical treatments that help predict which way data gaps bend the curve--the INTCAL group has been able to resolve most of the discrepancies. "It took the group quite a while to come together and agree," says INTCAL team leader Paula Reimer, a geochronologist at Queen's University Belfast in Northern Ireland. But the new data, combined with what Reimer calls a "real sense of necessity" among team members to resolve the debates, won the day.

I'm skeptical when I see calibrated dates because they seldom report the calibration error. I like "fancy statistical treatments" that actually report their error. The entire reason a calibration model like INTCAL09 looks good is that it represents only one component of variability within a large set of separate chronometric datasets. The "debates" are more or less about whether that component is time, and if not what other factors must be controlled. Resolving the debates doesn't mean that the model will reduce the error associated with calibrating a given date -- it (hopefully) means that calibrated dates will be unbiased.

In principle, calibration is good because it facilitates comparison between radiocarbon and other dating methods, like OSL or ESR. It also gives a more accurate view of the temporal scale of events -- the radiocarbon chronology compresses the period between 40,000 and 10,000 years ago into 25,000 radiocarbon years instead of 30,000 calendar years. It makes a difference, if for no other reason, because it makes the initial Upper Paleolithic look more rapid than it really was.

Julien Riel-Salvatore ruminates on similar issues ("Paleolithic radiocarbon legerdemain")

The really bad dating problem happens at points where the atmospheric carbon-14 declined. Some declines occurred with nearly the same rate as actual decay of the carbon-14. A younger sample may then up with the same carbon-14 proportion as an older sample, with no way to tell between them. (I discussed this problem as applied to initial Upper Paleolithic-era dates in "Radiocarbon fudgery".)

Because different datasets vary in their results, apparent declines in atmospheric carbon-14 seem more common in those individual datasets than in the model that reflects their common features. The atmospheric carbon should be better reflected by the model -- after all, there's only one atmosphere, so these datasets should reflect the same value.

But any single series of dates ought to have temporal stochasticity more like an individual dataset. When we take dates from bone collagen -- which is not one of the kinds of data with chronological controls -- there ought to be a separate, source-specific error that we can't control by a calibration model.

Does it matter? I think we should assume the resolution of a 40,000-year-old calibrated radiocarbon date is no better than 3000 years. And in some cases more -- depending on the atmospheric trend. If one date is 3000 years earlier than the other, I think there's a very good likelihood that the earlier date really did happen first.

Too conservative? I'd like to see somebody run the numbers on it.

The paper about the flax fibers found by Eliso Kvavadze and colleagues in Dzudzuana Cave, Republic of Georgia, is a one-pager. The good kind of one-pager -- the kind where you can understand the whole thing. If I didn't hate the misuse of supporting online material so much, I think I might wish that every paper were required to have a one-page synopsis like this. The press accounts about the paper would have been better if they'd just quoted the whole thing!

I find this paper very exciting. Here, in one very clear set of observations, we get a glimpse of a whole human activity pattern. Before this, we knew only hints about fiber processing, later in time and from only one site. Nowadays, most people don't think much about the technology in their T-shirts and jeans. If you're not a fiber artist or knitter, you may not have a concept of just how much work went into clothing and other fiber objects before the Industrial Revolution.

Here, in these little clay samples, is a clear picture of hours upon hours of work. You don't get a variety of color dyes, systematic flax gathering and twisted threads without a sustained tradition. This was technology that contributed directly to survival -- keeping people warm, and helping them fit into their families, clans or tribes. Calories saved by clothing, mats, or padding were calories that did not have to be hunted or gathered. Few technologies could contribute so directly to social status as the kind and quality of clothing. We aren't seeing the beginning of that technology at Dzudzuana, we're seeing it already in a highly developed state.

Flax fibers by themselves would not be newsworthy. Humans gathered plant materials long before 30,000 years ago. Several caves show good evidence of many species of gathered grasses and forbs. We assume that these people, including Neandertals, were using plants as bedding or floor covering materials.

What makes the Dzuzuana fibers different is the evidence that they were incorporated into textiles:

A few of the fibers are colored and appear to have been dyed. A wide range of natural pigments was available to the Upper Paleolithic occupants of the cave, including roots and other plant parts (5). The color range includes yellow, red, blue, violet, black, brown, green, and khaki.

It's like Old Navy! More:

All 27 clay samples from unit D produced fibers of flax (N = 488) (table S2); some were spun (N = 13) and dyed (N = 58), the colors are mostly black-to-gray and turquoise. One of the threads is twisted. The complete fibers are long (>200-m) and composed of segments of smaller lengths. Individual fibers are linear with thin and translucent walls. Several ends of both complete and disbanded fibers were cut across (Fig. 1, 1 to 7).

On the whole, it's very convincing evidence of fabrics. Michael Balter's accompanying news piece was able to dig up some doubters about the extent of dyeing, and maybe a more careful study of the chemical pigments will be possible.

The paper also includes a hint about other fiber processing at the site:

The combination of flax fibers, some tur hair, and microremains of skin beetles (fig. S2) and moth can be interpreted as an evidence for processing of fur, skin, and cloth. This conclusion is supported by the presence of spores of the Chaetomium fungus (fig. S2), usually growing on clothes and other textiles and unfortunately destroying them (6).

How early does it go? Is this a novel invention with the Upper Paleolithic, as has often been suggested of string, nets, and other fiber creations? Were fabrics utilized outside the northern latitudes earlier in time?

Possibly, the fungal evidence might be found at even earlier sites, maybe even by using metagenomic techniques. It's reasonable to think that Neandertals and other early people made extensive use of skin and hair. Woven or knotted fabric is different, but possibly there is a continuum between natural animal fibers and plant fibers that connects them.

