Anthropological Science 108 (2), 169-181, 2000

Tooth Size of People in Wabag, Highlanders

and its Comparison with Pacific Peoples

Eisaku Kanazawa, Masanobu Matsuno, Hideyuki Sekiguchi,

Takanobu Suzuki, Takashi Satake, Kayoko Sasaki, and Yuriko Igarashi

Department of Anatomy, Nihon University School of Dentistry at Matsudo, Matsudo

(Submitted January 20, 2000; Review sent February 10, 2000; Accepted April 23, 2000)

•ôGH•ô Abstract•ôGS•ô Dental casts were recently collected from Highlanders in Kasi Village

of Wabag in of Papua New Guinea (PNG). Mean age of subjects

was 19.2 years ranged from 16 to 44. The mesiodistal and buccolingual diameters

of all upper and lower teeth (except third molars) were measured. Sex differences

of these diameters were relatively large in this population compared with other

Pacific populations. The results were compared with previous reports of Asian

Pacific populations including some Highland groups of PNG by cluster analysis

and multi-dimensional scaling from Mahalanobis' distances, Q-mode correlation

coefficients and Penrose's size distances. In the Mahalanobis' distances, Wabag

was clustered in the groups of Melanesians and Australian Aboriginals. In the

analysis of the distances transformed from Q-mode correlation coefficients,

Wabag was also clustered with these groups, but Fiji was clustered in Polynesians

and Micronesians. In the Penrose's size distances, Wabag teeth were smaller

than other Highlanders such as and Lufa, but were close to Polynesians.

This suggested that tooth size varied in a Highlander groups in PNG and that

there were marked polymorphism of Melanesians.

•ôGS•ô Keywords•ôNS•ô: Papua New Guinea, Highlanders, dental anthropology, tooth size

Introduction

Dental anthropological survey at Kasi village, Wabag in Enga Province of Papaua New

Guinea (PNG) was carried out by Nihon University Dental Survey Team in the summer

of 1997. Enga Province is one of the five separate provinces of the great Highlands area

of PNG, having 195,000 population. The province is made up of rugged mountains and

Corresponding author: Eisaku Kanazawa Department of Anatomy, Nihon University School of Dentistry at Matsudo Matsudo, Chiba, 271-8587 Japan TEL: +81-47-360-9317 FAX: +81-47-364-6295 Email: [email protected] 170 KanazawaE., MatsunoM., SekiguchiH., SuzukiT., Satake T., SasakiK., and IgarashiY. high valleys. People in this area are usually stockier and shorter than the coastal people, and are fragmented into small clans, but the -group covers most of the province and Engas belong to the largest single language-group in PNG. They traditionally cultivate sweet potatoes, bananas, sugar cane, greens and yams, although coffee is an important local industry. Wabag is the provincial capital of Enga arround which small villages are scattered in rural area. Kasi is one of those villages, 20km east of Wabag, where people engage mainly in agriculture of sweet potatos and coffee plantation. It has been pointed out that people in the Highland of PNG are direct descendants of Australoids in Western Melanesia and they have close relationship with Australian Aborigines on the basis of genetic studies (Howells, 1970; Bellwood, 1978). The dental anthropological study on the tooth size of PNG Highlanders, Goroka and Lufa in Eastern Highlands (Doran and Freedman, 1974) supported this hypothesis. Their tooth, referred as megadont, falls into the middle of the range of some Australian samples being larger than Island Melanesia samples (Harris and Bailit, 1987). Wabag locates about 250km west of Goroka and Lufa. People living in Wabag speak different language from Eastern Highlands. This study aims a description of tooth size of Wabag people and its comparison with Goroka and Lufa, and also with other Melanesians and related populations.

