5 Discussion and conclusions
5.2 Is there regional continuity in East Asia?
The Multiregional Evolution model proposes that modern populations evolved in different geographic areas from already differentiated ancestral groups of archaic Homo sapiens (or Homo erectus). The hypothesis is based primarily on anatomical features that appear to indicate genetic continuity across the archaic/modern human boundary throughout the Pleistocene in Europe as well as in Africa and particularly in the Far East.
The hypothesis stemmed from attempts to relate the morphological differences seen in Homo erectus remains from northern and southern portions of East Asia to the morphological differences between the present day populations from these regions. To some extent, the geographical distribution of human variation reflects the immediate consequences of the dispersals and population movements towards the end of the Early Pleistocene. It has long been recognized that differences between populations are inevitable when a species is widespread, especially when populations occupy different habitats. This is a consequence of isolation by distance (Wolpoff et al., 1984: 447; Smith et al., 1989a: 39; Thorne and Wolpoff, 1992: 77; Wolpoff, 1999). The proponents of this model assume that the evidence of the fossil records in East Asia and Australasia supports their model. Thorne (1981, see also Thorne and Wolpoff, 1981) suggested that this pattern applies to human populations from the Early Pleistocene, after the first colonizations out of Africa. He proposes that:
Centre and edge: The human fossil populations sampled at what were the peripheries of the range at that time, places such as Central Java, were far more homogenous than samples from the center (eastern Africa where Homo sapiens first was successful). Early populations in various peripheral regions had quite different combinations of relatively
homogenous features, often different character states of the same anatomy. Some of the homogenous features at the peripheries that differed from place to place could be linked to common characteristics found in populations from the same areas today (Wolpoff, 1999: 42). The differences between populations in different regions and the relative homogeneity within them are a consequence of this process.
Regional continuity: The maintenance of the contrasting pattern of central and peripheral variation for a long period of time. Furthermore, Wolpoff (1999: 42) explains that, as the more peripheral regions were colonized, populations were subject to harsher conditions and climatic fluctuations of greater magnitudes than at the centre. Numerous local extinctions and recolonizations from nearby areas created a population structure in which broad regional continuity could be expected.
Over the last two decades many attempts to assess the correctness of the Multiregional Evolution model have been undertaken (Howells, 1973, 1989, 1993;
Kamminga and Wright, 1988; Groves, 1989; Smith, 1989; Pope, 1991, 1992; Bräuer, 1984, 1992; Habgood, 1992; Stringer, 1992, 1999; Wu, 1992, 1995, 1997; Lahr, 1994, 1996; Etler, 1991; 1996; Neves and Pucciarelli, 1998). Most of the results of these studies criticized the Multiregional model strongly, particularly the morphological evidence. It is argued that there is a gap for 100.000 years between archaic specimens like Dali, Maba and Jinniushan; and early modern Homo sapiens like Longtanshan, Liujiang and Upper Cave (Bräuer, 1992). Moreover, the Upper Cave specimens and Liujiang have been recently reexamined. The results indicate that these fossils do not show morphological affinities to recent Chinese. Instead, these early modern humans were found to be closer to Africans, Australo-Melanesians and South Americans. The presence of regional continuity features among the recent Chinese is also problematic. A number of both East Asian and Australasian regional features which are supposed to characterize these regions were not supported by recent studies. The majority of these features are not present in these regions. Instead, these features occur geographically widespread, so that they cannot be regarded as characteristic for these regions.
More criticism came from recent dating evidence. Swisher et al. (1996) and Grün et al.
(1999) presented very recent dates of around 40.000 years for Ngandong (Java) and dates of around 50.000 for the gracile modern skeleton from Lake Mungo 3, Australia. If the new dates are correct, Ngandong can hardly be an ancestor of recent Australians which would be even older. This and other evidence (Bräuer and Stringer, 1997) makes the Multiregional Evolution view more and more problematic.
The current results concerning the genetic evidence mostly support the Out-of-Africa model. Studies of mtDNA and nuclear DNA generally show that Africa is the likely place of modern human origin (Cann et al, 1987; Cavalli-Sforza, 1994; Horai, 1995; Nei, 1996).