References:

Balter M. 2009. Clothes make the (hu)man. Science 325:1329. doi:10.1126/science.325_1329a

Kvavadze E, Bar-Yosef O, Belfer-Cohen A, Boaretto E, Jakeli N, Matskevich Z, Meshviliani T. 2009. 30,000-year-old wild flax fibers. Science 325:1359. doi:10.1126/science.1175404

That image conjured by John Noble Wilford just had me tickled:

It so happens, as Dr. Conard and his co-authors, Susanne C. Münzel of Tubingen and Maria Malina of the Heidelberg Academy of Sciences, noted, the Hohle Fels flute was uncovered in sediments a few feet away from the carved figurine of a busty, nude woman, also around 35,000 years old. The discovery was announced in May by Dr. Conard.

Was this evidence of happy hours after the hunt? Fertility rites or social bonding? The German archaeologists suggested that music in the Stone Age “could have contributed to the maintenance of larger social networks, and thereby perhaps have helped facilitate the demographic and territorial expansion of modern humans.”

The description of the flutes is available in advance copy from Nature. This is one of my pet peeves -- papers in advance of print -- because I can't just enter them into my bibliographic database; there are no volume or page numbers. What a pain.

Mammoth ivory flutes were really hard to make.

The characteristics of these three fragments of ivory are known only from the ivory flute from the upper Aurignacian deposits of Geienklösterle archaeological horizon II (ref. 15). The technology for making an ivory flute is much more complicated than that for making a flute from a bird bone. It requires forming the rough shape along the long axis of a naturally curved piece of mammoth ivory, splitting it open at the interface of the cementum and dentine or along one of the other bedding plains in the ivory, carefully hollowing out the halves, carving the holes and then rejoining the halves of the flute with air-tight seals along the seams that connected the halves of the flute. The ivory flute from Geienklösterle preserves dozens of finely carved notches along the edges of the two halves to facilitate binding and sealing the flute (15). Although thousands of pieces of ivory-working debris and hundreds of ivory artefacts have been recovered from the Aurignacian deposits of Hohle Fels, Vogelherd and Geienklösterle, only the flute fragments have the form described above and preserve a hollowed-out convex morphology, finger holes and series of notches along the edge of the long axis. Thus, we can be confident that these finds represent fragments of ivory flutes similar to the one recovered from Geienklösterle. We recovered the ivory flute from Geienklösterle in 31 small fragments. Given the tendency of delicate ivory artefacts to break into many pieces, it is not unusual to find such pieces in isolation.

The tiny (~1 cm) fragments don't look like much by themselves. Several of them were found only by water screening of sediments. Much more than the "origin of music" angle, I think the attention of Conard's team is the real story here. They had an inkling what to look for, and they started finding the pieces. I wonder how many others may be floating around unrecognized within Upper Paleolithic collections. The thing working against a lot of unrecognized tiny flute fragments is that the Swabian sites seem to have involved dedicated ivory working on a scale that doesn't appear elsewhere.

The flutes made of bird bone are much simpler to manufacture and interpret.

The maker of the flute carved the instrument from the radius of a griffon vulture (Gyps fulvus). This species has a wing span of between 230 and 265 cm and provides bones ideal for large flutes. Griffon vultures and other vultures are documented in the Upper Palaeolithic sediments of the Swabian caves with several examples identified from Gravettian and Aurignacian deposits at Geissenklösterle.

The Geissenklösterle flute has previously been modeled to evaluate its sound characteristics; this has not been done for the new flutes:

The smaller, three-holed bone flute, made from the radius of a swan, that was recovered from the Aurignacian deposits of archaeological horizon II at the nearby cave of Geienklösterle can be played by blowing obliquely into its proximal end to produce four basic notes (10, 11, 12, 13). Three additional overtones can be produced by blowing more sharply into the flute. Given that the three-holed flute from Geienklösterle produces a range of notes comparable to many modern kinds of flute, we expect flute 1 from Hohle Fels to provide a comparable, or perhaps greater, range of notes and musical possibilities (14).

I for one am tired of the boring New-Agey flute music that has been creeping into documentaries about ancient people. So I hope that somebody out there will think a little more broadly about the kind of musical environment these flutes were part of. There would have been a huge potential variety of percussion artifacts. Singing and clapping. Probably not strings, although as long as we're going to talk seriously about arrows in the Upper Paleolithic, a good bowstring has a nice pluck to it.

Now if you're a composer of documentary caveman music, you don't want to take this too far. And by "too far", I mean Ewok celebration from Return of the Jedi "too far." That would not be my idea of a "happy hour." Kapiche?

References:

Conard NJ, Malina M, Münzel SC. 2009. New flutes document the earliest musical tradition in southwestern Germany. Nature (advance online) doi:10.1038/nature08169

I'm a big booster of the idea that human demographic expansion helped drive our recent evolution. So you might expect me to like the new paper by Adam Powell, Stephen Shennan and Mark Thomas, titled, "Late Pleistocene demography and the appearance of modern human behavior." Yet, I see a lot of weaknesses in the paper. I think the paper tries to sidestep several issues about "modern human behavior" that ought to be tackled head-on. In the end, the model in the paper can't describe the data the authors want to consider. Maybe they should have adopted a different model; maybe different data.

I've taken a lot of notes about this -- too many for me to share, but I wanted to review the basic exposition of the paper, including why the authors think demography may determine technological change during the Late Pleistocene. I might post other notes later on the issue of genetic modeling of demography and its relevance for archaeology.

Jennifer Viegas wrote yesterday about excavations at Pavlov VI:

[Jiri] Svoboda, a professor at the University of Brno and director of its Institute of Archaeology, and colleagues recently excavated Pavlov VI, where they found the remains of a female mammoth and one mammoth calf near a 4-foot-wide roasting pit. Arctic fox, wolverine, bear and hare remains were also found, along with a few horse and reindeer bones.

