169-181, 2000 Tooth Size of People in Wabag, Papua New Guinea

Anthropological Science 108 (2), 169-181, 2000 Tooth Size of People in Wabag, Papua New Guinea 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 Enga Province 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 Goroka 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 Enga language-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

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