deciduous dental morphology of the prehistoric jomon people of japan: comparison of nonmetric...

AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 97:lOl-111 (1995)

Deciduous Dental Morphology of the Prehistoric Jomon People of Japan: Comparison of Nonmetric Characters

YOSHIKAZU KITAGAWA, YOSHITAKA MANABE, JOICHI OYAMADA, AND ATSUSHI ROKU'IXNDA Department of Oral Anatomy, Nagasaki University School of Dentistry, Nagasaki, 852 Japan

KEY WORDS Nonmetric trait

Jomonese, Dental anthropology, Deciduous teeth,

ABSTRACT Morphological variations of the deciduous dentition are as useful as those of the permanent dentition for determining the biological affinities of human populations. This paper provides material on morphological variations of deciduous teeth of the prehistoric Japanese population from the Late and the Latest Jomon Period (ca. 2000-ca. 300 B.c.).

The expression of nonmetric traits of the deciduous teeth in the Jomon sample shows a closer affinity with modern Japanese and Native American samples than with American White, Asiatic Indian, and African samples. However, the frequency of shoveling in deciduous upper incisors in the Jomon sample is lower than those in modern Japanese and Native American samples. The Jomon sample also expresses a much higher frequency of cusp 6 in deciduous lower second molars than seen in modern Japanese, Ainu, and Native American samples. The frequency in the Jomon sample is equal to that in the Australian Aboriginal sample, which shows cusp 6 most frequently among the samples compared.

A somewhat low incidence of incisor shoveling in the Jomon sample was also reported in the permanent dentition (Turner [19761 Science 193:911-913, [19791 Am. J. Phys. Anthropol. 51:619-635, [19871 Am. J. Phys. Anthropol. 73:305-321, [19901 Am. J . Phys. Anthropol. 82:295-317; T. Hanihara [1992] Am. J. Phys. Anthropol. 88:163-182,88:183-196). However, the frequency of cusp 6 in the Jomon sample shows no significant difference from those of Northeast Asian or Native American samples in the permanent dentition (Turner [1987] Am. J . Phys. Anthropol. 73:305-321; T. Hanihara [1992] Am. J. Phys. Anthropol. 88:163-182, 88:183-196). Evidently, some nonmetric traits express an inter-group difference only in the deciduous dentition. 0 1995 Wiley-Liss, Inc.

Comparisons of nonmetric dental features have been valuable in making assessments of the affinities of human populations. Such comparisons, however, have tended to con- centrate upon the permanent dentition. The deciduous dentition should also be studied in investigating population affinities, because it may evolve independently of the permanent dentition and therefore yield different and additional information. For example, Brabant (1967) presents reasons for believing that the morphological evolution

of the deciduous dentition has been less rapid than that of the permanent dentition. Wolpoff (1979) showed that during the Wiirm glaciation, the size of deciduous teeth and 'permanent anterior teeth increased, while that of permanent posterior teeth re-

Received June 28,1993; accepted December 28,1994, Address reprint requests to Yoshikazu Kitagawa, Department

of Oral Anatomy, School of Dentistry, Nagasaki University, Nagasaki, 852 Japan.

0 1995 WILEY-LISS, INC.

102 Y. KITAGAWA ET AL.

duced in Europe. Yet apart from the series of studies by K. Hanihara (1954, 1955, 1956a,b, 1957,1963,1965,1966,1967,1968, 1970,1976), few investigations have utilized nonmetric features of the deciduous dentition in assessing population affinities (Sci- ulli, 1977, 1990; Kaul and Prakash, 1981; Lukacs and Walimbe, 1984; Grine, 1986, 1990). Moreover, the potentials of these studies are limited, partially by the lack of a consensus concerning the classification and interpretation of some nonmetric traits.

From studies of the morphology of the permanent dentition in the prehistoric Japa- nese population from the Late and the Lat- est Jomon Period (ca. 2000-ca. 300 B.c.) (Turner, 1976,1979,1987, 1989; Brace and Nagai, 1982; Matsumura, 1989; T. Hani- hara, 1992a,b), there has emerged a consensus that the permanent dentition of the Jomon people shows little similarity to that of modern Japanese, but much similarity to that of the Ainu in either metric or nonmetric characteristics. Turner (1987) summa- rized his extensive studies on dental nonmetric traits and presented a hypothesis concerning the population history of the East Asians in the Late Pleistocene and Ho- locene Ages. In his paper, Turner classified the prehistoric Jomon people in the “Sunda- dont” group (Southeast Asians, Polynesians, and Micronesians), while he assigned modern Japanese to the “Sinodont” group (Northeast Asians and Native Americans) according to his dichotomy of Mongoloid populations based on dental nonmetric traits.

In this paper, we provide information about nonmetric traits of the deciduous dentition in the prehistoric Jomon sample to compare the results with those of other ap- propriate samples. We also present a pre- liminary comparison with the results of the studies on the permanent dentition (Turner, 1979, 1987, 1990; T. Hanihara 1992a-c) to figure out whether the deciduous dentition of the Jomon is also of the “Sundadont” type seen in the permanent dentition.