Materials and Methods Materials were dental plaster casts of permanent dentition collected from Kasi villagers in which 71 males (mean age 18.3 years) and 57 females (mean age 20.3 years) were included. The teeth on the right side of the maxillary and mandibular arches were measured except for third molars by digital calipers with the accuracy of 0.01mm. Any tooth with obvious dental abnormalities, excessive wear, caries, impression flaws, partial eruption, or fillings that obscured the proper placement of caliper beaks was excluded. When a tooth on the right side was not available according to these disturbances, corresponding tooth on the left side was measured. Tooth size measurements in Wabag were compared among 22 groups of different samples in the Pacific area (Figure 1). Data sources were mainly from our previous studies (Matsuno, 1997; Kanazawa and others, 1998) to avoid interobserver errors, but some other studies (Janzer, 1937; Bailit and others, 1968; Doran and Freedman, 1974; Townsend and Brown, 1979; Harris and Bailit, 1987; Yamada and others, 1988; Hanihara, 1990; Hamada and others, 1997) were also included in the comparison to have wide perspective of the dental size in the Pacific populations. Statistical methods applied in the present study were calculation of t-test, Mahalanobis' distances, transformed distances from Q-mode correlation coefficients (Hanihara, 1990), metric multi-dimensional scaling and cluster analysis. Computer analysis was performed in Macintosh personal computer with the use of JMP statistical package (SAS Institute Inc. Ver 3.1.6 for Macintosh). Tooth Size of Papua New Guinea Highlanders. 171

Figure 1 Geographical representation of the Highlanders in Papua New Guinea and other Pacific populations.

Results Table 1 showed mesiodistal and buccolmgual diameters m Wabag sample. Almost all the teeth had significant size differences between sexes except for mesiodistal diameters of upper lateral incisor and lower central and lateral incisors. Table 2 showed tooth size of the other Asian and Pacific samples used for comparison with Wabag sample. Mahalanobis' distances, transformed distances from Q-mode correlation coefficients and Penrose's size distances were computed between any pair of 22 Pacific samples based on the 28 tooth size parameters. The search for the affinity of the Oceanic populations on the basis of the male tooth size was attempted with these distances. Two kinds of dendrograms were drawn by the Ward method with the use of Mahalanobis' distances (Figure 2) and transformed distances from Q-mode correlation coefficients (Figure 3). Because the former distance includes the size factor in itself, major clusters express a large tooth group (Fiji to Goroka), a medium sized group (Samoa to Nasioi) and a small tooth group (Negrito to Hawaii). 172 KanazawaE., MatsunoM., SekiguchiH., SuzukiT., Satake T., SasakiK., and IgarashiY.

Wabag sample was grouped into a large tooth group which included mainly Melanesian and Australian samples with a few exception of Polynesian (Samoa) and Micronesian (Palau and Kiribati) samples. In a subcluster, however, Wabag was grouped with other PNG Highlanders. A cluster of a medium sized tooth group consists of South-east Asian and Polynesian populations with exception of three Melanesian populations (Nasioi, Kwaio and New Britain). Cluster analysis on the basis of transformed distances from Q-mode correlation coefficients neglects the size factor (Hanihara, 1990). Two major clusters were for

Table 1 Mesiodistaland buccolingualdiameters in Wabag (Papua New Guinea)

Significant sex differences of the means were denoted by asterisks, *: P<0 .05, **: P<0.01, ***: P<0.001. Tooth Size of Papua New Guinea Highlanders. 173 174 Kanazawa E., Matsuno M., Sekiguchi H., Suzuki T., Satake T., Sasaki K., and Igarashi Y.

Australo-Melanesians and for others. It was notable that PNG Highlanders including Wabag were clustered together with Australian Aborigines. Fiji, one of the major population in Melanesia, was not clustered in this group. Figures 4 and 5 showed two dimensional expression of mufti-dimensional scaling applied to Mahalanobis' distances and distances from Q-mode correlation coefficients based on

Figure 2 Dendrogram based on cluster analysis computed from Mahalanobis' distance using 28 crown diameters in 23 Pacific groups.