The meats were cooked luau-style underground. Svoboda said, "We found the heating stones still within the pit and around."

The assemblage seems ripe for a museum reconstruction. A few years ago, I heard a number of archaeologists express doubt that megafauna like mammoths and rhinos could have been regularly hunted by Upper Paleolithic people. The phrase "a hunt they would tell their grandchildren about" is one that I remember.

The last few years have brought a lot more hunting-centric perspective. Neandertals hunted rhinoceros at several sites, along with mammoth and sometimes bear. So I suppose when people think about the Upper Paleolithic, they feel like they can step it up a notch.

I pointed a couple of weeks ago to the Les Rois Neandertal paper by Ramirez Rozzi and colleagues.

In the new article section of Journal of Human Evolution, Shara Bailey, Tim Weaver and Jean-Jacques Hublin have a paper that examines the Les Rois sample (among many others) in terms of dental discrete traits. Basically, they set up a discriminant function that can tell Mousterian Neandertals from later Upper Paleolithic people with around 89 percent classification accuracy, and then they applied it to Aurignacian and Châtelperronian dental remains. Here's what they concluded about Les Rois (p. 13):

The analysis of the entire Les Rois sample (n = 15) showed that they have an overwhelmingly ‘modern’ signal. Fourteen of the fifteen individuals had high posterior probabilities of belonging to the Upper Paleolithic modern human group (>80%). This is not unexpected considering the teeth are associated with an Aurignacian industry (Dujardin, 2000) and most come from unit B, which has been dated to 28,715 ± 145 BP using AMS C14. One individual (Mandible B), however, was classified as Neandertal with a low posterior probability (54%) based on 13 traits.

Ramirez Rozzi (pers. comm.) has recently suggested that Mandible B represents a Neandertal, based largely on the asym-
metrical P4 together with some aspects of the corpus. Trinkaus (2007) has also argued that the specimens from Les Rois are mixed in morphology. While the P4 is asymmetrical, a large sagittal crack in the crown exaggerates this feature and the remaining aspects of the tooth are distinctively not Neandertal-like (it lacks a transverse crest and multiple lingual cusps: Fig. 6). In the end, we do not consider the posterior probability of 54% to be compelling enough to conclude, based on dental traits, that there were Neandertals present at Les Rois.

Ramirez Rozzi et al. (2009) made their conclusions about the Les Rois specimens mainly based upon perikymata packing patterns, secondarily supported by tooth sizes and the dental nonmetrics used here. So they are really concluding the same thing about mandible B. What's interesting is that Ramirez Rozzi and colleagues find several other dental individuals from the earlier unit with similar enamel formation patterns, and which they claim are also Neandertals.

In some senses, Les Rois is a good case study for how more complete specimens come to dominate the discussion to the exclusion of other fragmentary remains. Mandible B is itself a tiny piece of a skeleton, but because it has several different anatomical elements on that little piece, the two papers can conduct this kind of in-depth analysis. But the status of the other isolated teeth are equally important -- if Ramirez Rozzi and colleagues are right, they might be enough to establish the earlier Les Rois sample as standing apart from other early Aurignacian-associated samples. If we're talking about a single specimen, however well documented, the situation is somewhat different.

As everybody knows, my null hypothesis is that the samples are mixed in their morphological pattern. On that topic, the more interesting implication of the study by Bailey and colleagues (2009) is that when they applied their discriminant function to Châtelperronian samples, they got a similar classification frequency to Neandertals as for earlier Neandertal samples. And when they applied their function to Aurigacian samples, they got a similar classification frequency to modern humans as for later Upper Paleolithic samples. Under the hypothesis of a mixed transition from earlier Neandertals through later Châtelperronian Neandertals into early Aurignacian and into the Upper Paleolithic, you'd expect the intermediate time steps to give a lower classification frequency -- more Neandertal-like in Aurignacian than later; more modern-like in Châtelperronian than earlier. Bailey and colleagues found that their function classified 85 percent of Aurignacian dental individuals as modern (29/35) compared to 89 percent of later Upper Paleolithic individuals (56/63). Those numbers aren't significantly different, and given the variability in completeness of assigned specimens, I wouldn't go farther.

One possible criticism of the paper is that the morphological pattern that makes up the discriminant mostly consists of traits that are shared by both groups but differ in frequencies. It is still quite possible to use the traits to discriminate individual specimens, but somewhat harder to interpret what a change in trait frequencies means in genetic terms. Bailey and colleagues recognize this issue, and raise it in their discussion of the Oase 2 specimen, for example (p. 12):

Given that the cranium of Oase 2 is clearly not that of a Neandertal (Rougier et al., 2007), the assignment of this individual to the Neandertal group was unexpected. Trinkaus (2007) has suggested that, while essentially ‘modern,’ both Oase 1 and 2 exhibit a mosaic of cranio-dental features, some of which are archaic (e.g., dental proportions, long and flat frontal bone), and others apparently derived towards anatomically modern humans (parietal curvature, absence of supraorbital torus) or towards Neandertals (unilateral lingual bridging of the mandibular canal).

It is important to note that the dental traits aligning Oase 2 with Neandertals are archaic in nature, as they are observed in other fossil hominins as well (Bailey, 2002b, 2006; Martínon-Torres et al., 2007). It is unfortunate that incisor morphology could not be assessed (teeth are missing), and that the upper M1s are too worn to ascertain occlusal polygon shape and occlusal polygon area, since these are features that are likely derived for the Neandertals/Neandertal lineage (Bailey, 2004; Gómez-Robles et al., 2007). Considering that some of the most diagnostic features of the upper dentition could not be assessed and that our approach is not 100% accurate, we caution against over-interpreting the classification of Oase 2.