MATERIALS AND METHODS The sample consists of the deciduous

teeth from the remains of 61 infants and children unearthed from four shell mounds

46”

0 200 400

KILOMETERS u

Sea of Japan

130’E Tsukumo

Yoshiko Kamayama Inariyama

D Pacific Oceun

00

30” I I

Fig. 1. Map of Japan showing site location. The Yoshiko, Kameyarna, and Inariyama sites are located closely, within 40 km.

belonging to the Late and the Latest Jomon Period (ca. 2 0 0 h a . 300 B.C.): the Tsukumo site is in Okayama Prefecture (western Ja- pan), and the Yoshiko, Kameyama, and In- ariyama sites are in Aichi Prefecture (central Japan); see Figure 1 for their locations. The sample is housed in the Laboratory of Physical Anthropology, Kyoto University. A slight regional variation in the Jomon populations was found from the studies on both cranial (Yamaguchi, 1982) and dental (Mat- sumura, 1989) measurements between western and central Japan. However, since the regional variation falls within the range of that existing among modern Japanese (Yamaguchi, 1982), and since sub-dividing the dental sample by region results in inad- equately small samples, the present analysis of the Jomon deciduous dental morphology is based on pooled samples from the four sites. We also did not try to divide male and female samples in counting trait expressions because deciding the sex of infants and children is impractical unless skeletal material is well preserved.

We recorded the following nonmetric characters: shoveling in the deciduous upper first and second incisors and in decidu-

JOMON DECIDUOUS TEETH 103 TABLE 1. Nonmetric characters of deciduous teeth in the prehistoric Jomon sample

Trait Expression (Reference) Number of individuals (a) Shoveling (di') N 0 1 2 3 (K. Hanihara, 1961) 24 9(37.5) N25.0) 9(37.5) O(O.0) Shoveling (di2) N 0 1 2 3 (K. Hanihara, 1961) 18 l(5.6) N44.4) 9(50.0) O(O.0) Shoveling (dc') N 0 1 2

Shoveling (dc,) N 0 1 2 3 (K. Hanihara, 1961) 34 13(38.2) 18(52.9) 3(8.8) O(O.0)

Cusp number (dm') N 2 3H 3M 4- & 4

Paramolar tubercle (dml) N Absent Welt cusp

Hypocone development (dm') N 3 & A 3 & B 4- 4

(K. Hanihara, 1961) 26 14(53.8) ll(42.3) l(3.8)

(K. Hanihara, 1961, 1963) 39 3(7.7) l(2.6) 25(64.1) lO(25.6)

(Jmgensen, 1956) 34 31(91.2) l(2.9) 2(5.9)

(K. Hanihara, 1961) 42 O(O.0) O(O.0) 7(16.7) 35(83.3) Carabelli trait (dm') N 0 1 2 & 3 4825 6 & 7 (K. Hanihara, 1961, 1963) 40 6(15.0) 17(42.5) 12(30.0) 3(7.5) 2(5.0) Metaconule (drn,) N Absent Present (K. Hanihara, 1956b) 26 7(26.9) lg(73.1) Enamel extension (dm2) N 0 1 2 3 (Turner, 1979) 38 32(84.2) 6(15.8) O(O.0) O(O.0)

Delta-shaped crown (dm,) N Delta Other shape (K. Hanihara, 1961) 52 2(3.8) 50(96.2) Protostylid (dm,) N 0 & 1 2 & 3 4 & 5 6

Deflecting wrinkle (dm,) N Absent Present (K. Hanihara et al., 1964) 44 N(36.4) 28(63.6)

Cusp 6 (dm,) N Absent Trace Semi Marked (Suzuki and Sakai, 1973) 51 lg(37.3) 3 6 9 ) 7(13.7) 22(43.1)

(K. Hanihara, 1961) 44 14(31.8) g(20.5) 13(29.5) 8(18.2) Distolingual root (dm,) N Absent Present (Turner, 1971)

(K. Hanihara, 1961, 1963) 40 22155.0) 1X37.5) 3(7.5) O(O.0)

Cusp 7 (dm,) N 0 1 2 3

26 26(100.0) O(O.0)

ous upper and lower canines; cusp number and paramolar tubercles in deciduous upper first molars; development of hypocones, the Carabelli trait, metaconules, and enamel extensions in deciduous upper second molars, delta-shaped crowns in deciduous lower first molars, and protostylids, deflecting wrinkles, cusp 6, cusp 7, and distolingual roots in deciduous lower seconds molars. We recorded most of them using the standard plaques of K. Hanihara (1961) for deciduous dental traits. The classification methods that we used to record variations are refer- enced later in the text and listed in Table 1.

We employed the individual count method (Scott, 1977, 1980) to enumerate the non-

metric traits in this investigation. This method counts the strongest expression of a given trait on either the right or left side of the jaw, and if one side is missing, the de- gree of expression on the side present is scored. Thus, each variant was counted per individual, not per tooth.

