The questionable contribution of the Neolithic and the Bronze Age to European craniofacial form (?)

C. Loring Brace and colleagues have published a new paper in PNAS which examines several populations from West Eurasia and Africa based on 24 cranial measurements.

The first canonical variate (horizontal) clearly separates the Niger-Congo group from the other populations:



According to Brace et al:

When the samples used in Fig. 1 are compared by the use of canonical variate plots as in Fig. 2, the separateness of the Niger-Congo speakers is again quite clear. Interestingly enough, however, the small Natufian sample falls between the Niger-Congo group and the other samples used. Fig. 2 shows the plot produced by the first two canonical variates, but the same thing happens when canonical variates 1 and 3 (not shown here) are used. This placement suggests that there may have been a Sub-Saharan African element in the make-up of the Natufians (the putative ancestors of the subsequent Neolithic), although in this particular test there is no such evident presence in the North African or Egyptian samples. As shown in Fig. 1, the Somalis and the Egyptian Bronze Age sample from Naqada may also have a hint of a Sub-Saharan African component. That was not borne out in the canonical variate plot (Fig. 2), and there was no evidence of such an involvement in the Algerian Neolithic (Gambetta) sample.

Brace et al. also combined samples into regional groups. The canonical variate plot again shows the separate of the Niger-Congo group, and the intermediacy of the Natufians between West Eurasians and North/East Africans and Eurasians.



The raw Mahalanobis distances are quite informative.



It can be easily seen that the Niger-Congo have high distances from all other populations, except Northeast Africans. Northeast Africans are however closer to Late Prehistoric Eurasians and Modern Europeans than to the Niger-Congo group. This, once more, establishes the intermediacy of Northeast Africans between Caucasoids and Sub-Saharan Africans.

All populations except the Niger-Congo and the Natufians are close to each other. The Natufians have very high distances from other samples. Their closest neighbors are first, Late Prehistoric Eurasia, and second, Niger-Congo.

According to Brace:

The generally high D2 values for the Natufian sample in Table 3 are almost certainly a reflection of the very small sample size.

The Natufian sample consisted of only 4 individuals. Thus, it appears that the high distances of the Niger-Congo group are indicative of its biological distinctiveness, whereas the high distances of the Natufians are due to the small sample size.

Brace's conclusion is stated in conditional form:

If the Late Pleistocene Natufian sample from Israel is the source from which that Neolithic spread was derived, then there was clearly a Sub-Saharan African element present of almost equal importance as the Late Prehistoric Eurasian element. At the same time, the failure of the Neolithic and Bronze Age samples in central and northern Europe to tie to the modern inhabitants supports the suggestion that, while a farming mode of subsistence was spread westward and also north to Crimea and east to Mongolia by actual movement of communities of farmers, the indigenous foragers in each of those areas ultimately absorbed both the agricultural subsistence strategy and also the people who had brought it.

The "if" portion of the statement is problematic. While Natufians are widely acknowledged as a culture anticipating the arrival of the Neolithic, they were not the first Neolithic agriculturalists, nor where they the immediate source of the transmission of agriculture. According to Pinhasi and Pluciennik (CURRENT ANTHROPOLOGY Volume 45, Number S4, August-October 2004):

Analysis of the material suggests that there was considerable morphological heterogeneity among the earliest farmers of the Levant belonging to the Pre-Pottery Neolithic but that similar variability is generally not seen among the earliest mainland agriculturalists of south-eastern Europe. We propose that this may be explained by the existence of a genetic "bottleneck" among Anatolian populations and that it supports models of the largely exogenous origin of many early Neolithic populations in this region.

Thus, the sample of 4 Natufian individuals does not represent the first pre-pottery Neolithic populations, and moreover, it does not represent the immediate source of the Neolithic in Europe, which was that of the Neolithic agriculturalists of Anatolia. As Pinhasi and Pluciennik state:

Analysis of morphological variability in the Near East and Europe (here and in Pinhasi 2003) suggests that the Epipalaeolithic populations from the Natufian Levant were noticeably different to the Mesolithic populations described from the Danube Gorge, the western Mediterranean, and central Europe. No close similarities were observed between Early Neolithic and Mesolithic European groups in any of the regions studied, with the possible exception of Mediterranean Europe. However, neither were clear affinities observed between Epipalaeolithic Near Eastern groups and any other Neolithic or Mesolithic groups.

The last statement is important, because it establishes that the Natufians did not have clear associations with the first Neolithic groups. So, while they are believed to be pre-agricultural culturally they are not related to any Neolithic groups biologically.