That's the basic problem of comparing Neandertals with humans, which we encounter genetically as well as morphologically. The groups differ in the frequencies of traits, but not often in the exclusive presence of distinctive ones. Sometimes, what once looked like a distinctive trait is then found in the other group -- so it's not distinctive anymore! Some researchers focus on "distinctive combinations" of traits, which tend to include a mixture of primitive and derived morphologies. But differences in trait frequencies automatically lead to differences in the combination of traits. Sometimes combinations are disproportionately represented (that is, putting traits together separates the samples more than considering them individually), but it is unclear how much of a trait combination may be explained by a history of inbreeding (in isolated populations) and how much may be explained by pleiotropy (of a few genes that differ in frequency).

You'd think this problem would be easier than it is. But look at Les Rois -- a fragmentary but interesting sample, with a blend of morphologies in different specimens. How do we interpret the similarity of Les Rois mandible B to Neandertals? Is it a Neandertal? If we considered the dental nonmetric features alone, as Bailey and colleagues suggest, the specimen looks like a Neandertal but with really rather weak evidence. If we add the perikymata and size data, the similarities with Neandertals are increased, and other teeth from the site also tend to look more Neandertal-like. But we know that perikymata patterns vary in recent human populations. How should we consider this variation as we compare the Les Rois teeth -- should we consider Europeans only, or modern humans more broadly? How did those traits change within the last 30,000 years, and is that relevant to the 10,000 years before?

Well, it's certainly enough to keep things interesting. I'm raising a lot more questions than offering answers. I like the approach Bailey and colleagues have taken because it includes much of the available sample in a way that can be considered as a unit. But then when we return the the issue of particular specimens and the possible patterns of genetic causation of the traits, we are left with the same problems as before.

References:

Bailey SE, Weaver TD, Hublin J-J. 2009. Who made the Aurignacian and other early Upper Paleolithic industries. J Hum Evol (in press) doi:10.1016/j.jhevol.2009.02.003

I don't have much value to add to the "figurative art" angle to the Hohle Fels Venus figurine. It seems very interesting that there is a concentration of carved iconic figures in the Swabian Aurignacian. That has two elements -- first, the concentration itself; second, the focus on carved ivory. Other regional Upper Paleolithic variants have their own concentrations of unique artifacts, sometimes tools (like the Solutrean leaf point) other times found objects (like the fossil shells in the Belgian and German Magdalenian. And we know that other times and places in the Upper Paleolithic have carved objects, so here we have the combination of both, in a very early Upper Paleolithic culture.

I do think it's worth discussing the date of the figurine a little more closely. Conard's paper includes a nice short discussion of the difficulties of establishing an accurate chronology -- a bunch of dates are available spanning much of the sequence, and there is substantial mixing of older and younger dates across the sequence.

There is no simple explanation for the variable radiocarbon dates from Hohle Fels and Geienklösterle. The noisy signals result from a combination of factors including variable sample preparation, variable levels of atmospheric carbon, taphonomic mixing and excavation error. Given the lack of reproducibility within and between radiocarbon laboratories, I prefer to emphasize the stratigraphic context of the finds, and to use the highly variable radiometric dates as rough indicators of age8. Although there is no generally accepted calibration for radiocarbon dates over 30 kyr bp, preliminary calibrations suggest that dates of 32 kyr bp correspond to roughly 36 kyr bp in calendar years. If the early dates are correct, the Venus would be even older. The fact that the Venus is overlain by five Aurignacian horizons, containing a dozen stratigraphically intact anthropogenic features with a total thickness of 1 m, suggests that the figurine is of an age corresponding to the start of the Aurignacian, around 40,000 calendar years ago.

The paper also includes a very nice picture showing the stratigraphy profile of the site in terms of artifact positions, color-coded by level. The Venus does lie beneath a well-stratified Aurignacian, with a depth of in this area of more than a half meter, although I am also impressed by the overlying meter of "Gravettian-Aurignacian transition." Conard's text is slightly more definitive than the figure, since two of the five "overlying" Aurignacian layers are not represented directly above the artifact, and one appears mostly to underlie it.

The research report is accompanied by a perspective piece by Paul Mellars. He frames the importance of the site by referring to its early date:

Fragments of the figure were excavated from archaeological deposits in the Hohle Fels cave in south Germany, dated by a range of more than 30 radiocarbon measurements to at least 35,000 years in age (in terms of the newly 'calibrated' radiocarbon timescale) (Mellars 2009:176).

This is a tricky statement to parse. Conard provides eight radiocarbon dates for objects in the lowest Aurignacian level (Vb) at Hohle Fels, only two of these are older than 35,000 radiocarbon years. Mellars refers to calibrated dates, not radiocarbon dates. On that basis, the statement is likely correct but a little misleading in comparison with later, Gravettian-associated figurines, whose dates are reported in uncalibrated years.

For those not familiar with the arcana of radiocarbon dating, the atmospheric proportion of carbon-14 varied during the last 40,000 years, so that there was actually more or less of it at some times than others. For the oldest radiocarbon dates, up above 25,000 BP, the age reported in half-lifes is systematically younger than the real age of an object in calendar years (given in "years ago" or some such). Over the span above 30,000 years ago, the difference is up to 5000 years or more -- so that a radiocarbon date of 30,000 BP might correspond to a calendar date older than 35,000 years ago.