In deciduous teeth, comparisons of frequencies of nonmetric traits are limited by the lack of investigations and compatible standards for use in recording nonmetric traits. In Tables 2-4, we make comparisons of the frequencies of the nonmetric traits between the Jomon and other population samples. In preparing the tables, we chose comparative population samples that were

104 Y. KITAGAWA ET AL

TABLE 2. Shoveling frequencies in deciduous anterior teeth'

Population

Prehistoric Jomon Japanese Ainu Pima Indian Prehistoric Ohio Indian Eskimo Australian Aborigines American White Jat Chalcolithic Inamgaon American Black South African Black Kalahari San

dil (grades 2 & 3)

37.5 (24) 76.6 (124) 50.0 (4) 61.5 (78) 79.2 (24) 50.0 (16) 76.3 (38) 0.0 (20) 4.4 (68)

15.4 (39) 10.0 (10) 0.0 (20) 4.3 (47)

di2 (grades 2 & 3)

50.0 (18) 93.3 (163) 66.7 (9) 64.3 (98) 92.3 (26) 60.0 (5) -

0.0 (24) 0.8 (119)

30.8 (26) 9.5 (21) 0.0 (27)

11.5 (52)

dc' (grade 2)

3.8 (26) 8.6 (197) - -

88.0 (25) - -

0.0 (52) - -

0.0 (51) 0.0 (28) 0.0 (65)

dc, (grades 2 & 3)

8.8 (34) 5.5 (199) - -

96.7 (30) - -

2.0 (49)

2.1 (47) 0.0 (37) 1.3 (75)

- -

Reference

This study K. Hanihara (1963, 1965) K. Hanihara (1970) K. Hanihara (1968) Sciulli (1990) K. Hanihara (1968) K. Hanihara (1976) K. Hanihara (1963, 1965) Kaul and Prakash (1981) Lukacs and Walimbe (1984) K. Hanihara (1963, 1965) Grine (1986) Grine (1990)

'In percentages, with sample size in parenthesis.

TABLE 3. Nonmetric trait frequencies in deciduous upper molars'

Cusp Paramolar Hypocone Carabelli Enamel number tubercle development trait Metaconule extension

grade 4- & 4 present grade 4 grades P 7 present grades 2 & 3 Pooulation (dml) (dm') (dm2) (dm2) (dm2) (dm2) Reference

Prehistoric Jomon

Japanese

Ainu

Rma Indian

Prehistoric

Eskimo

Australian

Danes

Medieval Danes

Ohio Indian

Aborigines

American White

Jat

Chalcolithic Inamgaon

American Black

South African

25.6 (39)

20.1 (184)

-

-

22.2 (27)

-

-

-

-

0.0 (55)

-

11.4 (44)

20.0 (50)

31.4 (35)

83.3 (42)

70.7 (191)

-

82.4 (?)

100.0 (24)

74.5 (?)

-

-

-

73.7 (57)

52.9 (314)

65.3 (46)

90.2 (51)

94.3 (35)

12.5 (40)

11.9 (185)

16.0 (25)

0.0 (118)

10.3 (29)

0.0 (54)

21.0 (105)

87.2 (641)

83.6 (55)

35.7 (56)

11.8 (306)

8.8 (45)

11.8 (51)

3.1 (32)

73.1 (26)

41.8 (?)

-

47.0 (?)

33.3 (27)

29.1 (?)

- ~ 5 . 0 (?)

-

3.5 (?)

-

-

9.5 (?I

8.6 (35)

This study

K. Hanihara

K. Hanihara

K. Hanihara

Sciulli (1990)

(1963, 1967)

(1970)

(1967, 1968)

K. Hanihara (1967, 1968)

K. Hanihara (1976)

Jgrgensen (1956)

Jwgensen (1956)

K. Hanihara (1963, 1967)

Kaul and Prakash (1981)

Lukacs and Walimbe (1984)

K. Hanihara (1963, 1967)

Grine (1986) Black

Grine (1990) Kalahari San 56.2 (73) 5.5 (91) 87.9 (99) 8.4 (95) 5.2 (77) -

*In percentages, with sample size in parenthesis.

widely distributed geographically and traits that were recorded by using the same classification method or one that could be readily applied to our classification systems. The references of these samples are noted in Ta- bles 2-4.

