Dental morphology and the population history of the Pacific rim and basin Commentary on Hirofumi Matsumura and Mark J. Hudsonкод для вставкиСкачать
AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 130:455–461 (2006) Notes and Comments Dental Morphology and the Population History of the Paciﬁc Rim and Basin: Commentary on Hirofumi Matsumura and Mark J. Hudson Christy G. Turner II* School of Human Evolution and Social Change, Arizona State University Tempe, Arizona KEY WORDS Asian-Paciﬁc human origins; dental morphology; sundadonty; sinodonty Matsumura and Hudson (2005) critique the dental morphological inferences and hypotheses that I developed for the late Pleistocene and Holocene population history of Southeast Asia (Turner, 1983, 1986a,b, 1987, 1990a,b, 1992a,b, 1995, and elsewhere). They propose abandoning my local-evolution hypothesis called ‘‘sundadonty and sinodonty,’’ and returning to an earlier view of ‘‘southern Mongoloid’’ origins, as having been caused by hybridization between Southeast Asian resident Australmelanesians and Neolithic Mongoloid migrant farmers from China (Callenfels, 1936; Mijsberg, 1940; Barth, 1952; von Koenigswald, 1952; Bellwood, 1985). They also propose changing the meaning of ‘‘sundadonty’’ without any corresponding explanation for the origin of sinodonty. I interpreted East Asian dental variation as indicating local evolution of the sundadont dental pattern in Southeast Asia. People possessing this pattern later spread into Northeast Asia. There, most likely in northern China, Mongolia, and southern Siberia, sundadonty evolved into sinodonty, possibly around 30,000 years ago (Turner et al., 2000), and certainly before 13,000 years ago, when High Arctic Paleo-Siberian sinodonts had crossed Beringia into the New World (Haynes, 2002; Fiedel, 2004). Later, in our era, Southeast Asian sundadonts colonized Polynesia and Micronesia. This East Asian dental evolution hypothesis grew out of my dental observations for the entire Paciﬁc Basin and Rim. Scott and Turner (1997) synthesized and classiﬁed much of this information plus other dental morphological variation into ﬁve major worldwide dental groups: sahul-Paciﬁc, sunda-Paciﬁc, Sino-American, subSaharan Africa, and Western Eurasia. These are each substantially different from one another, with sunda-Paciﬁc (Southeast Asia, Polynesia, Micronesia, and JomonAinu) being the most generalized or least divergent of the ﬁve. Local dental evolution was proposed as a standardized diachronic, multiregional, epigenetically based alternative to the hodgepodge of inadequate, out-of-date, and sometimes incorrectly interpreted osteological and archaeological evidence used in support of the Neolithic migration scenario that originated in the era when migrationism was the major explanatory mechanism for modern human biological variation and culture change (Adams et al., 1978). That evidence was reviewed in Turner (1987), and elaborated upon by Bulbeck (1996, 1999, 2000, and elsewhere) and Rayner and Bulbeck (2001). C 2006 V WILEY-LISS, INC. My deﬁnition of sundadonty was based on a set of crown and root traits considerably different from those used by Matsumura and Hudson (2005), who also changed the definitions of incisor shoveling, double-shoveling, and hypocone, and left out major traits such as three-rooted lower ﬁrst molars, four-cusped lower second molars, the pegreduced-congenital absence complex of the upper third molars, and others. My sundadonty was an empirically derived, and widely reported, speciﬁc set of rigorously standardized characters (Turner et al., 1991). These were found in both prehistoric and modern Southeast Asian dentitions, contrary to the claim by Matsumura and Hudson (2005) that their ‘‘sundadonty’’ does not occur in prehistoric Southeast Asians. My frequencies of sundadont traits are not the same in Australians and Melanesians. Changing the deﬁnition of sundadonty is unwarranted. Let me elaborate on this concern. WHAT’S IN A NAME? To change the meaning and features of sundadonty as empirically determined for the morphological characteristics of sunda-Paciﬁc teeth, resulting in the inclusion of Australians and Melanesians, has no justiﬁcation (see interregional trait-frequency differences in Scott and Turner, 1997). I coined the term ‘‘sundadonty’’ on the basis of a widespread dental pattern that I found time and again throughout modern and early archaeological mainland and island Southeast Asia, and later archaeological Polynesia, Micronesia, Jomon Japan, and modern Hokkaido Ainu. ‘‘Sinodonty’’ was the term I coined for the signiﬁcantly different dental pattern that characterized my more northerly East Asian dental samples from northern China, post-Jomon Japan, Mongolia, eastern Siberia, and all of the Americas. Several dental traits set sundadonty and sinodonty apart, but eight were most signiﬁcant (Turner, 1983, 1987, 1990a). In nearly every analysis my associates and I made of Oceanic dentitions from Easter, Guam, Hawaii, and several other Polynesian and Micronesian islands, the teeth ﬁt the sundadont dental pattern, and differed considerably