This creates the potential for much confusion when describing dates. In this case, what does it mean to see that a Venus figurine from the Aurignacian is "more than 35,000 years old" when other figurines from the Gravettian date to "25,000 BP"? There's a 5000-year gap between those two timescales -- one that amounts to a sixth of the total age of an artifact. And when we read that an object is "more than 35,000 years old" and remember that Neandertals lived up to "29,000 BP" it is very easy to forget that these dates may well be synchronous. So we have to continually remind ourselves to use comparable timescales when talking about objects in the Upper Paleolithic.

I've discussed the problems with radiocarbon calibration at some length, in association with some earlier work by Mellars. Sometimes I find that reading and learning more about a subject actually clarifies matters a bit. In the case of radiocarbon chronology, it seems that the more I learn, the more confused things really are.

Given the error associated with calibration and atmospheric variation, it is no surprise (as Conard reports in the paper) that the radiocarbon dates in a site over around 30,000 BP should be somewhat mixed and confused. The problem is not so much that ten objects from the same moment will have different proportions of carbon-14, it is that ten objects from different times may have the same proportion. So it is especially important to understand the stratigraphy of a site completely. This appears to be a good, conservative example, and it will be interesting to see what happens if the excavation progresses further into the deeper underlying Mousterian.

But meanwhile there are other sites, excavated in a range of circumstances, in which the stratigraphy was not so carefully documented, or may have been more mixed. I suspect we'll be hearing more confusion before we get a lot more clarification.

References:

Mellars P. 2009. Origins of the female image. Nature 459:176-177. doi:10.1038/459176a

Conard NJ. 2009. A female figurine from the basal Aurignacian of Hohle Fels Cave in southwestern Germany. Nature 459:248-252. doi:10.1038/nature07995

I said I was going to do my best to scoop the press this week. How about this piece of undernews: at one of the few early Aurignacian sites to preserve skeletal remains, Les Rois, France, one of the Aurignacian-associated mandibles looks like it may have been a Neandertal.

Before I tell the whole story, let me telegraph the bottom line: Do I think this specimen was really an Aurignacian Neandertal?

My opinion has always been that Europeans in the time span from 40,000 to 25,000 radiocarbon years presented a varying mixture of "Neandertal" and "modern" morphological features. From that standpoint, it is not surprising to find a mandible that has the combination of features reported here. In this case, the most significant mandible (which is really quite a small fragment) shows one very interesting characteristic: a perikymata count and packing pattern similar to Neandertals and different from other Upper Paleolithic European teeth. But as I'll point out below, living humans are variable in their enamel formation in ways that reduce the significance of the differences between Neandertals and later Europeans.

But the story is significant -- not only do these remains extend the biological variability of known Aurignacian-associated people to include Neandertal-like developmental patterns, but also they help to inform us about the potential of cultural associations at other sites, including Vindija.

I just read the new paper by Philipp Gunz and colleagues, titled, "Early modern human diversity suggests subdivided population structure and a complex out-of-Africa scenario". That's a mouthful.

The late Middle Pleistocene population of Africa was genetically variable, and that genetic variability is probably the biggest component of genetic variation still remaining in living humans. Moreover, the phenotypic variability of the Levantine sample has been recognized since its initial description by McCown and Keith (1939). So to read this is not surprising:

Seemingly ancient contributions to the modern human gene pool (36) have been explained by admixture with archaic forms of Homo, e.g., Neanderthals. Although we cannot rule out such admixture (37), the clear morphological distinction between AMH and archaic forms of Homo in the light of the proposed ancestral population structure of early AMH to us suggests another underestimated possibility: the genetic exchange between subdivided populations of early AMH as a potential source for ‘‘ancient’’ contributions to the modern human gene pool (9, 36).

I've stressed the importance of African population structure before (e.g., Hawks et al. 2008). So I agree completely with this part of the interpretation in the paper: African variation was larger than in other regions, and it was important.

But that being said, these morphometric comparisons are not very straightforward. Some comments:

1. Phenotypic variance is not a measure of genetic variance. If we see a population that has a large measure of phenotypic variability, it does not mean that the population had much genetic variability. Perversely, genetic variability can sometimes be lower in a population that has greater phenotypic variance -- often because genetic drift can cause a loss of epistases that once constrained the phenotype. In some cases environmental variance may actually increase when the additive genetic variance declines, because of a loss of developmental robusticity. In any event, we can't just go from a variable phenotype and infer that there's variation in genotypes.

2. There's no evidence for subdivision here. They measure a high phenotypic variance within the sample they refer to early modern humans. But that variance is expressed not mainly between geographic locations in the sample, but within them. Qafzeh 6 and 9 are far apart; Jebel Irhoud 2 and Skhul 5 are close together. The East African fossils Omo 2 and LH 18 are far apart. This isn't subdivision, it's just high within-population variance.

3. Weird sample composition. The early modern human sample includes the African and Levantine crania complete enough for analysis. But why lump these? Why is the South African Fish Hoek skull lumped with Upper Paleolithic Europeans?

4. Temporal range. There are two samples here that have a high average distance between nearest neighbors in the sample: "archaic" humans and early modern ones. What these two samples have in common is that they each cover a much larger range of time than the other samples. The early modern sample spans more than 100,000 years by current dates. That's more 80,000 years longer than the Upper Paleolithic sample, 50,000 years longer than the Neandertal sample -- a huge component of variance that is uncontrolled in the other samples.

5. Principal components. PC axes are those that account for the largest covariances in the sample. If two samples are lumped together, there is a within-population component of variance and a between-population component. These may be partly independent in their effects on the total variance, or they may not be. In any event, if we derive the PC structure from the total sample, or even from the individual samples pooled together, the larger samples will weight the PC structure more toward the factors that explain their within-sample covariances. In this case, we have many more recent humans than fossil ones, and many more archaic humans and Neandertals than "early modern" humans. It's hard to have an intuitive idea about the biases that can result from sample composition, and that's a big reason for caution.