We compared the frequencies of six traits (shoveling in deciduous upper first incisors, development of hypocones and the Carabelli trait in deciduous upper second molars, protostylids, cusp 6 , and cusp 7 in deciduous lower second molars) in ten samples (Japa-

JOMON DECIDUOUS TEETH 105

TABLE 4. Nonmetric trait frequencies in deciduous lower molars'

Deflecting Distolingual Delta-shaped Protostylid wrinkle Cusp 6 cusp 7 root

crown grades 2-6 present trace-marked mades 1 3 oresent

Prehistoric Jomon

Japanese

Ainu

Pima Indian

Prehistoric

Eskimo

Polynesian

Ohio Indian

Australian

Danes

Medieval Danes

American White

Jat

Aborigines

Chalcolithic Inamgaon

American Black

South African Black

45.0 (40)

44.7 (152)

45.5 (22)

89.0 (118)

-

67.3 (52)

-

36.8 (76)

-

-

14.5 (55)

0.0 (322)

1.6 (61)

17.0 (47)

16.2 (37)

63.6 (44)

71.6 (201)

70.0 (20)

84.3 (115)

74.2 (31)

67.9 (53)

-

74.6 (71)

-

-

13.0 (54)

44.0 (275)

-

19.1 (47)

-

-

62.7 (51)

36.9 (92)

23.8 (21)

36.8 (117)

41.2 (34)

37.7 (53)

54.4 (103)

68.1 (72)

2.8 (213)

2.6 (38)

7.3 (55)

0.9 (322)

18.0 (61)

14.0 (50)

18.4 (38)

68.2 (44)

73.7 (156)

71.4 (21)

72.9 (118)

-

79.4 (63)

72.8 (103)

63.3 (90)

- 5.0 (?) -

40.7 (54)

0.0 (322)

1.7 (60)

46.8 (47)

53.8 (39)

This study

K. Hanihara

K. Hanihara

K. Hanihara

Sciulli (1990)

K. Hanihara (1968)

Suzuki and Sakai (1973)

(1968)

(1970)

(1968)

K. HaNhara (1976)

Jorgensen (1956)

Jmgensen (1956)

K. Hanihara (1968)

Kaul and Prakash (1981)

Lukacs and Walimbe (1984)

K. Hanihara (1968)

Grine (1986)

33.3 (69) 40.8 (76) Grine (1990) 6.5 (93)

'In percentages, with sample size in parenthesis

nese, Pima Indian, Eskimo, American White, Jat of north-western India, the Late Chalcolithic inhabitants of the Inamgaon site in western India, American Black, South African Black, Kalahari San, and the present Jomon sample) from the data in Ta- bles 2-4 by a multivariate statistical technique. We used a correspondence analysis (Lebart et al., 1984; Greenacre, 1984) in the comparison. Correspondence analysis, a variant of principal component analysis, is a multidimensional graphical technique used to show which rows or columns of a frequency table have similar patterns of counts. The major advantage of correspondence analysis is that rows and columns are represented simultaneously with reference to the same axes in multidimensional space. This permits the visual interpretation of differences between populations and of the rel-

ative participation of each nonmetric trait in the dispersion. In the field of physical anthropology, correspondence analysis has been applied to gene frequency data (Green- acre and Degos, 1977), frequency data of dental caries and elements contained in dental enamel (Schneider, 1986), and frequency data of dental nonmetric traits (Sci- ulli, 1990), for example.

RESULTS AND DISCUSSION Table 1 presents the results of the analy-

sis of nonmetric traits in the Jomon sample. Comparisons with other population samples are presented in Table 2 (shoveling of deciduous anterior teeth), Table 3 (nonmetric traits of deciduous upper molars), and Table 4 (nonmetric traits of deciduous lower molars). A description of the deciduous dental characteristics in the Jomon sample accom-


panies the results of the comparisons with other samples. Differences noted as significant in the comparisons were found to be significant using a chi-square test or Fish- er’s exact probability test (P < 0.05).

Shoveling of deciduous anterior teeth In the Jomon sample, no incisors exhib-

ited the strongest grade of expression of shoveling. The incidence of shoveling was 37.5% in this sample. Japanese, Native American, and Australian Aboriginal samples exhibited higher frequencies of shoveling of the deciduous upper incisors than other samples. The deciduous upper first and second incisors of the Jomon manifested significantly lower frequencies of shoveling than most of these samples. The Ainu sample also evinced slightly lower incidences of shoveling than these samples, though the sample size is small. The frequencies of shoveling in the deciduous upper and lower canines were very low among all the samples except the prehistoric Ohio Indian sample, which was the only sample that differed significantly from the others in this trait.

Nonmetric traits of deciduous upper molars

In the deciduous upper first molars, the Jomon sample exhibited three cusps most frequently. In most of the three-cusped deciduous upper first molars, the third cusp was a metacone (grade 3M). The incidence of four-cusped deciduous upper first molars in the Jomon was 25.6%, which was similar to those in the modern Japanese, prehistoric Ohio Indian, and American Black samples.

The incidence of paramolar tubercles (welt + cusp) in deciduous upper first molars in the Jomon was 8.8%. The presence of paramolar tubercles in the deciduous upper first molars was rare among the comparative samples, and no significant difference between the Jamon and other samples was found.

In the Jomon sample of deciduous upper second molars, the hypocone was usually large and well developed (grade 4). No three- cusped deciduous upper second molars with a small hypocone cuspule (grades 3 + A and 3 + B) were found in this sample. The Jomon sample exhibited a moderate to high

incidence of the hypocone by comparison with the other samples.