However, the supporters of the Multiregional Evolution model argue that if modern humans arose first in Africa and then spread out of Africa and replaced the populations that already existed, including those in China, a similar lithic tradition should also be found in this region (Frayer, et al., 1993). As has been mentioned by Lahr and Foley (1997, see also Schick and Zhuan, 1993), archaeological evidence is widely lacking in China. One explanation why the archaeological evidence in China is relatively small might be the so-called ‘Bamboo barrier’ (Pope, 1989, see also Foley and Lahr, 1997). It is supposed that modern humans could exploit bamboo as an alternative material for making tools which, however, are not preserved. Klein (2000: 23) proposes: “By 600 to 500 ky ago, the Acheulean occupied a vast area, from the southern tip of Africa to England and from Spain to India. However, it failed to penetrate eastern Asia. One possibility is that the first east Asians were Oldowan people who expanded from Africa 1.8 to 2 my ago, before the Acheulean emerged. A better-substantiated possibility is that the first east Asians arrived much later, near 1 my ago, but abandoned classic handaxe manufacture early on and subsequently developed their own distinctive artifact tradition. This centered on flakes and a range of relatively informal core tools, perhaps supplemented by novel tools in bamboo. In keeping with archaeological separation from the West by 1 my ago, eastern Asia also seems to have nurtured its own distinctive human lineage or lineages, which persisted from 1 my ago or before until 50 ky ago or later”. Furthermore, Klein argued that, compared to Europe, Africa, and the west Asian bridge that links them, eastern Asia is archaeologically poorly known.
Turning to the evidences of regional continuity in East Asia, some specialists see great problems in the morphological basis. Gradual evolution can not be demonstrated for China (see Stringer, 1992; Bräuer, 1992, 1993; Stringer and Bräuer, 1994; Bräuer and Stringer, 1997; Groves, 1989; Habgood, 1992; Lahr, 1994, 1996; Brown, 1999). As explained above, the present study shows that nearly all of the regional features supposed to be characteristics for Chinese cannot be regarded as convincing. Moreover, the suggested East Asian regional features occur in other modern populations from different parts of the world, often in higher frequencies. Only two tendencies can be seen as recent Chinese or „broad Mongoloid“ features, but these cannot be traced back to the fossils.
Moreover, the fossils themselves are separated from recent Chinese and closer to other populations. It is also evident that there is great heterogeneity among the fossils.
Is there regional continuity in China? On the basis of the current results, a gradual evolution or regional continuity from Homo erectus to modern humans in China can hardly be shown. The Chinese Pleistocene population was strongly variable (Pope, 1992;
Hanihara, 1994; Etler, 1996; Lahr and Foley, 1994). Nevertheless, we can assume that specimens like Liujiang and Upper Cave 101, 102 and 103 belonged to the gene pool from which during the last 20.000 years evolutionary changes towards the morphology of the
recent Chinese and other East Asian populations took place. This process was most likely the result of local adaptation, admixture, genetic drift, absorption and other factors (see also Bräuer, 1992; Hanihara, 1994). Moreover, Hanihara (1994: 436) suggests: “A few Neolithic samples from North China tended to show a craniofacial morphology similar to the recent Chinese samples; this may reflect the possible long-term historical-biological connection resulting from the population movements in the northern part of China at an earlier time”. In his most recent study, Brown (1999) assumed that the recent Chinese morphological pattern has evolved during the Holocene period. This would mean that the recent Chinese morphology was established very recently, as has also been suggested by Stringer (1999).
Chapter 6 Summary
The Multiregional Evolution model suggests for East Asia that modern humans evolved gradually from regional Homo erectus. This hypothesis is based on the fossil record from China and Australasia that is said to show regional continuity. Thus, according to this model, early modern Homo sapiens in each area of the world should strongly resemble recent populations of the same region. The proponents of the Multiregional model believe that high frequencies of ‘regional continuity features’
distinguish these regions from others.
The aim of the present study was to examine whether this suggestion can be supported for China on the basis of eighteen regional continuity features of the face. These features of the face were selected because the suggested ‘Chinese characteristics’ are centered in the face, particularly in the middle and upper face (Pope, 1991). The eighteen assumed regional features are: presence of sagittal keeling on the frontal; pronounced orientation of the malar facies and frontosphenoidal process of the zygomatic bone; anteriorly facing frontal process of the maxilla with distinct paranasal inflation; anterior surface of the zygomatic process faces more forward; junction of the lower margins of the maxilla and the zygomatic bones is more angular in shape; facial height reduction; lower border of the zygomatic process of the maxilla is oriented horizontally; middle part of the face is not very protruding; lack of anterior facial projection and low degree of prognathism;
horizontal course of the nasomaxillary and frontomaxillary sutures; flatness of the nasal saddle; non-depressed nasal root; no difference between upper and middle parts of the nasal bones; presence of the incisura malaris; shape of orbits; rounded infero-lateral margin of the orbit; presence of malar tuberosity; and large naso-malar angle. If the suggestion of the Multiregional Evolution model is correct, these features, or most of them, should occur with high frequency or with pronounced expression in China, and would distinguish the Chinese from other populations. Second, it should be possible to trace back these features to archaic Homo sapiens and Homo erectus.