Figure 3 Dendrogram based on cluster analysis computed from Q-mode correlation coefficients using 28 crown diameters in 23 Pacific groups. Tooth Size of Papua New Guinea Highlanders. 175

Figure 4 Two dimensional expression of MDS applied to Mahalanobis' distances based on 28

crown diameters in 23 Pacific groups.

Symbols denote: •œ Melanesians, _??_ Australian, •› Polynesians, _??_ Micronesians,

_??_ Southeast Asians.

Figure 5 Two dimensional expression of MDS applied to distances transformed from Q-mode correlation coefficients based on 28 crown diameters in 23 Pacific groups. See Figure 4 for explanation for symbols. 176 KanazawaE., MatsunoM., SekiguchiH., SuzukiT., Satake T., SasakiK., and IgarashiY.

28 crown diameters in 22 populations, respectively. The distribution pattern of samples in Figure 4 was quite similar to the results of principal component analysis in which first component (x-axis) expressed general tooth size and second component (y-axis) did the shape factor showing the balance between large molar type and large incisor type. Melanesian samples were on the upper right side and Polynesians and Southeast Asians were contrarily on the lower left side. In Figure 5, Fijian samples which have relatively large teeth were scattered among Polynesian or Micronesian groups apart from Australo-Melanesians, because Q-mode correlation coefficients neglected a factor related to tooth size. Wabag was still closer to other Highland groups and Melanesians. Figure 6 showed linear expression of Penrose's size distances based on 28 crown diameters. Wabag's teeth were smaller than other PNG Highlanders, but a little larger than Micronesians and Australian Aborigines. Modern Fijians have the largest teeth among these samples.

Discussion The Highland native, sometimes referred to as "Papuan", is physically as well as linguistically distinct from his neighbors on the coast. The coastal Melanesian tends to be taller with a more gracile physiognomy than the Highlander. Typical individual in Highland area shows shorter stature, longer trunks, lower and longer cranial vaults, heavier browridges, a high frequency of convex noses, and larger dentition, which gives these relatively small people a prognathus appearance (Littlewood, 1972). Dental anthropological studies in this area has been so far carried out by following authors. Schamschula and others (1972) have associated molar tooth size and dental arch width with caries etiology in Sepik and Western Highlands. Boyd (1972) reported odontometric analysis on the basis of mesiodistal dimensions of Eastern Highland people (Kainantu). Barksdale (1972) studied non-metric dental characters also of the same people. Doran and Freedman (1974) also studied tooth size of Eastern Highlanders, Goroka and Lufa. These studies revealed that the Highland people had a megadont dentition similar in size to those aboriginal populations from Australia. When the dental dimension of Wabag was compared with other Highlanders, Goroka and Lufa (Doran and Freedman, 1974) were adopted, because these data consisted of complete set of mesiodistal and buccolingual diameters of maxillary and mandibular dentitions. Wabag's teeth were a little smaller than Goroka and Lufa, although the difference was small. They were altogether clustered in the same subcluster. Australian Aboriginal data cited in this study (Townsend and Brown, 1979) were also smaller than these Highlanders, but it is evident that there are considerable variation of tooth size among settlements of Australian Aboriginals (Smith and others, 1981). We compared 7 populations in Melanesia including 3 PNG Highlanders and 4 Eastern Islanders (New Britain, Nasioi, Kwaio, and Fiji). Their tooth sizes were larger than the grand mean of all the populations used in this study except for New Britain and Nasioi Tooth Size of Papua New Guinea Highlanders. 177

