China: an intermediate position

either evolved very recently or that the immediate Pleistocene ancestors of most East Asian peoples remain to be identified in the fossil record.

Africans exhibit a number of East Asian features which are shared with Indonesians, Australo-Melanesians, and Polynesians. On the other side, the Inuit show a number of East Asian features, some of them with high frequencies or pronounced expression, even compared to the Chinese.

Similar results were obtained by Lahr (1994, 1996) who examined eleven East Asian regional continuity traits: sagittal keeling, mandibular exostoses, horizontal course of naso-frontal and fronto-maxillary sutures, profile of nasal saddle and nasal roof, rounded frontals, orbital shape, M3 agenesis, reduced posterior dentition, facial flatness (prognathism), lateral facial flatness and rounding of the infero-lateral margin of the orbit.

Lahr found that sagittal keeling did not only occur in the Chinese but also in the Australian population. For the course of the nasofrontal and frontomaxillary sutures, the Chinese even exhibited a curved condition for both sutures. The variation in profile of the nasal saddle and nasal roof is great among the Chinese, in which flat nasals occur in only 26.8%, whereas they occur more frequently in sub-Saharan Africans (34%). The orbital shape also varies strongly, so that no particular shape appears to consistently characterize the East Asians. Another trait - the lack of facial prognathism - was most pronounced among Europeans.

The answer to the question at the beginning of this section concerning the interregional affinities and differences is that the morphological basis does not support the hypothesis of regional continuity. The features occur widely in different regions.

5.1.2.1 Chinese Pleistocene population

With respect to the Chinese fossils, it has been shown in the previous section that no indication of homogeneity has been found. The Principal Components Analyses show that the fossil hominids are widely scattered with regard to the recent centroids. Actually, Weidenreich (1943) had already detected this phenomenon. Weidenreich saw that Upper Cave 102 and 103 resemble Australoid and Eskimoid, respectively. Only Upper Cave 101 was regarded to be affiliated with the recent Chinese and was believed to be a direct ancestor of modern Chinese. This view has been strongly criticized by Wu (1995; see also Wolpoff et al., 1984). Wu stated that all Zhoukoudian Upper Cave crania show affinities with recent Chinese. The facts that were seen by Weidenreich based on his observations on the Zhoukoudian Lower and Upper Cave crania and the results of this study support the view that during the Middle and Late Pleistocene there was a great variability in the ancient Chinese population. As mentioned above, many specialists have also found the phenomenon that there is little affinity between early anatomically modern Homo sapiens and recent Chinese (Howells, 1993; Wright, 1995; Neves and Pucciarelli, 1998; Stringer, 1999; Brown, 1999).

Various specialists also found that some Chinese fossils show mixtures of features.

Etler (Li and Etler, 1991; Etler, 1996) has studied Homo erectus from Yunxian. He found that the Yunxian specimens not only show ‚Mongoloid‘ but also ‚Western archaic‘

features. The Western archaic features, including large cranial and facial dimensions, lack of well-expressed ectocranial buttressing features, elevation of the upper margin of the temporal squama, swept-back orientation of the supraorbital tori, and reduced postorbital constriction appear together with many features common for Homo erectus. Another specialist pointed out that the features shown by archaic Homo sapiens from Maba and Jinniushan are problematic (Pope, 1992). Jinniushan is the most northerly located specimen of all Chinese archaic Homo sapiens. It is said to even exhibit Neandertal affinities e.g. in its thin cranial bones that also occur in Steinheim. The Maba specimen from southern China, displays a spherical shape of orbit that would be completely consistent with the Neandertal morphology (see also Wolpoff et al. 1984, Wu and Poirier, 1995). Pope (1992: 287) argues: „It could well have been in „Maba“ times that individuals with rounder orbits entered the Chinese clade. If the Maba had been recovered in Europe, it would have been classified as a Neandertal“. However, Pope added, that this fact seems biogeographically illogical, but on chronophenetic grounds it is an accurate observation.

In 1988, a nearly complete hominid skeleton was discovered in Laishui, Hebei and dated to 28.000 years ago (Etler, 1996). Bräuer (in press) argues that the Laishui hominid could represent the first evidence that around 30.000 or 40.000 years ago archaic humans were still living in China and possibly co-existing with early anatomically moderns.

According to Etler (1996), this material helps to fill in the gap between late premoderns such as Xujiayao and early moderns, such as the Upper Cave specimens. However, as already mentioned, the affinities of the Upper Cave specimens to recent Chinese are dubious. Therefore, a detailed study of the Laishui hominids would be of great interest.

According to the Multiregional model, the heterogeneity among the fossil hominids would be interpreted as resulting from local differentiation (Wolpoff et al., 1984;

Wolpoff, 1999). Based on the results of this study and reinforced by other recent research, it may be interpreted that during the Middle and Late Pleistocene the populations were highly variable. This variability within ancient Chinese might be due to contact between eastern and western populations (Eurasian and North Asian), when the Mode 2 (bifacial tradition) was introduced to the most northeastern populations in China ( Foley and Lahr, 1997: 23). Based on his archaeological study, Olsen (1999; see also Velichko, 1999) argues that Siberia may have been witness to substantially more complex demographic movements in the Middle and Late Pleistocene in agreement with Foley and Lahr. During this time there were separate population migrations through this region, indicating that this area can be described as a „cross-road“.

If the results from studies of both ancient and recent Chinese populations are combined, it can be seen that the Chinese populations are rather heterogenous. A gradual evolution can hardly be demonstrated. China seems to be a „meeting place“ for the different waves of migration. Applying Lahr‘s multiple dispersal model as an explanation for this situation indicates that the populations that migrated to China might have derived from different waves of migration and from different regions with their own characters.

Thus, the results of the present study appear to be in agreement with an extra-regional origin of the modern Chinese population, as suggested by the Out-of-Africa model. The process of differentiation of the first humans is explained by Harpending et al. (1993) who proposed ‚The Weak Garden of Eden‘ theory, in which they suggest that modern humans spread into separate regions from a restricted source around 100.000 years ago, at which time they passed through population bottlenecks. Around 50.000 years ago, modern human populations were dispersed in Africa and later migrated to Eurasia and East Asia.

Lahr and Foley (1998: 167) explain that the ancestral modern population was not homogenous for long, as population expansion, subdivision, and contraction subsequently took place. Depending on the balance of ancestral polymorphisms throughout the range of the ancestral population prior to subdivison, the pattern of synapomorphism among subdivided groups may have been very different.

Climate changes play a big role for the process of differentiation. An explanation for such differentiation is proposed by Ambrose (1998: 623), who suggests that climatic and geological changes provide an alternative hypothesis for Late Pleistocene population bottlenecks and expansions. Furthermore he said: „The last glacial period was preceded by one thousend years of the coldest temperatures of the Later Pleistocene (71-70 ka), apparently caused by the eruption of Toba, Sumatra, that was known as the largest explosive eruption of the Quartenary“. Furthermore, Ambrose reveals that the end of the bottleneck could have occured either at the end of this hypercold phase, or 10.000 years later, at the transition from cold oxygen isotope 4 to warmer stage 3. According to Ambrose, Toba‘s volcanic winter could have decimated most modern human populations, especially outside of isolated tropical refugia. The largest populations surviving through this bottleneck should have been found in the largest tropical refugia, and thus in equatoral Africa.

It is likely that the evolution of the ancient populations in China was influenced by migrations from outside. Nevertheless, the „archaic Chinese“ developed some characters in response to the process of local adaptation, selection, drift and gene flow which led to a morphology different from Neandertals and archaic Africans.