Those are all reasons for re-examining the results in different ways. In particular, if I were doing this kind of analysis, I would repeat it for subsets of the cranium, where I could include a larger number of fragmentary fossils. If the African-Levantine sample is really unusually variable, that should hold up strongly when we examine parts as well as the whole cranium.

Well, although I listed several reasons for caution, we can ask how to interpret the study's conclusion:

Any model consistent with our data requires a more dynamic scenario and a more complex population structure than the one implied by the classic Out-of-Africa model.

If we take the high variance of their "early modern" sample at face value, what we have to conclude is that later humans evolved substantially less phenotypic variance than African-West Asian people who lived between 200,000 and 90,000 years ago. Genetics tells us that there was no massive genetic drift during the time span after 90,000 years ago within Africa. Thus we must conclude that some other force resulted in a significant restriction of the phenotypic variation of recent humans, including people who lived as long as 40,000 years ago.

My hypothesis would be natural selection on some significant subset of phenotypic characters, which reduced the phenotypic variance of most of the cranium by pleiotropy. An out-of-Africa migration is not sufficient to explain the reduction in variance, because all modern humans are limited in phenotypic variance, not only non-Africans. Selection on some significant set of genes would help to explain why the ancestral African population predominated within the last 100,000 years. This selection would have predated most of the recent acceleration we observe in the genomic variation of current populations -- indeed, whatever set of genes was strongly selected before 50,000 years ago might have been fixed long ago.

A wave of selection can promote dispersal and demographic growth without the necessity of complete population replacement (cf. Eswaran 2002). A substantial transition in the genetic background would alter the phenotypic effects of any genes that remained in non-Africans from their local ancestors. In other words, the answer about what happened to fossil humans outside of Africa depends on the kind of events that happened inside Africa. So from that perspective, this research is very interesting.

References:

Gunz P, Bookstein FL, Mitteroecker P, Stadlmayr A, Seidler H, Weber GW. 2009. Early modern human diversity suggests subdivided population structure and a complex out-of-Africa scenario. Proc Nat Acad Sci USA (early online) doi:10.1073/pnas.0909160106

Eswaran V. 2002. A diffusion wave out of Africa: the mechanism of the modern human revolution? Curr Anthropol 43:749-774.

McCown TD, Keith A. 1939. The Stone Age Man of Mount Carmel: The fossil human remains from the Levalloiso-Mousterian. Clarendon Press, Oxford.

The local paper gives us a snippet of news about ongoing work at Kent's Cavern:

AN ULTRA modern search at Kents Cavern hopes to uncover clues missed by the Victorians.

Two archaeologists are planning to excavate a small part of Kents Cavern, Torquay, to unravel their quest to see if modern man lived alongside Neanderthals.

...

The dig is being carried out by archaeologists Dr Mark White, of Durham University, and Dr Paul Pettitt, of Sheffield University.

They plan to use modern techniques of almost 150 years of improvements in archaeology to determine what conditions existed in the cave tens of thousand of years ago.

They will be using 3D mapping, microscopes, and chemical analysis, as well as traditional methods of brush and trowel, to work out how sediments were deposited in the cave entrance, and what vegetable and animal remains are buried.

More at the link, including some about the cave's history. I wrote about Kent's Cavern in 2005, and again in late 2006, when the rumor was a claim that the Upper Paleolithic maxilla might date to as early as 37,000 years ago. No word since then.

Dr Pettitt said: "We aim to link Neanderthal extinction with the spread of modern man into Britain.

They're certainly following up on the idea that Kent's Cavern is the early significant UP site in Britain.

I've been out of e-mail range for the past week. In the meantime several people e-mailed me this new paper:

Neanderthal Extinction by Competitive Exclusion

Background: Despite a long history of investigation, considerable debate revolves around whether Neanderthals became extinct because of climate change or competition with anatomically modern humans (AMH).

Methodology/Principal Findings: We apply a new methodology integrating archaeological and chronological data with high-resolution paleoclimatic simulations to define eco-cultural niches associated with Neanderthal and AMH adaptive systems during alternating cold and mild phases of Marine Isotope Stage 3. Our results indicate that Neanderthals and AMH exploited similar niches, and may have continued to do so in the absence of contact.

Conclusions/Significance: The southerly contraction of Neanderthal range in southwestern Europe during Greenland Interstadial 8 was not due to climate change or a change in adaptation, but rather concurrent AMH geographic expansion appears to have produced competition that led to Neanderthal extinction.

OK, so should we believe it?

The authors are out to test the idea that climate killed the Neandertals (also covered by me in 2007, not to mention "The unbearable hotness" from last week).

The authors confine their analysis to a simple question: Were the European ecologies of the later times of Neandertal existence compatible with those that existed slightly earlier? If the climate deterioration is insufficient to explain the range reduction of late Neandertal sites, then we need some other factor. Competition with the non-Neandertal population would be a logical hypothesis, in this event.

Competitive exclusion is not a new concept applied to Neandertals. The novel element in the paper is its inclusion of paleoclimate models to support the hypothesis that Neandertals and modern humans actually would have competed in the same niche.

The authors applied an optimization algorithm to data. The data included:

1. Paleoclimate predictions for small areal units within Europe for three time periods between 43,000 and 35,000 (calibrated) years ago.

2. The locations and dates of archaeological sites dating to these periods, whether Mousterian, Châtelperronian, or Aurignacian. The first two are assumed Neandertal, the third modern human.

The algorithm tries to find shared paleoclimate features among the locations represented by archaeological sites. Once these are found, the algorithm finds other areas that fit the same paleoclimate parameters as those where archaeological sites were found. In other words, it is an attempt to determine the total ecological range of the populations represented by the sites.