from all of several archaeological and recent Melanesian and Australian dental samples. This fundamental ﬁnding is consistent with the generally accepted two-wave migration hypothesis (non-Austronesian ﬁrst, and Austronesian second) for the colonization of Oceania (Green, 1994). Pietrusewsky (1990, 1996, 2005, and elsewhere) repeatedly found the same fundamental duality of Oceania, based on his many years of Paciﬁc and East Asian prehistoric and historic craniological research. His studies regularly showed Southeast Asian crania to *Correspondence to: Christy G. Turner II, School of Human Evolution and Social Change, Arizona State University, Tempe, AZ 85287-2402. E-mail: firstname.lastname@example.org Received 13 June 2005; accepted 9 August 2005. DOI 10.1002/ajpa.20380 Published online 19 January 2006 in Wiley InterScience (www.interscience.wiley.com). 456 C.G. TURNER II cluster with those from Polynesia and Micronesia, and almost never with crania from Australia or Melanesia. The same can be said of the Asian-Oceanic dental studies of Hanihara (1993). The genetic literature exhibits the same general relationships (Cavalli-Sforza et al., 1994, p. 443–367). Nevertheless, the similarity between sundadonty and the Australian and Melanesian (A-M) dental pattern was sufﬁciently similar to suggest that the A-M pattern could have been like that which existed in Southeast Asia before sundadonty evolved its characteristics. I called that hypothetical pattern ‘‘proto-sundadonty,’’ and suggested that it could have been similar to my pooled average Australian assemblage on the grounds that averaging would adjust for the internal Australian dental divergence produced by drift, founder effect, and population structure. I proposed the term ‘‘proto-sundadonty’’ at a University of Tokyo conference on the evolution and dispersal of modern humans in Asia (Turner, 1992b, p. 429), on the grounds that the ancestors of the Australians had to have originated in Southeast Asia, but long before any of my Southeast Asian dental samples were living people, because Australia was colonized by at least 50,000 years ago. Hanihara (1992) has since used the term ‘‘proto-sundadonty’’ in much the same way, i.e., to suggest an evolutionary grade between that of Australians and Southeast Asians. These facts and inferences help bracket the emergence of sundadonty after 50,000 years ago, but before roughly 10,000 BP, the probable age of my oldest mainland Southeast Asian dental samples. Offshore, the few Minatogawa teeth from Okinawa, dated at 22,000 BP, despite their heavy wear, certainly look as if they could be classiﬁed as sundadonts (they cluster with Jomon teeth; Turner 1987, p. 309), as do a few other highly fragmentary teeth and jaws from the 20,000þ BP Tabon Cave (66-V-121 has a three-rooted lower ﬁrst molar, which is very rare in Australmelanesians) and 40,000 BP Niah Cave (EM805 upper M2 has a strongly reduced hypocone, and possibly a single-rooted upper P1: both Asian, and not Australmelanesian, tendencies). In other words, a very broad view of eastern Asia from the Arctic Circle to the tip of the Malay Peninsula, and the Paciﬁc Basin from Taiwan to Easter, shows without any question that not only did sundadonty exist long before Neolithic Mongoloid farmers spread into Southeast Asia, but sundadonty is so widespread in the Paciﬁc and Southeast Asia that it is difﬁcult to imagine how even large numbers of Chinese farmers could have caused so much genetic mixing. What’s more, no one has ever claimed that the pre-Yayoi Jomonese of Japan were inﬂuenced by Chinese farmers, yet they have the sundadont pattern. Hawkey (1998) found that 22,000-year-old teeth from Sri-Lanka correspond well with the sundadont pattern, providing a sundadont-like sample far, far away in time and space from any Neolithic Chinese farmers. My guess is that sundadonty is around 25,000–40,000 years old, and its geogenetic hub is in Australasia (Southeast Asia and eastern South Asia). This I suggest on the grounds that, in contrast, sinodonty has to be younger than sundadonty, and had to have evolved out of sundadonty, because there is no other dental pattern in the world as much like sinodonty as sundadonty. In short, the most parsimonious explanation for sundadonty, based on direct and indirect evidence, indicates that it existed before the Neolithic, and I maintain that overwhelming amounts of evidence and strong inferences indicate that it is the result of local evolution out of proto-sundadonty for the reasons just stated, and not the result of admixture between unmigrated Australmelanesians and Northeast Asian peoples. While the inference made by Matsumura and Hudson (2005) is not unreasonable, i.e., very early Southeast Asian teeth should show some similarity with those of Australmelanesians, their inference was anticipated more than a decade ago by the hypothesis of protosundadonty, which they do not acknowledge. DENTAL WEAR Sundadonty and sinodonty are relative concepts. The former is more simpliﬁed and retains more of the inferred ancestral proto-sundadont condition as reconstructed on the