Carabelli cusps of varying sizes (grade 4-7) were present in only 12.5% of the Jomon sample. Pit and groove expressions of this variable were most frequent. The Jomon sample frequency resembled those of the Japanese, Ainu, prehistoric Ohio Indian, Jat, and American Black samples, showing a significantly higher incidence than those in the Pima Indian and Eskimo samples. The Carabelli cusp occurred more frequently in the Danish and American White samples than in other samples. However, the extremely high frequencies found in two Danish samples (Jwgensen, 1956) might have been caused by our inappropriate ad- aptation of these data to K. Hanihara’s classification.

The kind of metaconule that we recorded in this study was a small tubercle located on the buccal portion of the oblique crista, separated from the metacone by a distinct groove. The Jomon sample showed a somewhat high incidence (73.1%) of this trait. Next to the Jomon, the Japanese and Native American samples showed higher frequencies than other samples. However, since no detailed description on the expression of this trait is found in the references of the comparative samples, the results of the comparison must be interpreted with caution.

All the deciduous upper second molars in the Jomon sample showed either straight or slightly curved buccal cervical lines, so that no deciduous upper second molar exhibited distinct enamel extension (i.e., exceeding Turner’s grade 2). Enamel extension seems a rare variant in deciduous upper molars. There have been few studies concerning enamel extension in deciduous molars.

Nonmetric traits of deciduous lower molars

Occlusal outlines of deciduous lower first molars sometimes exhibited triangular shapes in contrast to ordinary rectangular shapes (K. Hanihara, 1961). This type of crown was characterized by an elongated buccolingual crown diameter in the distal end and a developed cusp in the middle of the distal margin, and could be easily distin- guished from other forms. The incidence of


such delta-shaped crowns in the deciduous lower first molars of the Jomon was 3.9%. Among the comparative samples, the prehistoric Ohio Indian expressed a relatively high incidence.

The protostylids of the deciduous lower second molars in the Jomon sample exhibited zero expression (grade 0 and 1) most frequently and divergence of the buccal groove (grade 2 and 3) next most frequently. This trait was expressed at an extremely high frequency in the Native American samples and at moderately high frequencies in the Jomon, Japanese, Ainu, and Australian Aboriginal samples. The frequency in the Jomon sample was 45.0%, significantly lower than those in the Pima Indian and Eskimo samples.

Deflecting wrinkles were recorded following K. Hanihara et al. (1964). They described several variations on this variant, but all of them are assigned to two catego- ries: present (any deflection of the occlusal ridge of a metaconid), or absent (Table 1). The incidence of this trait in the Jomon was 63.6%. This trait expressed high frequencies in the Japanese, Ainu, Native American, and Australian Aboriginal samples. The Jomon exhibited slightly lower incidence than these samples, but the difference was significant only with the Pima Indian sample.

The classification method used to record cusp 6 variation is based on Suzuki and Sa- kai (1973). We classified relative size of cusp 6 by measuring the length of cusp 6 and entoconid with calipers. The length of cusp 6 is defined as a linear distance between two points where buccal and lingual occlusal grooves that bound cusp 6 run over a distal marginal ridge. The length of entoconid is also defined in the same way, as a linear distance between two points where mesial and distal occlusal grooves that bound entoconid run over a lingual marginal ridge. The incidence of this trait in the Jomon was 62.7% and most of the cusp 6s in the Jomon sample had a marked expression (that is, their length was more than half that of the entoconid). This trait was expressed at an extremely high frequency in the Jomon, Australian Aboriginal, and Polynesian samples and at moderately high frequencies in

the Japanese and Native American samples. The Ainu manifested a slightly lower frequency of cusp 6 than those of Japanese and Native American samples. As already described by K. Hanihara and

Minamidate (1965), cusp 7 variations in the deciduous lower second molars are somewhat different from those in the permanent molars. A weak groove on the lingual surface of the metaconid (grade 1) occurs frequently in the deciduous lower second molars. The pooled incidence of cusp 7 (from grades 1 to 3) in the Jomon was 68.2%. This trait was expressed at extremely high frequencies among the Jomon, Japanese, Ainu, Native American, Polynesian, and Austra- lian Aboriginal samples. Next to these samples, the African and American White samples evinced higher frequencies of cusp 7 than the two samples from India. We did not include the comparative data recorded by Jergensen’s (1956) classification in Table 4, since we suspected that these frequencies might have been calculated without consid- ering the presence of a faint expression of this trait.

An accessory distolingual root in the deciduous lower second molars was absent in twenty-six individuals (0%) of the Jomon sample. The prehistoric Ohio Indian sample expressed a higher incidence of this trait than the other samples.