The occurrence of the suggested East Asian regional features was examined in nine samples from different geographic regions of the world. These include Chinese, Indonesians, Inuit, South Americans, Australo-Melanesians, Polynesians, sub-Saharan Africans, North Africans and Europeans. 256 adult and well-preserved recent crania were studied by examining 18 suggested East Asian regional features of the face which were determined through 25 metrical variables and 11 non-metrical variables. The data were
then analysed statistically by using Anova, Chi-square, and Principal Components Analysis based on raw and log-shape data.
The results can be summarized as follows:
1. The regional continuity features cannot be identified in the modern Chinese sample
The eighteen suggested East Asian regional continuity features occur geographically widespread. An exclusive occurrence of any of these features in China cannot be identified. Moreover, 16 of the features studied do not show the pattern of occurrence or expression as claimed by the Multiregional hypothesis. Only two of the eighteen features show a tendency to occur with pronounced expression as postulated by the Regional Continuity model, although the occurrence of these features in China is not significantly different from that in other populations. These features are the degrees of flatness of the middle and upper face determined by the Zygomaxillary angle and Nasio-frontal angle, respectively.
2. The Inuit are in some features more „East Asian“ than the recent Chinese
Some of the eighteen suggested East Asian regional continuity features are present in Inuit with higher frequencies or with more pronounced expression. These features are:
sagittal keeling on the frontal; anterior orientation of the zygomatic process of maxilla;
middle part of the face is not very protruding; large Naso-malar angle; pronounced orientation of the facies malaris and frontosphenoidal process of the zygomatic bone; non-depressed nasal root; low degree of prognathism. A possible explanation of these conditions is a fairly recent adaptation to biomechanical stress.
3. The expression of the regional continuity features in the fossil hominids is variable
According to the Multiregional model, the features that occur in modern East Asians can be traced back to the fossil hominids of that region. Therefore, as a first step, the two features that occur with relatively pronounced expression in recent Chinese crania (Zygomaxillary angle and Nasio-frontal angle) were examined in the Chinese fossils. The conditions of both features in the fossil crania are variable. Although there is great overlapping between sub-Saharan Africans and Chinese and other samples for the
Zygomaxillary angle, the Homo erectus pekinensis skulls fall with lower values outside the 95% ellipses of the recent Chinese, with lower values. The Upper Cave 103 specimen falls outside the recent populations, whereas Upper Cave 102 lies at the periphery of the sub-Saharan African 95% confidence ellipse. Liujiang and Upper Cave 101 lie in the overlaping zone. For the Nasio-frontal angle, both Homo erectus specimens fall in the zone of overlap between Chinese, sub-Saharan Africans and other populations, as do Liujiang and Upper Cave 101. In contrast, Upper Cave 102 and Upper Cave 103 are at opposite poles and marginal to sub-Saharan Africans and Chinese, respectively.
The examination of the fossils was further extended using three features that are present with higher frequencies in Inuit. These features are: non-depressed nasal root;
pronounced orientation of the malar facies and frontosphenoidal process of the zygomatic bone; and anterior orientation of the zygomatic process of maxilla. With regard to the degree of nasal root depression and orientation of the zygomatic proccess of the maxilla the fossils are highly variable. Concerning the anterior orientation of the malar facies and frontosphenoidal process of the zygomatic bone, all specimens except that of Upper Cave 102 show similar conditions (rather obtuse angles 78°-88°).
4. No affinities between fossil and recent Chinese crania
Multivariate methods used to analyse the affinities between fossil and modern Chinese specimens show that all fossils are widely scattered. Based on a PCA using log-shape data, no individual fossil is closest to the Chinese centroid. The early modern specimen from Liujiang is closer to South Americans and sub-Saharan Africans than to modern Chinese. Upper Cave 102 is closer to North and sub-Saharan Africans, and Homo erectus pekinensis reconstructed by Weidenreich is closer to sub-Saharan Africans as well. Homo erectus reconstructed by Tattersall shows an intermediate position among the modern samples.