(Bougamville). Tooth size data from West Nakanai in New Britain (Turner and Swindler, 1978) and from Mussau Islands (Kirch and others, 1989) were not included in the present analysis because the former had some missing data in buccolingual diameters, and the latter had too small sample size. As far as their tooth sizes are concerned, it can be stated that West Nakanai and Mussau were relatively small to medium-sized for Melanesians just like Nasioi and Janzer's New Britain (Janzer, 1937). Their conditions probably reflect the well known marked polymorphism of Melanesians, and do not necessarily indicate gene flow from smaller-tooth migrants, such as Polynesians, whose routes to Polynesia from Indonesia would have had to pass through or nearby the Bismarck Archipelago, the group to which New Britain belongs (Turner and Swindler, 1978). Brace and Hinton (1981) also pointed out that tooth size on coastal New Guinea and island Melanesia, however, falls in between the large and the small to an extent that represents the ancestral contribution of each -- a situation that is nicely paralleled by the cultural and linguistic evidence for the mingling of Austronesian and non-Austronesian and New Guinea and non-New Guinea elements.

Figure 6 Linear expression of MDS applied to Penrose's size distances based on 28 crown diameters in 23 Pacific groups. See Figure 4 for explanation for symbols. 178 KanazawaE., MatsunoM., SekiguchiH., SuzukiT., Satake T., SasakiK., and IgarashiY.

Fijian teeth were the largest among the populations investigated, especially younger generation (Fiji S in Figure 6, Matsuno, 1997). This sample was collected in a secondary school in Suva, the capital of Fiji in 1995. As is well known, Fijians generally have large and stout figure of the body occasionally with excess of fat due to high nutritional western food in these recent years. This situation might affect the change of tooth size. In addition, tooth size so far measured in Melanesia was from highly worn teeth because of their traditional nature of attrition. However, this sample in Fiji was from young people showing hardly slight attrition. A widely accepted opinion that Australian Aborigines' teeth are the largest among living peoples in the world should be corrected. The reason why Brace and Hinton (1981) did not include Fijians into large-toothed group in Melanesia in their study on Oceanic tooth size variation may be due to extremely small sample size from there. Tooth size varies with time, even in a single population without any change of gene flow. Tooth size enlargement, or positive secular trend of dentition, has been observed in present day populations due to the change of nutritional status and life styles (earn and others, 1968; Corruccini and Lee, 1984; Kieser and others, 1984). The typical example is recent size enlargement in industrial countries (Garn and others, 1968; Corruccini and Lee, 1984) and also in developing countries such as Fiji (Kanazawa, 1997). However, Kieser (1990) suggested that the current information was inadequate and speculative on the causation of tooth size enlargement in recent populations. Although there is controversy about the causation of positive odontometric trends, tooth size enlargement in a few decades implies that the data obtained in the present study might not reflect the original tooth size of people in Oceania when they migrated into the islands some hundreds years ago. Two kinds of dendrograms drawn in the present study based on Mahalanobis' distance and Q-mode correlaion enables us to explain dichotomous interpretation of population affinities. In the former analysis, two major clusters represents a large toothed group including PNG Highlanders, Fijians, Australian Aborigines, Micronesians and some other large toothed Polynesians and a small to medium sized group including Negritos, Javanese, Polynesians and West Melanesians (Nasioi). In the latter analysis being free from size components, contrarily, all the PNG group including Nasioi, Australian Aborigines constructed one major cluster and Polynesians, Micronesians, Southeast Asians and Fijians did another major cluster. This Q-mode based clustering seems to be reasonable from a point that the Sahul-Pacific people are clustered together, although Melanesians, Polynesians, Southeast Asians and Fijians were mixed in the subclusters in another major cluster. Shape proportionality has repeatedly been shown to be a more pertinent measure of group relationship than size (Spielman, 1973; Penrose, 1954). Tooth size of Micronesians which is medium sized in the present comparison of Penrose's size distance might indicate that there was a Melanesian influence to Micronesia. This can be supported by Brace and Hinton (1981) that the slightly larger tooth size of the Micronesians might indicate that they have absorbed something from the Australo- Melanesians to their immediate south, although their craniofacial proportions firmly ally Tooth Sizeof Papua New GuineaHighlanders. 179