Ordination of samples by correspondence analysis

Detailed population affinities of the Jomon people with Ainu, Polynesians, Southeast Asians and Australian Aborigi- nals have been investigated in studies of the permanent dentition and skull (Turner, 1979, 1987, 1990; T. Hanihara, 1992a-c, 1993a,b). Because there are not enough comparative data on traits of the deciduous dentition, we cannot address this issue in detail. K. Hanihara (1976) used deciduous dental nonmetric traits and a multivariate statistical method to estimate modern population affinities. Here, we present a similar ordination using somewhat different traits, samples, and statistical methods. Figure 2 depicts the graphical results of our correspondence analysis using six deciduous dental traits in ten human populations. In this

108

Japanese

Protostylid (dm2) Pima Indian

0

r

Y. KITAGAWA ET AL.

0 Chalcolithic Inamgaon I

ha= 0.0398 (14.8%)

0 American White

Jat

analysis, first and second axes are deter- mined in much the same way as that of principal component analysis. A first axis through the origin is defined as that axis along which the variation is a maximum. The second axis is that one, among all axes orthogonal to the first one, along which the variation is a maximum. This two-dimen- sional display accounts for 78.1% of the total variations in the original data matrix. The data points for American Whites and Ja t fall on the right of the figure, while Pima Indian, Eskimo, Japanese, and the Jomon samples lie to the left and the African samples and the Late Chalcolithic Inamgaon sample from western India falls in the middle. Among the different variants, the Inamgaon sample showed intermediate frequencies between the American White and East Asian samples (Lukacs and Walimbe, 1984). The position of the Inamgaon sample reflects the frequencies of these traits. The Jomon sample appears in the range of the Japanese and Native American populations, but is slightly separated from them.

In Figure 2, the directions of populations and nonmetric traits from the origin have meaning, and indicate the relative participation of each nonmetric trait in the dispersion of the populations. In the morphologic characteristics that we employed in this analysis, the Carabelli trait in the deciduous upper second molars was designated to the far upper right of Figure 2, thus being associated with the American White and Jat. The traits of shoveling in the deciduous upper first incisors and protostylids in the deciduous lower second molars appear to the left of the figure, associated with the Japa- nese, Pima Indian, and Eskimo. Well-developed hypocones in the deciduous upper second molars, being arranged in the central portion of the figure, are associated with the African populations. Cusps 6 and 7 in the deciduous lower second molars are associated with the Jomon sample.

This comparison distinguishes three clus- ters-the Jomon, Japanese, and Native American cluster; African and American Black cluster; and modern Asiatic Indian


and American White cluster, as did that of K. Hanihara (1976), besides indicating that the Jomon sample is somewhat different from Japanese and Native American samples.

Comparison with results from studies of the permanent dentition

In the permanent dentition, Turner (1983, 1987, 1989, 1990) identified eight key nonmetric traits that characterize the “Sunda- dont” (Southeast Asians, Pacific peoples, Ainu, and the Jomon) and “Sinodont” (Eastl Northeast Asian and Native American) populations: shoveling and double-shoveling in the upper central incisors; root number in the upper first premolars; enamel extension in the upper first molars; pegs, reduction, and congenital absence of the upper third molars; deflecting wrinkles and root number in lower first molars; and cusp number of lower second molars. In the deciduous dentition, the traits that agree with these traits are shoveling and double-shoveling in the deciduous upper first incisors, enamel extension in the deciduous upper second molars, and deflecting wrinkle and root number in the deciduous lower second molars. But we did not record double-shoveling, since the expression of labial marginal ridges in deciduous incisors was too weak to record this trait correctly.

In the present analysis, the Jomon sample showed a significantly lower frequency of shoveling in deciduous upper incisors than most of the Japanese and Native American samples. The Ainu evinced an intermediate incidence of shoveling between the Jomon and these samples, but the incidence should be interpreted with caution since the sample size is small. The frequency of a deflecting wrinkle in the deciduous lower second molars was also lower than those in the Japa- nese, Ainu, and Native American samples, but only the Pima Indian sample showed a significant difference from the Jomon. Enamel extensions in the deciduous upper second molars and distolingual roots in the deciduous lower second molars have not been adequately studied in the deciduous dentition of the “Sinodont” samples, so we could not compare these traits between the

Jomon sample and these others. In compar- ing our findings with those of Turner’s studies (1979, 1987, 1989, 1990) of the permanent dentition, we found that the deciduous dentition of the Jomon is also “Sundadont” in terms of the expression of incisor shoveling.

Besides the incisor shoveling, the Jomon sample expressed an extremely high incidence of the metaconule in the deciduous upper second molars and of cusp 6 in the deciduous lower second molars compared with the Japanese and Native American samples. Because the metaconule that we recorded in this study was not recorded in Turner’s studies (1976, 1979, 1987, 1989, 1990), we could not compare the results with his studies of the permanent dentition. The frequency of cusp 6 in the Jomon sample was significantly higher than in most of the Jap- anese, Ainu, and Native American samples, and almost equal to that in the Australian Aboriginals and Polynesians. Turner (1990) pointed out similarity in seven out of eight above-mentioned key traits between the Australian Aborigines and the “Sundadont” populations. Yet, T. Hanihara (1992b) re- vealed that there are several differences in expression of dental nonmetric traits between the Australian Aborigines and the “Sundadont” populations. The five characters which distinguish Australian Aborigi- nes from the “Sundadont” populations are weak shoveling in the upper central incisors, hypocones in the upper second molars, cusp 6 and deflecting wrinkles in the lower first molars, and hypoconulids in the lower second molars (T. Hanihara, 1992b). The dental pattern of Australian Aborigines is termed “Proto-Sundadont” by T. Hanihara (1992b), applying Turner’s terminology. In the expression of cusp 6 in the deciduous lower second molars, the Jomon and Polyne- sians are “Proto-Sundadont.”