5. Chinese features were most likely established recently
As shown in this study, no gradual evolution could be found between Homo erectus, early modern Homo sapiens and recent Chinese. It is assumed that the morphology exhibited by early modern humans such as the Upper Cave and Liujiang specimens changed towards that of recent Chinese during the last 30.000 years. In other words, the recent Chinese might have evolved from the early modern Chinese populations. The origin of these early modern Chinese, however, seems to be located outside this area.
The above results show that the morphological basis for the Multiregional Evolution model is dubious and should be further reviewed. The results of the present study support previous studies that already pointed to the weak basis of this model. In agreement with Lahr’s suggestion (1996; see also Bräuer and Stringer, 1997), the definition of many features needs also to be revised in order to reach worldwide agreement.
7 References
Aiello, L. (1993). The fossil evidence for modern human origins in Africa: A revised view. Am. Anthropologist 95(1), 73-96
.Aiello, L. & Dean, C. (1990). An Introduction to Human Evolutionary Anatomy. San Diego: Academic Press.
Aigner, J. S. (1986). The age of Zhoukoudian locality 1: the newly proposed 018 correspondences. Fossil Man-New Facts, New Ideas (Anthropos) 23, 157-173. Brno.
Aigner, J. S. & Laughlin, W. S. (1973). The dating of Lantian man and his significance for analyzing trends in human evolution. Am. J. Phys. Anthrop. 39, 97-110.
Alexseev, V. P. (1979). Anthropometry of Siberian peoples(W. Laughlin & Harper, Eds.), pp. 57-90.
Ambrose, S. (1998). Late Pleistocene human population bottlenecks, volcanic winter, and differentiation of modern humans. J. Hum. Evol. 34, 623-651.
Aziz, F., H. Baba & N. Watanabe. (1996). Morphological study on the Javanese Homo erectus Sangiran 17 skull based upon the new reconstruction. Palaeontology series (8), 27-40.
Bass, W. M. (1971). Human Osteology. Knoxville, Tennesse: The Missouri Archaeological society, Inc.
Beals, K. L. (1972). Head form and climatic Stress. Am. J. Phys. Anthrop. (37), 85-92.
Bilsboroough, A. & Wood, B. A. (1972). Cranial morphometry of early Hominids: Facial region. Am. J. Phys. Anthrop. (76), 61-86.
Brace, L. C. & David P. T. (1996). Craniofacial continuity and change: A comparison of Late Pleistocene and recent Europe and Asia. In (T. Akazawa & E. Szathmary, Eds.) Prehistoric Mongoloids dispersals, pp. 439-471. Oxford: Oxford University Press.
Brace, L. C. & Hunt, K. (1990). A nonracial craniofacial perspective on human variation:
A(ustralia) to Z(uni). Am. J. Phys. Anthrop. 82, 341-360.
Bräuer, G. (1981). New evidence on the transitional period between Neanderthal and modern man. J. Hum. Evol. 10, 467-474.
Bräuer, G. (1984a). The Afro-Europeans sapiens-hypothesis, and hominid evolution in Asian during the late Middle and Upper Pleistocene. In (P. Andrews & J. Franzen, Eds.) Cour. Forsch. Inst. Senckenberg. Vol 69: The early evolution of man with special emphasis on Souteast Asia and Africa. Frankfurt am Main.
Bräuer, G. (1984b). A craniological approach to the origin of anatomically modern Homo sapiens in Africa and implications for the appearance of modern Europeans. In ( Smith F.H. & F. Spencer, Eds.) The Origin of Modern Humans: A World survey of the fossil evidence, pp. 327-410. New York: Alan R. Liss.
Bräuer, G. (1984c). Präsapiens-Hypothese oder Afro-europäische Sapiens-Hypothese? Z.
Morph. Anthr. (75), 1-25.
Bräuer, G. (1992). The origins of modern Asians: By regional evolution or by replacement? In (T. Akazawa, T. Aoki & T. Kimura, Eds.) The evolution and dispersal of modern human in Asia, pp. 405-413. Hokusen-Sha: Hokusen-Sha publishing Co.
Bräuer, G. (1994). How different are Asian and African Homo erectus? Cour.
Forsch.-Inst. Senck. (171), 301-318.
Bräuer, G. (in press). The „Out-of-Africa“ Model and Question of Regional continuity.
Bräuer, G. & Mbua, M. (1992). Homo erectus features used in cladistics and their variability in Asian and African hominids. J. Hum. Evol. 22, 79-108.