basis of Australian dental morphology and earlier teeth from Africa and Europe, i.e., early anatomically modern humans. For example, sundadonty has a higher frequency of four-cusped lower second molars (simpliﬁcation), and a lower frequency of three-rooted lower ﬁrst molars (less specialized). Sinodonty is more complex and specialized; again, 3-rooted lower ﬁrst molar has a very high frequency. However, with occlusal wear, some of the crown morphological expression of sinodonty can wear off, leaving individuals who appear to be sundadonts. I have found this ‘‘shift’’ repeatedly in Native Americans. All Native Americans are sinodonts, but within any given dental sample, the crowns of older individuals with varying amounts of wear can take on a sundadont appearance, although the roots do not. For example, incisor shoveling can shift from marked to moderate with wear. The canine distal accessory ridge can shift from marked to absent with wear. Lower molar cusp 6 can wear off completely. Aware of this source of observational error, we established strict limits on the amount of occlusal wear that is allowed for trait scoring in the Arizona State University Dental Anthropology System (Turner et al., 1991). Archaeologically derived teeth generally show more dental wear than teeth of recent or living people, which is a simple function of tooth use and food-processing technology. The fact that Matsumura and Hudson (2005) found prehistoric Southeast Asian teeth to be more like the relatively simple teeth of Australians and Melanesians is in part attributable to the fact that they did not take wear into account; at least they say nothing about wear being considered. To illustrate the problem, Matsumura and Hudson (2005) scored lower molar cusp 6 the same way that Scott and Turner (1997) did, yet their frequency of cusp 6, in Australmelanesians, for example, is 28–38%, whereas we reported 14–72%. Where attrition is less of a problem, e.g., in the interruption groves of the upper lateral incisors, located near the crown-root junction, our Australmelanesian ﬁndings are more alike: Matsumura and Hudson (2005), 13–24%; Scott and Turner (1997), 8– 28%. One of their prehistoric Southeast Asian samples (Non Nok Tha) clusters with their New Britain sample. This is much more likely due to occlusal wear or choice of traits than to phylogeny, because neither Pietresewsky (1996) nor I found Non Nok Tha crania or teeth to cluster closely with New Britain or any other Melanesian or Australian sample. SOUTHEAST ASIAN POPULATION POORLY DEFINED Figure 1 (cladogram) and Figure 2 (multidimensional scaling) in Matsumura and Hudson (2005) placed Sakhalin Ainu, Hokkaido Ainu, and Jomon Japanese in the group titled ‘‘Australians, Melanesians, and prehistoric DENTAL MORPHOLOGY IN PACIFIC RIM AND BASIN Southeast Asians.’’ Of course, the Japanese are neither Australian, Melanesian, nor prehistoric Southeast Asian, so a meaningful part of their clustering and classiﬁcation is geogenetically incorrect (3/13 groups; 23.1%). The joining of prehistoric Southeast Asians with Jomonese and Ainu is to be expected, since they all possess sundadont morphology and share similar archaeological elements including shell mounds, dental transﬁgurement, and early pottery. The problem is with the Australians and Melanesians, who are misclassiﬁed. Only by ignoring the fact that the three Ainu-Jomon samples link with the prehistoric Southeast Asians can Matsumura and Hudson (2005) claim that prehistoric Southeast Asians are more like Australians and Melanesians, and hence that modern Southeast Asians are a product of mixing with Neolithic farmers from the north. One group in island Southeast Asia that the hypothetical Chinese farmers could not possibly have had much effect on are the Batak, a so-called ‘‘Negrito’’ hunting-andgathering forest people of the Philippines often said to resemble Australmelanesians, although smaller in stature. Using the multivariate mean measure of divergence statistic (MMD) shows that a sample of Batak teeth is most similar to Southeast Asians and least similar to Australmelanesians and Africans: Batak/Prehistoric Taiwan, MMD ¼ 0.03; Philippines, MMD ¼ 0.06; Early Malay Archipelago, MMD ¼ 0.07; Borneo, MMD ¼ 0.08; Ban Chiang, MMD ¼ 0.08; Sri Lanka, MMD ¼ 0.09; Central Thailand, MMD ¼ 0.10; early mainland Southeast Asia, MMD ¼ 0.11; Australia-Tasmania, MMD ¼ 0.19; Melanesia, MMD ¼ 0.27; Nubia, MMD ¼ 0.31; West Africa, MMD ¼ 0.38 (Turner and Eder, 2005). The Batak provide no support for the Neolithic migration model to explain the origin of ‘‘southern Mongoloids.’’ The ﬁrst person whom I found to challenge the migrating farmer hypothesis did so by diachronic cranial comparisons. Sangvichien (1983) examined some of the same crania that Matsumura and Hudson (2005) later reported on, and compared them with recent Thai. Sangvichien (1983) found very little difference, and concluded that the Thai are an indigenous Southeast Asian population, and not migrants from the north as are modern Chinese in Thailand. TOOTH SIZE PROBABLY REFLECTS TECHNOLOGY AS WELL AS PHYLOGENY Ignoring the very small size of the prehistoric Southeast Asian sample of Matsumura and Hudson (2005) (e.g., only 59 mesiodistal measurements for the upper teeth, with a range of 1–8 mesiodistal measurements for any given tooth), an examination of the dental measurements they provided, especially their Figure 3, reveals that teeth are generally ‘‘smaller’’ in Northeast Asia than in Southeast Asia. This situation brings to mind the study by Perzigian (1984), whose cluster analysis demonstrated on a worldwide basis that small-toothed people group together regardless of location, language, or genetic afﬁnity. The same sort of clustering occurred for large-toothed folk. Perzigian (1984) thought that this classiﬁcation better reﬂected dentally related technology than genetic afﬁnity. On the other hand, his cluster analysis of dental shape produced groupings that would be expected on the basis of known taxonomic relationships. Similarly, Brace et al. (1990, p. 339) linked the relatively small teeth of Jomonese, Chinese, Neolithic Thai, and others to food-processing technology. The crown measurements that Matsumura 457 and Hudson (2005) used to support the idea of a Neolithic farming migration are susceptible to alternative interpretations like that of Perzigian (1984). Moreover, in their effort to show that recent Southeast Asians are hybrids of Northeast Asians and unmigrated Australmelanesians, it should be noted that they have two prehistoric Southeast Asian groups whose tooth ‘‘size’’ links them with recent Southeast Asians: Early Holocene Laotians and Ban Kao. In conclusion, it is my view that Matsumura and Hudson (2005) have not overthrown the sundadont (and sinodont) model for the late Pleistocene and Holocene population history of Southeast Asia, let alone its contribution to the understanding of all East Asian, Oceanic, and Native American dental variation. They have, in fact, strengthened it with useful additional data. ACKNOWLEDGMENTS I thank David Bulbeck in Canberra, Australia, for taking considerable time to ‘‘discuss’’ this commentary with me through the remarkable medium of e-mail. Any errors herein are mine. LITERATURE CITED Adams WY, Van Gerven DP, Levy RS. 1978. The retreat from migrationism. Annu Rev Anthropol 7:483–532. Barth F. 1952. The southern Mongoloid migration. Man 52:5–8. Bellwood P. 1985. Prehistory of the Indo-Malaysian archipelago. Sydney: Academic Press. Brace CL, Brace ML, Dodo Y, Hunt KD, Leonard WR, Yongyi L, Sangvichien S, Xiang-Qing S, Zhenbiao Z. 1990. Microneisans, Asians, Thais and relations: a craniofacial and odontometric perspective. In: Hunter-Anderson RL, editor. Recent advances in Micronesian archaeology. Micronesica supplement no. 2. Mangilao: University of Guam Press. p 323–348. Bulbeck D. 1996. Holocene biological evolution of the Malay Peninsula Aborigines (Orang Asli). Perspect Hum Biol 2:37–61. Bulbeck D. 1999. Current biological anthropological research on Southeast Asia’s Negritos. SPAFA J 9:15–22. Bulbeck D. 2000. Dental morphology at Gua Cha, West Malaysia, and the implications for ‘‘sundadonty.’’ Indo Pacif Prehist Assoc Bull 19:17–41. Callenfels PVS. 1936. The Melanesoid civilizations of eastern Asia. Rafﬂes Mus Bull 1:41–51. Cavalli-Sforza LL, Menozzi P, Piazza A. 1994. The history and geography of human genes. Princeton, NJ: Princeton University Press. Fiedel S. 2004. The Kennewick follies: ‘‘new’’ theories about the peopling of the Americas. J Anthropol Res 60:75–110. Green R. 1994. Changes over time: recent advances in dating human colonisation of the Paciﬁc Basin area. In: Sutton DG, editor. The origins of the ﬁrst New Zealanders. Auckland: Auckland University Press. p 1–33. Hanihara T. 1992. Negritos, Australian Aborigines, and the ‘‘proto-sundadont’’ dental pattern: the basic populations in East Asia, V. Am J Phys Anthropol 88:183–196. Hanihara T. 1993. Dental afﬁnities among Polynesian and circum-Polynesian populations. Jpn Rev 4:59–82. Hawkey DE. 1998. Out of Asia: dental evidence for microevolution and afﬁnities of early populations from India/Sri Lanka. Ph.D. dissertation, Anthropology, Arizona State University, Tempe. Haynes G. 2002. The early settlement of North America: the Clovis era. Cambridge: Cambridge University Press. Matsumura H, Hudson MJ. 2005. Dental perspectives on the population history of Southeast Asia. Am J Phys Anthropol 127:182–209. Mijsberg WA. 1940. On a Neolithic Palaeo-Melanesian lower jaw found in a kitchen midden at Gua Kepah, Province Wellesley, Straits Settlements. In: Chasen FN, Tweedie MWF, editors. Proc III Cong Prehist Far East. Singapore. p 100–118. 