However, in the permanent first molar, the incidence of cusp 6 showed no significant difference between the Jomon and the other “Sinodont” populations (Turner, 1987; T. Hanihara 1992a,b). In comparison with the “Sinodont” populations, the difference in expression of cusp 6 was observed only in the deciduous dentition. Furthermore, the Ainu,


often regarded as having biological affinities to the Jomon people, exhibited lower incidences of cusp 6 both in the deciduous and permanent dentition than the Jomon, and even lower than the “Sinodont” populations (T. Hanihara, 1992a,b).

Differences observed in cusp 6 expression between the deciduous and permanent den- titions of the Jomon, and between the Jomon and Ainu, could not be interpreted in the present analysis. There have been too few comparative studies to elucidate whether the differences between the “Sinodont” and the “Sundadont” or “Proto-Sundadont” populations in the permanent dentition are also found in the deciduous dentition. Although the present analysis is based on a small sample size and limited comparative samples, we hope that our finding that some nonmetric traits exhibit an inter-group difference only in the deciduous dentition will promote study of the deciduous dentition in investigating biological relationships among human populations.

ACKNOWLEDGMENTS The authors are deeply indebted to Dr.

Kazumichi Katayama and Dr. Hidemi Ishida, Laboratory of Physical Anthropol- ogy, Faculty of Science, Kyoto University, for their permission to investigate the Jomon samples. Financial support for this study was partially provided by a Grant-in- Aid from the Japan Ministry of Education, Science, and Culture 03740423.

LITERATURE CITED Brabant H (1967) Comparison of the characteristics and

anomalies of the deciduous and the permanent dentition. J. Dent. Res. 463397-902.

Brace CL, and Nagai M (1982) Japanese tooth size: past and present. Am. J. Phys. Anthropol. 59:399411.

Greenacre MJ (1984) Theory and Applications of Corre- spondence Analysis. New York: Academic Press.

Greenacre MJ, and Degos L (1977) Correspondence analysis of HLA gene frequency data from 124 population samples. Am. J . Hum. Genet. 29:60-75.

Grine FE (1986) Anthropological aspects of the deciduous teeth of South African blacks. In R Singer and JK Lundy (eds.): Variation, Culture and Evolution in African Populations. Johannesburg: Witwatersrand University Press, pp. 47-83.

Grine FE (1990) Deciduous dental features of Kalahari San: comparison of non-metrical traits. In GH Sper- ber (ed.): From Apes to Angels: Essays in Anthropol- ogy in Honor of Phillip V. Tobias. New York: Wiley- Liss, pp. 153-169.

Hanihara K (1954) Studies on the deciduous dentition of the Japanese and the Japanese-American hybrids. I. Deciduous incisors. J . Anthropol. SOC. Nippon 63:168- 185.

Hanihara K (1955) Studies on the deciduous dentition of the Japanese and the Japanese-American hybrids. 11. Deciduous canines. J. Anthropol. SOC. Nippon 64: 63-82.

Hanihara K (1956a) Studies on the deciduous dentition of the Japanese and the Japanese-American hybrids. 111. Deciduous lower molars. J. Anthropol. SOC. Nip- pon 64:95-116.

Hanihara K (195613) Studies on the deciduous dentition of the Japanese and the Japanese-American hybrids. N . Deciduous upper molars. J. Anthropol. SOC. Nip- pon 65:67-87.

Hanihara K (1957) Studies on the deciduous dentition of the Japanese and the Japanese-American hybrids. V. General conclusion. J. Anthropol. SOC. Nippon 65:

Hanihara K (1961) Criteria for classification of crown characters of the human deciduous dentition. J . An- thropol. Soc. Nippon 69:2745.

Hanihara K (1963) Crown characters of the deciduous dentition of the Japanese-American hybrids. In DR Brothwell (ed.): Dental Anthropology. London: Perga- mon Press, pp. 105-124.

Hanihara K (1965) Some crown characters of the deciduous incisor and canines in Japanese-American hybrids. J . Anthropol. SOC. Nippon 72:135-145.

Hanihara K (1966) Mongoloid dental complex in the deciduous dentition. J . Anthropol. Soc. Nippon 74: 61-71.

Hanihara K (1967) Racial characteristics in the dentition. J. Dent. Res. 46:92%926.

Hanihara K (1968) Morphological pattern of the deciduous dentition in the Japanese-American hybrids. J . Anthropol. SOC. Nippon 76:114-121.

Hanihara K (1970) Mongoloid dental complex in the deciduous dentition, with special reference to the dentition of Ainu. J. Anthropol. SOC. Nippon 783-17.