Brace finds similarities between the ancient Neolithic culture-bearers and modern Mediterranean populations, which is no doubt accurate. On the other hand, in continental Europe, the "signal" of the Neolithic populations has been absorbed by the indigenous inhabitants. This is all fine, and agrees nicely with the picture presented sixty five years ago by Carleton Coon, whereby the invasion of Europe by gracile dolichomorphs (skeletally Mediterranean) populations was followed by a period of absorption and "re-emergence" of the Upper Paleolithic types and their mixtures with the Mediterraneans.

Indeed, the early inhabitants of Northern Europe were robust broad-faced Cro-Magnoids, unlike the gracile narrow-faced Mediterraneans which diffused through Central Europe from a proximate Southeastern European source. Brace studies Cro-Magnon to propose that:

If this analysis shows nothing else, it demonstrates that the oft-repeated European feeling that the Cro-Magnons are ‘‘us’’ (47) is more a product of anthropological folklore than the result of the metric data available from the skeletal remains.

Yes, this bizarre statement is not supported by his own data, which shows that Cro-Magnon shows that the Modern European sample is the only one to which Cro-Magnon is aligned to, however distantly:



The retention of the "Upper Paleolithic" signal in modern Europeans is quite impressive, since Europe's colonization did not cease with Cro-Magnon in the first Upper Paleolithic.

Cro-Magnon was a coarse-featured and robust skull atypical of modern Europeans, but one may still find individuals in Europe which resemble him: Brace et al. did not test for his resemblance to individuals. Moreover, he did not test Cro-Magnon against individual European populations. For example, Jantz and Owsley concluded that:

Using raw measurements, 6 of 8 express an affinity to Norse, and with the shape variables of Darroch and Mosimann ([1985]), 5 of 8 express a similarity to Norse. Using shape variables reduces the Mahalanobis distance, substantially in some cases. Typicality probabilities (Wilson, [1981]), particularly for the shape variables, show the crania to be fairly typical of recent populations. The results presented in Table 1 are consistent with the idea that Upper Paleolithic crania are, for the most part, larger and more generalized versions of recent Europeans. Howells ([1995]) reached a similar conclusion with respect to European Mesolithic crania.

UPDATE

I have sent the following questions to Dr. Brace regarding his study. If and when he responds, and if I am granted permission to publish his response, I will do so in these entry:

You state that Modern Europeans are not very closely linked to
Neolithic/Bronze Age Europeans, yet in Table 3, the distance between
"Modern Europe" and "Late Prehistoric Eurasia" is 1.87 which is the
lowest among all population pairs. "Late Prehistoric Eurasia" is
defined as:

"Then Neolithic samples from Denmark, England, France, Germany, and
Portugal were combined with Bronze Age samples from England, Jericho,
and Mongolia to make a ''Late Prehistoric Eurasia'' sample."

This would seem to indicate a strong affinity between Neolithic/Bronze
Age Europeans and modern Europeans.

Moreover, you state that "the oft-repeated European feeling that the
Cro-Magnons are ''us'' (47) is more a product of anthropological
folklore than the result of the metric data available from the
skeletal remains."

But, in Table 4, Cro-Magnon I shows mixed affiliations between Modern
Europe and Late Prehistoric Eurasia. The inability to fall completely
in either Modern Europe or LP Eurasia is not surprising, since Modern
Europe and Late Prehistoric Eurasia are extremely close to each other
(Table 3). So, the data in Table 4 seem to suggest that Cro-Magnon I
did in fact resemble modern Europeans and Late Prehistoric Eurasians.

I would be very interested in hearing your comments.

Proc. Natl. Acad. Sci. USA, 10.1073/pnas.0509801102

The questionable contribution of the Neolithic and the Bronze Age to European craniofacial form

C. Loring Brace et al.

Many human craniofacial dimensions are largely of neutral adaptive significance, and an analysis of their variation can serve as an indication of the extent to which any given population is genetically related to or differs from any other. When 24 craniofacial measurements of a series of human populations are used to generate neighbor-joining dendrograms, it is no surprise that all modern European groups, ranging all of the way from Scandinavia to eastern Europe and throughout the Mediterranean to the Middle East, show that they are closely related to each other. The surprise is that the Neolithic peoples of Europe and their Bronze Age successors are not closely related to the modern inhabitants, although the prehistoric/modern ties are somewhat more apparent in southern Europe. It is a further surprise that the Epipalaeolithic Natufian of Israel from whom the Neolithic realm was assumed to arise has a clear link to Sub-Saharan Africa. Basques and Canary Islanders are clearly associated with modern Europeans. When canonical variates are plotted, neither sample ties in with Cro-Magnon as was once suggested. The data treated here support the idea that the Neolithic moved out of the Near East into the circum-Mediterranean areas and Europe by a process of demic diffusion but that subsequently the in situ residents of those areas, derived from the Late Pleistocene inhabitants, absorbed both the agricultural life way and the people who had brought it.

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