Bräuer, G. & Stringer, C. (1997). Models, polarization, and perspectives on modern human origins. In (G. Clark & C. Willermet, Eds.) Conseptual issues in modern human origin research, pp. 191-201. New York: Aldine de Guyter.
Brown, P. (1993). Recent human evolution in East Asia. In (S. Aitken, Mellars, Ed.) The origin of modern humans and the impact of chronometric dating, pp. 217-233. New Jersey: Princeton university press.
Brown, P. (1994). Cranial vault thickness in Asian Homo erectus and Homo sapiens.
Cour. Forsch.-Inst. Senck. (171), 33-46.
Brown, P. (1999). The first modern East Asians?: another look at Upper Cave 101, Liujiang and Minatogawa 1. In ( K. Omoto, Ed.) Interdisiplinary perspectives on the origins of the Japanese, pp. 105-130. Kyoto: International research center of Japanese studies.
Cann, L. R., Richards, O. & Lum, K. (1994). Mitochondrial DNA and Human Evolution:
Our one lucky mother. In ( Nitecki & Nitecki, Eds.) Origin of anatomically modern humans., pp. 135-147. New York: Plenum Press.
Cann, L. R., Stoneking, M. & Wilson, A. C. (1987). Mitochondrial DNA and Human Evolution. Nature 235, 31-36.
Carbonell, E., Mosquera, M., Rodriquez, X., Sala & R. (1999). Out of Africa: the dispersal of the earliest technical systems reconsidered. Journal of Anthropological Archaeology 18, 119-136.
Caspari, R. & Wolpoff, M. (1996). Weidenreich, Coon, and multiregional evolution. J.
Hum. Evol. 11(3-4), 261-268.
Cavalli-Sforza, L. L. (1992). Stammbäume von Völkern und Sprachen. Spektrum der Wissenschaft (1), 90-98.
Cavalli-Sforza, L., Menozzi, P. & Piazza, A. (1994). The History and Geography of Human Genes. Princeton: Princeton University Press.
Chen, T. & Zhang, Y. (1991). Palaeolithic chronology and possible coexistence of Homo erectus and Homo sapiens in China. World Archaeology 23(2), 147-154.
Cheverud, J., Kohn, L., Konigsberg, L. & Leigh, S. (1992). Effects of fronto-occipital artificial cranial vault modification on the cranial base and face. Am. J. Phys. Anthrop.
88, 323-345.
Churchill, S. (1998). Cold adaptation, heterochrony, and Neanderthals. Evol. Anthrop.
7(2), 47-61.
Clark, D. (1993). African and Asian perspectives on the origins of modern humans. In (M.
Aitken, C. Stringer & P. Mellars, Eds.) The origin of modern humans and the impact of chronometric dating, pp. 148-178. New Jersey: Princeton university press.
Clark, L., W.E. (1964). The fossil evidence for human evolution. Chicago: The university of Chicago press.
Coon, C. S. (1962). The Origin of Races. New York: Knopf.
Corruccini, R. S. (1976). The interaction between nonmetric and metric cranial variation.
Am. J. Phys. Anthrop. 44, 285-294.
Corruccini, R. S. (1987). Shape in morphometrics: comparative analyses. Am. J. Phys.
Anthrop. 73, 289-303.
Cronin, J., Boaz, N., Stringer, C. & Rak, Y. (1981). Tempo and mode in hominid evolution. Nature 292, 113-122.
Czarnetzki, A. (1994). Morphological variability of Homo erectus as an Indication of a genetic predisposition of phylogenetic changes. Cour. Forsch.-Inst. Senck. (171), 295-298.
Demes, B. & Creel, N. (1988). Bite force, diet, and cranial morphology of fossil hominids. J. Hum. Evol. 17, 657-670.
Enlow, D. H. (1966). A comparative study of facial growth in Homo and Macaca. Am. J.
Phys. Anthrop. (24), 293-308.
Etler, D. A. (1994). The Chinese Hominidae: New finds, new Interpretations. California:
Dissertation (unpublished).
Etler, D. A. (1996). The fossil evidence for human evolution in Asia. Annu. Rev.
Anthropol. 25, 275-301.
Etler, D. A. & Li, T. (1992). New archaic human fossil discoveries in China and their bearing on hominid species definition during the Middle Pleistocene. In ( Corruccini R.S. & R. L. Chiochon, Eds.) Integrative paths to the past. New Jersey: Prentice Hall.
Flury, B. & Riedwyl, H. (1983). Angewandte multivariate Statistik. Stuttgart: Gustav Fischer Verlag.