them with the Jomon-Pacific cluster. Archaeological and linguistic evidence also support this hypothesis (Intoh, 1997; Shutler and Marck, 1975). Turner (1990) proposed two major dental groups in Mongoloid populations, that is, Sundadonty and Sinodonty, based on non-metric dental characters. In addition to them, Proto-Sundadont or Sahul-Pacific has also been proposed to represent the dentition of Australian Aboriginals, New Guineans and some Melanesian populations (Hanihara, 1992; Scott and Turner, 1997). The Sahul-Pacific group has relatively large teeth and consistent proportion of mesiodistal and buccolingual diameters and also front teeth and back teeth with a few exception of Fijians. Similarity of tooth size and tooth proprotions in PNG Highlanders were also demonstrated by multivariate analysis in this study.

Acknowledgment We are indebted to Mr. Ikunas Kipkap, coordinator of this research in Kasi region, for his arrangement of dental examination for villagers. Thanks are also to Mr. Anthony Kandomain, Tsikiro Community School, for his assistance to trafic services and to Drs. Shuichi Hinokuchi, Ikkei Hashimoto, Akio Shizushima, students of Nihon University School of Dentistry at Matsudo for their assistance in dental survey. Special thanks are to Yuichi Satoh, Adventure and Research Club of Keio University for his guide to PNG and Kasi Village. This research was supported by Grant-in-Aide for Scientific Research (C) from Ministry of Education, Science and Culture, Japan (No. 09640838) in 1997 and 1998.

REFERENCES Bailit H.L., DeWitt S.J., and Leigh R.A. (1968) The size and morphology of the Nasioi dentition. American Journal of Physical Anthropology, vol. 28, pp. 271-288. Barksdale J.T. (1972) A descriptive and comparative investigation of dental morphology. Appendix III. In Littlewood R.A. eds., "Physical Anthropology of the Eastern Highlands of New Guinea", University of Washington Press, Seattle and London. Bellwood P. (1978) Man's Conquest of the Pacific. The Prehistry of South east Asia and Oceania. Oxford University Press, London. Boyd R.C. (1972) An odontometric and observational assessment of the dentition. Appendix IV. In Littlewood R.A. ed., "Physical Anthropology of the Eastern Highlands of New Guinea", University of Washington Press, Seattle and London. Brace C.L. and Hinton R.J. (1981) Oceanic tooth-size variation as a reflection of biological and cultural mixing. Current Anthropology, vol. 22, pp. 549-569. Corruccini R.S. and Lee G.T.R. (1984) Occlusal variation in Chinese immigrants to the United Kingdom and their offspring. Archives in Oral Biology, vol. 29, pp. 779-782. Doran G.A, and Freedman L. (1974) Metrical features of the dentition of populations from Goroka and Lufa, Papua New Guinea. Human Biology, vol. 46, pp. 583-594. Garn S.M., Lewis A.B., and Walenga A. (1968) Evidence for a secular trend in tooth size over two generations. Journal of Dental Research, vol. 47, p. 503. Hamada R., Kondo S., and Wakatsuki, E. (1997) Odontometric analysis of Filipino 180 KanazawaE., MatsunoM., SekiguchiH., SuzukiT., Satake T., SasakiK., and IgarashiY.