For example, here are the results for the earliest of the three time periods, H4. This is a comparison of the maps of Europe for both the Mousterian-Châtelperronian (left) and Aurignacian (right) archaeological samples:

In this map, red areas are those predicted to be suitable for habitation by Mousterian-Châtelperronian (left) and Aurigacian (right) populations, respectively. One thing stands out: they have almost identical ecological tolerances. Modern humans were not using different ecological zones than Neandertals. The analysis of the later periods shows that the modern humans were not exploiting climate changes at the expense of Neandertals.

The key graph of the paper shows that during the latest time period, near 35,000 years ago, the paleoclimate models predict a very large area of Europe would have been suitable for Neandertal habitation -- at least, if their habitation were constrained only by climate. But the Neandertal sites during that time period are restricted to a very small area. So some additional factor is required. The authors promote the hypothesis that the important factor was the population growth of modern humans.

Now, should we doubt the results? I think this is a good test of the hypothesis that climate change killed the Neandertals. It didn't. They survived through an entire glacial cycle before 40,000 years ago. Without some other factor, they would still be here today.

The paper is stronger than many that have tried to make a similar argument -- that climate couldn't have killed various extinct megafauna. In large part, that is because both the American megafaunal disappearances and the entry and growth of human populations coincided with a period of rapid climate change. In the time frame of the last Neandertals, there were important climate changes, but the paleoclimate models indicate that these changes weren't enough to make Europe uninhabitable for either humans or Neandertals.

The paper is not a test of Neandertal genetic extinction. It takes Neandertal population disappearance as a given. Models that involve gene flow or cultural exchanges between Neandertals and other populations are not part of this paper's scheme.

In this sense, the assumption that the archaeological industries can be analyzed with methods developed for species seems questionable. The paper acknowledges this issue:

Our assumption is that human adaptive systems, defined here as the range of technological and settlement systems shared and transmitted by a culturally cohesive population within a specific paleoenvironmental framework, can be considered to operate as a ‘species’ with respect to their interaction with the environment. This does not imply, however, that human adaptive systems necessarily remained stable over time, as might be the case with animal species occupying narrow and stable niches. Humans can change their adaptive systems rapidly through technical and social innovations in response to environmental change. We know, however, that this was not the case during the late Middle and Upper Paleolithic, periods during which specific human adaptive systems spanned a number of climatic events. Thus, the method described in this study is particularly relevant for addressing issues of human adaptive system stability and eco-cultural niche stability (Banks et al. 2008:2).

But Neandertals during the span from 43,000 to 35,000 years ago were adopting various Upper Paleolithic technological elements. That seems to contradict the assumption that the "technological and settlement systems...operate as a 'species'." Instead, it seems to indicate that these systems changed significantly across the time frame modeled in the paper. I don't think that observation weakens the hypothesis that modern and Neandertal populations may have competed in the same ecological niche. If the Neandertals were using the same technical elements, it probably reinforces the hypothesis of competition.

But I think it is important to bear in mind what the paper tested. The analysis rejects the hypothesis that climate was sufficient to drive a range restriction of Mousterian and Châtelperronian. It doesn't provide additional information about the mode of such restrictions. With that in mind, I admire the paper and see some useful additional work that might be tackled with similar methods.

References:

Banks WE, d’Errico F, Peterson AT, Kageyama M, Sima A, et al. (2008) Neanderthal Extinction by Competitive Exclusion. PLoS ONE 3(12): e3972. doi:10.1371/journal.pone.0003972

Few details, as work is just underway. No dates. This is from a story in the Independent (UK):

Workers constructing a sewage line through a forest in northern Israel stumbled across a large cave containing stalactites and strewn with discarded fragments of prehistoric tools and the burnt bones of animals which have long been extinct in the region, including red deer, fallow deer, buffalo and even bears.

The article refers to a "number of chambers, the main one measuring 60 m by 80 m."

If you have a subscription to Nature, you can get a short story from last week's issue, which explores the reaction of a couple of genetics-types to finding Neandertal genes responsible for human mental abilities:

That has to be interbreeding. The earlier studies had missed it because they hadn't considered the changing impact of natural selection over time."

"You can back that up?"

"Absolutely." Beth was always meticulous about her data.

I didn't have to force a smile. "That's fascinating," I said. "It will make Nature for sure." It would get a lot of people hot under their collective collars, but that was fine. Evidence of interbreeding with Neanderthals would create a new paradigm for hybridization being behind the rapid advance of modern humans and make me famous. "What genes are involved?"

Notice: you can tell this is fiction because the result "will make Nature for sure"!

On the other hand, some parts are uncomfortably true-to-life:

"I'm a scientist. I want to know the truth!" More importantly, I wanted to finish the contract; that was my job as principal investigator. I'd always succeeded before; that was why after two decades at the university I was department chair and Beth was still a research assistant.

Yes, the plucky female scientist who believes in the Neandertals is passed over for advancement, while the overbearing man who cares only about grant applications runs the whole department. Well, try to tell me that part is fictional!

It's not that great a story, but the surprise conclusion is exactly what we've been writing -- some aspects of today's human brain biology probably reflect the genetic interactions between Pleistocene human populations. It's neither shocking nor surprising. It's simply evolution!

References:

Hecht J. 2008. The Neanderthal correlation. Nature 453:562. doi:10.1038/453562a

Science's Michael Balter reviews the recent Cambridge conference on "Global Origins and Development of Seafaring". The article begins with a suggestion that the first inhabitants of Flores floated there on vegetation rafts by accident -- channel crossings being otherwise impossible for Lower Paleolithic hominids:

"Flores is the exception that proves the rule in terms of when seafaring really began," says Atholl Anderson, a prehistorian at the Australian National University (ANU) in Canberra. [Jon] Erlandson agrees: "Otherwise, H. erectus should have colonized Australia and the surrounding islands."