Hanihara K (1976) Statistical and comparative studies of the Australian Aboriginal dentition. Bull. Univ. Mus. Univ. Tokyo 11:l-57.

Hanihara K, Kuwashima T, and Sakao N (1964) The deflecting wrinkle on the lower molars in recent man. J. Anthropol. SOC. Nippon 72:1-8.

Hanihara K, and Minamidate T (1965) Tuberculurn acces- soriurn mediak internurn in the human deciduous lower second molars. J. Anthropol. Soc. Nippon. 733-19.

Hanihara T (1992a) Dental and cranial affinities among populations of East Asia and the Pacific: The basic populations in East Asia, N . Am. J . Phys. Anthropol. 88:163-182.

Hanihara T (199213) Negritos, Australian Aborigines, and the ”proto-sundadont” dental pattern: The basic populations in East Asia, V. Am. J . Phys. Anthropol.

Hanihara T (1992~) Biological relationships among Southeast Asians, Jomonese, and the Pacific Popula- tions as viewed from dental characters: The basic populations in East Asia, X. J. Anthropol. SOC. Nippon 100:53-67.

Hanihara T (1993a) Craniofacial features of Southeast

151-164.

88: 183-1 96.


Asians and Jomonese: A reconsideration of their microevolution since the Late Pleistocene. Anthropol. Sci. 101:25-46.

Hanihara T (199313) Population Prehistory of East Asia and the Pacific as viewed from craniofacial morphology: the basic populations in East Asia, VII. Am. J. Phys. Anthropol. 91:173-187.

J~rgensen KD (1956) The deciduous dentition, a descriptive and comparative anatomical study. Acta Odontol. Scand. 14:l-202.

Kaul V, and Prakash S (1981) Morphological features of Jat dentition. Am. J . Phys. Anthropol. 54:123-127.

Lebert L, Morineau A, and Warwick KM (1984) Multi- variate Descriptive Statistical Analysis. New York Wiley.

Lukacs JR, and Walimbe SR (1984) Deciduous dental morphology and biological affinities of a Late Chal- colithic skeletal series from Western India. Am. J. Phys. Anthropol. 65:23-30.

Matsumura H (1989) Geographic variation of dental measurements in the Jomon population. J. Anthropol. SOC. Nippon 97:493512.

Schneider KN (1986) Dental caries, enamel composition, and subsistence among prehistoric Amerindians of Ohio. Am. J. Phys. Anthropol. 71r95-102.

Sciulli PW (1977) A descriptive and comparative study of the deciduous dentition of prehistoric Ohio Valley Amerindians. Am. J. Phys. Anthropol. 47:71-80.

Sciulli PW (1990) Deciduous dentition of a Late Archaic population of Ohio. Hum. Biol. 62:221-245.

Scott GR (1977) Classification sex dimorphism, associa- tion, and population variation of the canine distal accessory ridge. Hum. Biol. 49:453-469.

Scott GR (1980) Population variation of Carabelli’s trait. Hum. Biol. 52:63-78.

Suzuki M, and Sakai T (1973) Occlusal surface pattern of the lower molars and the second deciduous molar among the living Polynesians. Am. J. Phys. Anthro- pol. 39:305-316.

Turner CG I1 (1971) Three-rooted mandibular first permanent molars and the question of American Indian origins. Am. J. Phys. Anthropol. 34:229-242.

Turner CG I1 (1976) Dental evidence on the origins of the Ainu and Japanese. Science 193r911-913.

Turner CG I1 (1979) Dental anthropological indications of agriculture among the Jomon people of central Ja- pan. X. Peopling of the Pacific. Am. J. Phys. Anthro- pol. 51:619-635.

Turner CG I1 (1983) Sinodonty and sundadonty: a dental anthropological view of Mongoloid microevolution, origin and dispersal into the Pacific Basin, Siberia and the Americas. In RS Vasilievsky (ed.): Late Pleis- tocene and Early Holocene Cultural Connections of Asia and America. Novosibirsk USSR Academy of Science, Siberian Branch, pp. 72-76 (in Russian).

Turner CG I1 (1987) Late Pleistocene and Holocene population history of East Asia based on dental variation. Am. J. Phys. Anthropol. 73:305321.

Turner CG 11 (1989) Teeth and prehistory in Asia. Sci. Am. 263:7&77.

Turner CG I1 (1990) Major features of Sundadonty and Sinodonty, including suggestions about East Asian microevolution, population history, and Late Pleis- tocene relationships with Australian Aboriginals. Am. J . Phys. Anthropol. 82:295-317.

Yamaguchi B (1982) A review of the osteological characteristics of the Jomon population in Prehistoric Japan. J. Anthropol. SOC. Nippon 90:77-90.

Wolpoff MH (1979) The Krapina dental remains. Am. J. Phys. Anthropol. 50:67-114.

deciduous dental morphology of the prehistoric jomon people of japan: comparison of nonmetric...

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