dentition, Journal of Showa University Dental Society, vol. 17, pp. 197-207. Hanihara T. (1990) Affinities of the Philippine Negritos with Japanese and the Pacific populations based on dental measurements: The basic populations in East Asia, I. Journal of the Anthropological Society of Nippon, vol. 98, pp. 13-27. Hanihara T. (1992) Negritos, Australian Aborigines, and the "Proto-Sundadont" dental pattern: the basic population in East Asia, V. American Journal of Physical Anthropology, vol. 88, pp. 183496. Harris E.F. and Bailit H.L. (1987) Odontometric comparisons among Solomon Islanders and other Oceanic peoples. In Friedlaender J.S. ed., "The Solomon Islands project: A long term study of health, human biology and culture change". Oxford University Press, Cambridge, pp. 215-264. Howells W.W. (1970) Physical variation and history in Melanesia and Australia. American Journal of Physical Anthropology, vol. 45, pp. 641-650. Intoh M. (1997) Human dispersals into Micronesia. Anthropological Science, vol. 105, pp. 15-28. Janzer O. (1937) Die Zahne der Neu-Pommern. Vierteljhrsschr. Zahnhlk. vol. 43, pp. 289-319 (in German). Kanazawa E. (1997) Tooth size change in recent generations of Fiji. Proceedings for VIII Pacific Science Congress, The University of the South Pacific. Suva, Fiji, p. 175. Kanazawa E., Matsuno M., Nakabayashi T., Igarashi Y., and Nagai A. (1998) Tooth size of living peoples in western and eastern Micronesian populations. Anthropological Science, vol. 106, pp. 199-208. Kieser J.A. (1990) Human Adult Odontometrics. Cambridge University Press, Cambridge, pp. 58-60. Kieser J.A., Groeneveld H.T., and Cameron N. (1984) Evidence for a secular trend in the Negro dentition. Annals of Human Biology, vol. 14, pp. 517-532. Kirch P.V., Swindler D.R., and Turner II C.G. (1989) Human skeletal and dental remains from Lapita sites (1600-500 B.C.) in the Mussau Islands, Melanesia. American Journal of Physical Anthropology, vol. 79, pp. 63-76. Littlewood R.A. (1972) Physical Anthropology of the Eastern Highlands of New Guinea. University of Washington Press, Seattle and London. Matsuno M. (1997) Dental anthropological study on tooth size in Fiji, Western Samoa and Kiribati. Nihon University Journal of Oral Science, vol. 23, pp. 33-52 (in Japanese). Penrose L.S. (1954) Distance, size and shape. Annals of Eugenics, vol. 18, pp. 337-343. Scott G.R, and Turner II C.G. (1997) The anthropology of modern human teeth. Cambridge University Press, Cambridge. Schamschula R.G., Barmes D.E., and Adkins B.L. (1972) Caries aetiology in Papua New Guinea. Association of tooth size and dental arch width. Australian Dental Journal, vol. 17, pp. 188-195. Shutler R.J. and Marck J.C. (1975) On the dispersal of the Austronesian horticulturalists. Archaeology and Physical Anthropology in Oceania, vol. 10, pp. 81-113. Tooth Size of Papua New Guinea Highlanders. 181

Smith P., Brown T., and Wood W.B. (1981) Tooth size and morphology in a recent Australian aboriginal population from Broadbeach, South East Queensland. American Journal of Physical Anthropology, vol. 55, pp. 423-432. Spielman R.S. (1973) Do the natives all look alike? Size and shape components of anthropometric differences among Yanomama Indian villages. American Naturalist, vol. 107, pp. 694-708. Townsend G.C. and Brown T. (1979) Tooth size characteristics of Australian Aborigines. Occasional paper in Human Biology, vol. 1, pp. 17-38. Turner II C.G. (1990) Major features of Sundadonty and Sinodonty, including suggestions about East Asian microevolution, population history, and late Pleistocene relationships with Australian aboriginals. American Journal of Physical Anthropology, vol. 82, pp. 295-317. Turner II C.G. and Swindler D.R. (1978) The dentition of New Britain West Nakanai Melanesians, VIII. Peopling of the Pacific. American Journal of Physical Anthropology, vol. 49, pp. 361-372. Yamada H., Kawamoto K., Sakai T., and Katayama K. (1988) Inter-island variation in tooth size of the Cook islanders, and their biological affinities with other Oceanic people, Journal of the Anthropological Society of Nippon, vol. 96, pp. 435-448.

Handling editor: Ishida Hajime