Foley, R. (1996). The adaptive legacy of human evolution: a search for the environment of evolutionary adaptedness. Evol. Anthrop. 4(6), 195-203.
Foley, R. & Lahr, M. (1997). Mode 3 technologies and the evolution of modern humans.
Cambridge Archaeological Journal 7(1), 3-36.
Fox, C., Hernandez, M. & Moro, G. (1996). Craniometric analysis in groups from Tierra del Fuego/Patagonia and the peopling of the South Americas. Hum. Evol. II(3-4), 217-224.
Fransiscus, R. & Trinkaus, E. (1988). Nasal morphology and the emergence of Homo erectus. Am. J. Phys. Anthrop. 75, 517-527.
Frayer, D. W. (1984). Biological cultural change in the European Late Pleistocene and Early Holocene(F. Smith & F. Spencer, Eds.), pp. 211-250. New York: Allan R. Liss.
Frayer, D. W., Wolpoff, M., Thorne, A., Smith, F. & Pope, G. (1993). Theories of modern human origins: The paleontological test. Am. Anthropologist 95(1), 14-50.
Frayer, D. W., Wolpoff, M., Thorne, A., Smith, F. & Pope, G. (1994). Getting it straight.
Am. Anthropologist 96, 424-438.
Greenberg, J., Turner II, C. & Zegura, S. (1986). The settlement of the Americas: A comparison of the linguistic, dental, and genetic evidence. Current Anthropology 27(5), December, pp. 477-497.
Groves, C. (1989). A regional approach to the problem of the origin of modern humans in Australasia. In (P. Mellars & C. Stringer, Eds.) The human revolution: behavioural and biological perspectives on the origin of modern humans, pp. 275-285. Edinburgh University Press.
Grün, R., Hua, H., Wu, X., Stringer, C., Thorne, A. & McCulloch. (1997). ESR analysis of teeth from the Palaeoanthropological site of Zhoukoudian, China. J. Hum. Evol. 32, 83-91.
Guglielmino-Matessi, C., Gluckman, P. & Cavalli-Sforza, L. (1979). Climate and the evolution of skull metrics in man. Am. J. Phys. Anthrop. 50, 549-564.
Habgood, P. J. (1985). The origin of the Australian Aborigines: An alternative approach and view. In (T. Phillip, Ed.) Hominid evolution: past, present and future, pp. 367-380.
Allan R. Liss.
Habgood, P. (1989). The origin of anatomically modern human in Australasia. In (C.
Stringer & P. Melars, Eds.) The human revolution, pp. 245-2273. Princeton, New Jersey: Princeton University Press.
Habgood, P. (1992). The origin of anatomically modern human in East Asia. In (G.
Bräuer & F. Smith, Eds.) Continuity or Replacement: controversies in Homo sapiens evolution, pp. 273-288. Rotterdam: A.A. Balkema.
Haeseler, A., Sajantila, A. & Pääbo, S. (1996). The genetical archaeology of the human genome. Nature Genetics 14, 135-140.
Hanihara, T. (1992). Dental and cranial affinities among populations of East Asia and the Pacific: The basic populations in East Asia IV. Am. J. Phys. Anthrop. 88, 163-182.
Hanihara, T. (1994). Craniofacial continuity and discontinuity of Far Easterners in the Late Pleistocene and Holocene. J. Hum. Evol. (27), 417-441.
Hanihara, T. (2000). Frontal and facial flatness of major human populations. Am. J. Phys.
Anthrop. 111, 105-134.
Hannam, A. & Wood, W. W. (1981). Medial pterygoid muscle activity during the closing and comprehensive phases of human mastication. Am. J. Phys. Anthrop. 55, 359-967.
Hannam, A. & Wood W. W. (1989). Relationships between the size and spatial morphology of human masseter and medial pterygoid muscles, the craniofacial skeleton, and jaw biomechanics. Am. J. Phys. Anthrop. 80, 429-445.
Harpending et al. (1993). The genetic structure of ancient human populations. Current Anthropology 34(4), 483-496.
Henke, W. & Rothe, H. (1994). Palaeoanthropologie. Berlin, New York: Springer.
Hertha De Villiers. (1968). The Skull of the South African Negro. Johannesburg:
Witwatersrand University press.
Horai, S., Hayasaka, K., Kondo, R., Tsugane, K. & Takahata, N. (1995). Recent African origin of modern humans revealed by complete sequences of hominoid mitochondrials DNAs. Proc. Natl. Acad. Sci.USA 92, 532-536.