It mostly seems to be about Wallacea, Sahul, and Melanesia.

The article features a disagreement concerning the colonization of these regions. Some think that island colonizations started before seafaring technology was quite ready for prime time. In that scenario, the initial habitation of parts of Wallacea along with Australia and New Guinea was a sort of accidental chain of small founding events, possibly as early as 60,000 years ago or earlier.

The opposing viewpoint holds that these islands (and continent) were inhabited relatively late and quite suddenly, by people who had developed an advanced seafaring skill. Balter quotes University of Utah archaeologist Jim O'Connell to good effect:

In the last few years, O'Connell, together with archaeologist Jim Allen of La Trobe University in Bundoora, Australia, has argued from a detailed analysis of radiocarbon dates for a "short chronology" that puts the occupation of Sahul no earlier than about 50,000 years ago. He pointed out that by 45,000 years ago modern humans had colonized a number of islands between Sunda and Sahul, called the Wallacean Archipelago, which stretched at least 1000 kilometers even when sea levels were at their lowest. Reaching many of these islands required sea crossings of 30 to 70 kilometers, sometimes against the currents. Most animals from Asia never achieved these crossings, implying that humans must have used technology to do it. That 5000 years of colonization, O'Connell said, represented a relatively short "archaeological instant."

O'Connell also argues that some of the island sites before 40,000 years ago include deep-water fish, suggesting relatively advanced ocean-going boats at that time -- something I noted in a post on the East Timor site, Jerimalai.

Which side is right? I don't know, but it's good that they are formulating hypotheses this way, involving the technological trajectory, genetic constraints on small populations, and various ecological parameters.

References:

Balter M. 2007. In search of the world's most ancient mariners. Science 318:388-389. doi:10.1126/science.318.5849.388

Der Spiegel reports on recent portable art finds at Vogelherd, Germany:

The figure of the woolly mammoth is tiny, measuring just 3.7 cm long and weighing a mere 7.5 grams, and displays skilfully detailed carvings. It is unique in its slim form, pointed tail, powerful legs and dynamically arched trunk. It is decorated with six short incisions, and the soles of the pachyderm's feet show a crosshatch pattern. The miniature lion is 5.6 cm long, has a extended torso and outstretched neck. It is decorated with approximately 30 finely incised crosses on its spine.

Nick Conard at Tübingen is quoted; he's the responsible archaeologist. The story is on occasion of the mammoth and other artifacts going on display at a museum exhibit. They are dated Aurignacian, which makes them among the earliest examples of figurative art in Europe.

It's likely that these include the figurines that Conard was presenting in 2003, as reported by Rex Dalton, although a mammoth was not mentioned at the time. A series of portable art figures were discovered at Vogelherd by Gustav Riek, who excavated the cave in 1931. Several of these are housed at the Museum Schloss Hohentübingen, including another mammoth. Conard (2003), in his description of portable art from Hohle Fels, includes a table listing 10 figurines from Vogelherd, all found in the original excavation by Riek.

Conard and colleagues (2003) reported on the radiocarbon chronology of the Aurignacian at Vogelherd, finding a range of AMS dates between around 29,000 and 36,000 radiocarbon years, with most dates clustering between 30,000 and 31,000. Figurines from other caves in the region date to the same age range, including those from Hohle Fels, Geissenklüsterle, and the Löwenmensch, or "Lion-man" from Hohlenstein-Stadel. This area preserves an exceptional sample of early Aurignacian art objects.

References:

Conard NJ. 2003. Palaeolithic ivory sculptures from southwestern Germany and the origins of figurative art. Nature 426:830-832. doi:10.1038/nature02186

James Adovasio, Olga Soffer and Jake Page have a new book entitled, The Invisible Sex: Uncovering the True Roles of Women in Prehistory. The authors are well-known for their work in both New World and Old World archaeology. In particular, the joint work by Adovasio and Soffer has uncovered evidence for the earliest fabrics and fiber technology, and has led to new interpretations for the famous "Venus" figurines from the European Upper Paleolithic.

I ran across a nice long review of the book by Laura Miller at Salon.com. It's free if you watch their ads, and the review is full of clever observations. Here's a sample:

Their point is that, like Hollywood action films, many early conceptions of prehistoric life were fantasies, the work of anthropologists caught up in a thrillingly macho vision of our forebears that owes more to Conan the Barbarian than to the archaeological record. That vision rarely featured women, and when they did appear it was only to sit around awaiting the next delivery of mammoth steaks, for which, it was implied, they would trade their sexual favors or perhaps the handful of nuts and berries they'd rustled up on the side. So seductive is this "theme of man the hunter" that it prevailed when the remains of a diminutive new species of the genus Homo were discovered on the Indonesian island of Flores in 2004 (and promptly labeled "hobbits" by the press). An artist's drawing of the creature depicted it as bearded fellow holding a spear and carrying a freshly slain giant rat slung over his shoulder -- despite the fact that the chief find was a female.

The review notes that the book also covers the anatomical constraints of the birth process in humans and their implications for cultural assistance with birth -- that's drawn from work by Karen Rosenberg and Wenda Trevathan (quick summary here) -- and I happened to have lectured about it today. It's very important stuff in terms of human life history strategies, and it is likely tied in with the evolution of the human brain. So anatomically speaking, women are central!

I hope to write more about this book when I get a chance to read it -- Soffer and Adovasio have been really important in reframing our understanding of sex roles in the past, and this looks like an interesting contribution.