458 C.G. TURNER II Perzigian AJ. 1984. Human odontometric variation: an evolutionary and taxonomic assessment. Anthropologie 22:193–198. Pietrusewsky M. 1990. Craniometric variation in Micronesia and the Paciﬁc: a multivariate study. In: Hunter-Anderson RL, editor. Recent advances in Micronesian archaeology. Micronesica supplement no. 2. Mangilao: University of Guam Press. p 373–402. Pietrusewsky M. 1996. Multivariate craniometric investigations of Japanese, Asians, and Paciﬁc islanders. In: Omoto K, editor. Interdisciplinary perspectives on the origins of the Japanese. International symposium 1996. Kyoto: International Research Center for Japanese Studies. p 65–104. Pietrusewsky M. 2005. The physical anthropology of the Paciﬁc, East Asia and Southeast Asia: a multivariate craniometric analysis. In: Sagart L, Blench R, Sanchez-Mazas A, editors. The peopling of East Asia: putting together archaeology, linguistics and genetics. London: Routledge Curzon. Rayner D, Bulbeck D. 2001. Dental morphology of the ‘‘Orang Asli’’ aborigines of the Malay Peninsula. In: Henneberg M, editor. Causes and effects of human variation. Adelaide: Australian Sociery for Human Biology. p 19–41. Sangvichien S. 1983. Problems concerning Thai migrations. Bangkok: Prehistoric Museum Mahidol University. Scott GR, Turner CG II. 1997. The anthropology of modern human teeth: dental morphology and its variation in recent human populations. Cambridge: University of Cambridge Press. Turner CG II. 1983. Sinodonty and sundadonty: a dental anthropological view of Mongoloid microevolution, origin, and dispersal into the Paciﬁc Basin, Siberia, and the Americas. In: Vasilevsky RS, editor. Late Pleistocene and early Holocene cultural connections of Asia and America. Novosibirsk: USSR Academy of Science, Siberian Branch. p 72–76 [in Russian]. Turner CG II. 1986a. Recent Hong Kong dentition: a probable southern afﬁnity. J Hong Kong Archaeol Soc 11:142–146. Turner CG II. 1986b. The ﬁrst Americans: the dental evidence. Nat Geogr Res 2:37–46. Turner CG II. 1987. Late Pleistocene and Holocene population history of East Asia based on dental variation. Am J Phys Anthropol 73:305–321. Turner CG II. 1990a. The major features of sundadonty and sinodonty, including suggestions about East Asian microevolution, population history, and late Pleistocene relationships with Australian Aboriginals. Am J Phys Anthropol 82:295– 317. Turner CG II. 1990b. Origin and afﬁnity of the people of Guam: a dental anthropological assessment. In: Hunter-Anderson RL, editor. Recent advances in Micronesian archaeology. Micronesica supplement no. 2. Mangilao: University of Guam Press. p 403–416. Turner CG II. 1992a. The dental bridge between Australia and Asia: following Macintosh into the East Asian hearth of humanity. Archaeol Oceania (Perspect Hum Biol 2) 27:143– 152. Turner CG II. 1992b. Microevolution of East Asian and European populations: a dental perspective. In: Akazawa T, Aoki K, Kimura T, editors. The evolution and dispersal of modern humans in Asia. Tokyo: Honkusen-Sha Publishing Co. p 415– 438. Turner CG II. 1995. Shifting continuity: modern human origin. In: Brenner S, Hanihara K, editors. Oxnard CE, series editor. The origin and past of modern humans as viewed from DNA—theoretical approach, Kyoto, 14–17 December, 1993, International Institute for Advanced Studies. Recent advances in human biology, volume 1. Singapore: World Scientiﬁc. p 216–243. Turner CG II, Eder JF. 2005. Batak dentition, Palawan Island, Philippines. In: Oxenham M, Tayles N, editors. Bioarchaeology of Southeast Asia area. Cambridge: Cambridge University Press. p 172–187. Turner CG II, Nichol CR, Scott GR. 1991. Scoring procedures for key morphological traits of the permanent dentition: the Arizona State University dental anthropology system. In: Kelley MA, Larsen CS, editors. Advances in dental anthropology. New York: Wiley-Liss. p 13–31. Turner CG II, Manabe Y, Hawkey DE. 2000. The Zhoukoudian Upper Cave dentition. Acta Anthropol Sin 19:253–268. von Koenigswald GHR. 1952. Evidence of a prehistoric AustralMelanesoid population in Malaya and Indonesia. Southwest J Anthropol 8:92–96. ‘‘Sundadonty’’ and the Population History of Southeast Asia: A Reply to Turner pooled close regional and chronological samples, and made further larger-scale comparisons using data compiled from major East/Southeast Asian and Paciﬁc groups. Mandibular molars were better preserved in a number of samples, and we could observe a sufﬁcient number of examples even in the case of traits, such as the sixth cusp, that are removed when dental attrition is severe. We agree with Turner that technology (especially foodprocessing technology) probably has an important effect on tooth size. However, contrary to Turner’s comments, our Figure 3 does not simply show that ‘‘teeth are generally ‘smaller’ in Northeast Asia than in Southeast Asia:’’ the actual picture is more complex. Certainly, the results in Figure 3 are difﬁcult to explain by culture alone. In his work, Turner has made laudable attempts to discuss the possible role of environmental and cultural practices on Mark J. Hudson1* and Hirofumi Matsumura2 1 Institute of History and Anthropology, University of Tsukuba, Tsukuba Science City, Ibaraki, Japan 2 Department of Anatomy, Sapporo Medical University, Sapporo, Hokkaido, Japan We thank Professor Turner for his interest in our research and his comments on our recent paper (Matsumura and Hudson, 2005). In his commentary, Turner raises a number of important issues, although several of his points go beyond the scope of our original article. In this reply, we will ﬁrst discuss the more speciﬁc methodological concerns raised by Turner, before moving on to a broader consideration of sundadonty and the population history of Southeast Asia. As noted by Turner, it is crucial to give sufﬁcient attention to dental wear when observing nonmetric dental traits and, indeed, when measuring teeth for metric analyses. This is a problem shared by all dental anthropologists, and every care was taken to select specimens and trait items least affected by wear. Due to difﬁculties in identifying the degree of shovel shape in the case of heavily worn incisors, a reduced sample size was unavoidable. In order to reduce the problem of lack of sufﬁcient sample size, we *Correspondence to: Mark J. Hudson, Institute of History and Anthropology, University of Tsukuba, Tsukuba Science City, Ibaraki 305-8571, Japan. E-mail: email@example.com Received 9 September 2005; accepted 12 October 2005. DOI 10.1002/ajpa.20381 Published online 27 January 2006 in Wiley InterScience (www.interscience.wiley.com). ‘‘SUNDADONTY’’ AND HISTORY OF SOUTHEAST ASIA selection for tooth size and shape (e.g., Turner, 1987, p. 310–316). Our understanding is that the thrust of Turner’s research has been the conclusion that selection plays at best only a minor role in dental nonmetric traits. We agree that metric analyses of the early Holocene Laos and Ban Kao samples place them with recent Southeast Asians, but as noted in our article, the typical Neolithic material culture at Ban Kao suggests that the site may have been produced by a farming population, even though remains of cultivated plants were not found. As also discussed in our article, the ‘‘early Holocene Laos’’ sample is probably a Mesolithic population with some later Neolithic skulls mixed in. Although the battery of dental traits and classiﬁcation methods in our study are not all identical with the plaques provided by Turner et al. (1991), the results of our cluster analysis in Figure 5 parallel the sundadonty and sinodonty classiﬁcations of Turner (1990). This is true even when Native Americans are included with similar Asian samples (Matsumura, 1995). The sundadont/sinodont model has proven to be an inﬂuential classiﬁcatory framework for the dental anthropology of East and Southeast Asia, and our article did not explicitly propose abandoning that framework as a whole. However, for modern human populations, we doubt whether the people of East and Southeast Asia can be sharply separated into two dental trait groups with the assumption of only minimal admixture. Therefore, in our article, we attempted to determine the existence of populations with characteristics intermediate between the sundadont and sinodont groups, using multidimensional scaling in addition to cluster analysis, since it is typically hard to exhibit such intermediate populations using only the latter type of analysis. The main difference between Turner’s work and our conclusions is in the interpretation of the process of the formation of the dental trait complex of modern Southeast Asians, whether through local evolution or through hybridization with East Asian immigrants. Our metric and nonmetric dental analyses concluded that the postNeolithic populations of Southeast Asia were formed through hybridization between pre-Neolithic ‘‘AusraloMelanesian’’ groups and immigrant farmers from East Asia. We argued that these results were not consistent with the local evolution hypothesis proposed by Turner (1990). Although Hanihara (1992) also proposed a similar local-evolution model, a recent ondotometric study by Hanihara and Ishida (2005, p. 292) found results similar to our own: ‘‘The present ﬁndings . . . do not support the division of East Asian populations into sinodonts and sundadonts proposed [by Turner] from analyses of nonmetric dental traits. . . The results of this study indicate that Chinese and Japanese populations are more like Southeast Asian populations, while the prehistoric Jomon show afﬁnities with Australian and Papuan populations.’’ POPULATION EXPANSION AND THE TWO-LAYER HYPOTHESIS As noted in our article, Turner’s work gives greater historical agency to a traditionally marginalized region (Southeast Asia); however, we do not assume that an immigration model in any way detracts from such agency. In our opinion, Turner’s present comments display an overly critical view of the concept of migration, a view that does not match recent trends in anthropological archaeology. While in the early 20th century the Neolithic migration model for Southeast Asia may indeed have been based on a ‘‘hodgepodge of inadequate, out-of-date, and sometimes 459 incorrectly interpreted osteological and archaeological evidence,’’ that is not the case today. While problems with the context of skeletal remains from early excavations continue (and are discussed in our article with respect to our samples), at present the mainstream opinion must surely be that actual population movement was associated with the expansion of agriculture from China into Southeast Asia. The evidence for this population movement was succinctly summarized by Bellwood (2005). One does not need to agree with all of Bellwood’s arguments to accept that the Neolithic migration model for Southeast Asia needs once again to be given serious consideration. The so-called ‘‘two-layer’’ hypothesis for Southeast Asia has clear similarities with the ‘‘dual structure’’ model proposed for the population history of the Japanese Islands by Hanihara (1991). The translation by Hanihara (1991) of ‘‘dual structure’’ is somewhat confusing, and the term ‘‘two-layer’’ is, in fact, closer to the original Japanese niju kozo. Both of these hypotheses model the expansion of East Asian (‘‘Mongoloid’’) agricultural populations into the peripheral regions of East Asia and their interactions with existing populations. Turner (1987, 1992) accepts that his data support immigration into the Japanese Islands during the Jomon-Yayoi transition, but he seems reluctant to accept a similar agricultural immigration into Southeast Asia. Turner writes, ‘‘One group in island Southeast Asia that the hypothetical Chinese farmers could not possibly have had much effect on are the Batak, a so-called ‘Negrito’ hunting and gathering forest people of the Philippines.’’ Apart from the fact that the term ‘‘Chinese’’ is wholly inappropriate here (Bellwood, 1995), it cannot be said that the Batak were not inﬂuenced by neighboring agricultural populations. To begin with, the Batak speak an Austronesian language, something which almost certainly reﬂects language shift, probably at an early stage of the agricultural colonization of the Philippines (Reid, 1987). Genetic studies of the Batak and other Philippine ‘‘Negritos’’ showed links with East Asians (Omoto, 1981, 1984, 1985). The position of the Batak in this respect may be rather similar to that of the Ainu. While mitochondrial DNA analyses by Horai et al. (1989, 1991) suggested that the Jomon people and their descendants, the Ainu, originated in Southeast Asia, other genetic comparisons found a strong Northeast Asian inﬂuence on the Ainu (Omoto, 1995; Omoto and Saitou, 1997; Oota et al., 1999). In terms of dental nonmetrics, Turner himself notes that the Ainu show signiﬁcant admixture. Although Jomon teeth are classiﬁed as sundadont, ‘‘Living Ainu teeth are rather like those of Japanese [i.e., sinodont], although the sundadont pattern can still be recognized’’ (Turner, 1987, p. 306). Because of this admixture, the Ainu were excluded from Turner (1987). Later, he claimed that ‘‘Ainu without Japanese admixture are also sundadonts’’ (Turner, 1992, p. 428), but no Ainu samples were analyzed in that paper, and as all the main Ainu skeletal collections were gathered in the late 19th and early 20th centuries, it is unlikely that they can be classiﬁed as ‘‘unadmixed.’’ Precise ﬁgures are difﬁcult, but Omoto (1973) estimated an admixture rate of about 40% for Ainu high-school students in the Hidaka district of Hokkaido, based on data from family registrations and interviews. Interestingly, this evidence for genetic and dental admixture runs parallel with quite clear cranial metric and nonmetric differences between the Ainu and the postYayoi Japanese (Dodo and Ishida, 1990; Hanihara, 1991). This raises the possibility that both the Ainu and the Batak display genetic and dental evidence for admixture, 460 M.J. HUDSON AND H. MATSUMURA while retaining an apparently less admixed craniofacial morphology. Although we have not yet seen the article by Turner and Eder (2006), in our opinion, these inﬂuences on the Batak provide support for the model of Neolithic agricultural expansions. Both the Ainu and the Batak (and other Southeast Asian ‘‘Negrito’’ groups) were heavily involved in trade and other interactions with surrounding farmers (Eder, 1987; Headland and Reid, 1989; Hudson, 1999a,b; Junker, 2002; Walker, 2001), yet the fact that the Ainu retained their own language until the 20th century suggests that forager-farmer interactions in Southeast Asia were very strong and unequal. JOMON/AINU LINKS The presence of Jomon and Ainu samples in the groups titled ‘‘Australians, Melanesians, and prehistoric Southeast Asians’’ in our Figures 1 and 2 does not mean that we are redeﬁning Southeast Asia to include those Japanese groups. Our article does not discuss the position of the Jomon/Ainu in any detail, but we cannot agree with Turner that ‘‘Only by ignoring the fact that the three Ainu-Jomon samples link with the prehistoric Southeast Asians can Matsumura and Hudson (2005) claim . . . modern Southeast Asians are a product of mixing with Neolithic farmers from the north.’’ In our metric analysis, the Jomon/Ainu cluster with Australo-Melanesians and prehistoric Southeast Asians, while in the nonmetric analysis, they group with modern Southeast Asians. While most archaeologists see only minor inﬂuences from Neolithic China on Jomon Japan, if sinodonty developed in East Asia before the start of the Jomon period (as Turner suggests in his comments), then it seems likely that sinodonty had already inﬂuenced Jomon teeth to some extent, presumably somewhere in late Paleolithic East Asia before the Jomon people reached Japan. While a number of studies through the 1980s and 1990s, including Turner’s own work, proposed links between the Jomon people and prehistoric Southeast Asians, from an archaeological perspective it has always been difﬁcult to argue that the Jomon populations arrived directly from Southeast Asia. The late Paleolithic and Jomon cultures of the Japanese Islands fall squarely into the Northeast Asian rather than Southeast Asian sphere. Turner here writes that, ‘‘The joining of prehistoric Southeast Asians with Jomonese and Ainu is to be expected, since they all possess sundadont morphology and share similar archaeological elements including shell mounds, dental transﬁgurement, and early pottery.’’ None of these archaeological elements, however, speciﬁcally link the two regions. Early Hoabinhian shell middens are found in Peninsular Malaysia, but the Hoabinhian toolkit is so different from the Jomon as to preclude a direct connection. Tooth ablation and ﬁling are known at Ban Kao in Thailand (Sangvichien, 1966) and at many Jomon sites (Harunari, 1986), but tooth ablation is found much earlier in north-central China, which may have been the center of origin of this custom (Han and Nakahashi, 1996) in east Eurasia. Pottery is known from late Pleistocene contexts in China and Japan (Yasuda, 2002), but only reaches Southeast Asia much later, with the spread of agriculture in the late Holocene (Bellwood, 1997). WHAT IS SUNDADONTY? The great strength of Turner’s work is that he has developed a broad synthetic model for the dental anthropology of East and Southeast Asia as well as Oceania and the Americas. Our results, however, do not support that model as regards Southeast Asia. Turner’s model is, of course, a typological classiﬁcation, and though we do not dispute the utility of such classiﬁcations for heuristic purposes, the reality of human diversity suggests much more complex patterns on the ground in eastern Asia. As already noted, Turner’s own work found that the Ainu display strong evidence for admixture. Other studies also found that many actual dental character states are more complicated than those originally described by Turner (Schwartz and Brauer, 1990; Manabe et al., 1992; Powell 1993; Bulbeck, 2000). If two dental nonmetric trait groups existed in East and Southeast Asia, then there must have been a region of admixture between those two groups. Turner’s own work has not identiﬁed such intermediate populations, but our article proposed that post-Neolithic Southeast Asians can be assigned to that intermediate position. Given the nature of our results, we accept that it may not have been appropriate to continue to use the term ‘‘sundadont.’’ We are aware that Turner (1992) and Hanihara (1992) used ‘‘proto-sundadont’’ to refer to an ‘‘evolutionary grade’’ between Australians and Southeast Asians. If, however, as our results suggest, Southeast Asian dental traits are a result of admixture with East Asians, then the term ‘‘proto-sundadont’’ would be inappropriate, since it suggests a prototype for an admixed form. One of the major difﬁculties with research on the population history of East and Southeast Asia has been the scarcity of well-preserved late Pleistocene human skeletal remains. From the perspective of cranial afﬁnities, late Neolithic to present-day Southeast Asians are morphologically considerably differentiated from Australians and Melanesians, as argued by Pietrusewsky (1992, 1994, 1999). However, skeletal and dental morphologies that can be linked with Australians or Melanesians are found in recently excavated late Pleistocene to early Holocene skeletons from Southeast Asia, such as the Moh Khiew Cave skeleton from southern Thailand, the Gua Gunung Runtuh specimen from Malaysia, and the Mai Da Due and Mai Da Nuoc specimens from northern Vietnam (Cuong, 1986; Matsumura and Zuraina, 1999; Matsumura and Pookajorn, 2005; Zuraina, 1994). The importance of these new discoveries is clear from the comment by Turner (1987, p. 319) that ‘‘It is, of course, possible that further sampling, particularly of older remains, may show the ancient presence of Australmelanesians in Southeast Asia. Assessment of this possibility will require excavations that provide Mesolithic and late Paleolithic skeletal remains.’’ Bulbeck (2000) discussed at length some of the interpretive problems resulting from the scarcity of pre-Neolithic materials in Turner’s Southeast Asian samples. Needless to say, further Hoabinhian skeletal remains will be of crucial importance in resolving the issue under debate here. Turner (1995, p. 229) saw the sundadont pattern as being ‘‘generalized and intermediate,’’ and our results certainly support the latter description. Turner (1992) proposed that these generalized/intermediate characteristics suggest that the sundadont region may have been the area of origin of modern humans. Our article, in contrast, argues that sundadonty is better interpreted as the result of admixture with post-Neolithic East Asians. The term ‘‘sundadont’’ could thus be retained, but to mean an admixed form. 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