Sinodonty and Sundadonty

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Distribution of sinodonts and sundadonts in Asia, shown by yellow and red. Also shown are australoids, indicated by A, and negritos, indicated by N.[1]

Sinodonty and Sundadonty are two patterns of features widely found in the dentitions of different populations in East Asia. These two patterns were identified by anthropologist Christy G. Turner II as being within the greater "Mongoloid dental complex".[2] Sundadonty is regarded as having a more generalised, Australoid morphology and having a longer ancestry than its offspring, Sinodonty.

The combining forms Sino- and Sunda- refer to China and Sundaland, respectively, while -dont refers to teeth.

Mongoloid Dental Complex[edit]

"In contrast to the broad Mongoloid Dental Complex," Turner defined the Sinodont and Sundadont dental complexes.[3] Hanihara defined the Mongoloid Dental Complex in 1966. In 1984, Turner separated the Mongoloid Dental Complex into the Sinodont and Sundadont dental complexes.[4]

Description[edit]

Male Sinodont Mongoloid (Japanese) and female Sinodont Mongoloid (Kalmyk)
Male Sundadont Mongoloid (Filipino) and female Sundadont Mongoloid (Indonesian)

Turner found the Sundadont pattern in the skeletal remains of Jōmon people of Japan, and in living populations of Taiwanese aborigines, Filipinos, Indonesians, Borneans, and Malaysians.

By contrast, he found the Sinodont pattern in the Han Chinese, in the inhabitants of Mongolia and eastern Siberia, in the Native Americans, and in the Yayoi people of Japan.

Sinodonty is a particular pattern of teeth characterized by the following features:

  • The upper first incisors and upper second incisors are shovel-shaped, and they are "not aligned with the other teeth".[5]
  • The upper first premolar has one root (whereas the upper first premolar in Caucasians normally has two roots), and the lower first molar in Sinodonts has three roots (3RM1) whereas it has two roots in Caucasoid teeth.[5][3]

Applicability[edit]

In the 1990s, Turner's dental morphological traits were frequently mentioned as one of three new tools for studying origins and migrations of human populations. The other two were linguistic methods such as Joseph Greenberg's mass comparison of vocabulary or Johanna Nichols's statistical study of language typology and its evolution, and genetic studies pioneered by Cavalli-Sforza.[original research?]

Today, the largest number of references to Turner's work are from discussions of the origin of Paleo-Amerindians and modern Native Americans, including the Kennewick Man controversy. Turner found that the dental remains of both ancient and modern Amerindians are more similar to each other than they are to dental complexes from other continents, but that the Sinodont patterns of the Paleo-Amerindians identify their ancestral homeland as north-east Asia. Some later studies have questioned this and found Sundadont features in some American peoples.

For example, in 1996, Rebecca Haydenblit of the Hominid Evolutionary Biology Research Group at Cambridge University did a study on the dentition of four pre-Columbian Mesoamerican populations and compared their data to "other Mongoloid populations".[6] She found that "Tlatilco", "Cuicuilco", "Monte Albán" and "Cholula" populations followed an overall "Sundadont" dental pattern "characteristic of Southeast Asia" rather than a "Sinodont" dental pattern "characteristic of Northeast Asia".[6]

Data tables[edit]

Data sources for the mesiodistal crown diameters of permanent teeth in the 24 Asian populations
Population Period Provenance N Author
Sundadont Negrito Modern Aeta, Philippine 21 Hanihara (1990)
Filipino Modern Philippine (Unspecified ethnicity) 20 Cruz (1971)
Filipino Modern Manila, Philippine (Tagalog) 100 Potter et al. (1981)
Filipino Modern Manila, Philippine (Tagalog) 110 Hamada, Kondo & Wakatsuki (1997)
Thai Modern Bangkok, Thailand 110 Matsumura (1994)
Indonesians Modern Java, Celebes, Sumatra, Kalimantan Islands 47 Matsumura (1995)
Okinawans Modern Okinawa, Japan 25 Hanihara (1989)
Hokkaido Ainu Modern Hokkaido, Japan 61 Matsumura (1994)
Jomon Neolithic Whole Japan 711 Matsumura (1994)
Tanegashima Yayoi Aeneolithic Tanegashima Island, Japan 60 Matsumura (1994)
Sinodont Northern Kyushu Yayoi Aeneolithic Fukuoka and Yamaguchi prefs., Japan 212 Matsumura (1994)
Kofun Prothohistoric Kanto, Kinki, Northern Kyushu, Japan 287 Matsumura (1994)
Kamakura Early Medieval Kanto, Japan 364 Matsumura (1994)
Edo Early Modern Kanto, Japan 254 Matsumura (1994)
Modern Japanese Modern Kanto, Japan (Showa Univ.) 105 Hamada, Kondo & Wakatsuki (1997)
Koreans Modern Seoul, Korea 120 Cho (1973)
Ugra Mongolians Early Modern Ulan Bator, Mongol 132 Matsumura (1995)
Taiwan Chinese Modern Kaohsiung, Taiwan 103 Liao (1984)
Northern Chinese Modern Northern China 149 Matsumura (1994)
Beijing Chinese Modern Beijing, China 25 Miura et al. (1991)
Paiwan Modern Taiwan 95 Sasaki (1982)
Rukai Modern Taiwan 79 Nagayama (1984)
Bunun Modern Taiwan 89 Kudo (1985)
Atayal Modern Taiwan 182 Takei (1990)
Source: Hamada, Kondo & Wakatsuki (1997)[7]
Frequencies of the Crown Characters Composing the "Mongoloid Dental Complex" (♂+♀, in %)
Population Shovel-Shape Protostylid Defl. Wrinkle 6th Cusp 7th Cusp
di1 di2 dm2 dm2 dm2 dm2
Japanese 76.6 (124) 93.3 (163) 44.7 (152) 71.6 (201) 36.9 (92) 73.7 (156)
Pima Indian 61.6 (78) 64.3 (98) 89.0 (118) 84.3 (115) 36.8 (117) 72.9 (118)
Eskimo 50.0 (16) 60.0 (5) 67.3 (52) 67.9 (53) 37.7 (53) 79.4 (63)
Am. White 0.0 (20) 0.0 (24) 14.5 (55) 13.0 (54) 7.3 (55) 40.7 (54)
Am. Negro 10.0 (10) 15.0 (22) 17.0 (47) 19.1 (47) 14.0 (50) 46.8 (47)
Ainu 50.0 (4) 66.7 (9) 45.5 (22) 70.0 (20) 23.8 (21) 71.4 (21)
Figures in parenthesis show numbers of individuals observed.
Source: Hanihara (1970)[8]
Sundadonty and sinodonty
Variant Sundadont Mean %
frequency (range)
Sinodont Mean %
frequency (range)
Upper 1st incisor shoveling (grades 3–6) 31 (0–65) 71 (53–92)
Upper 1st incisor double-shoveling (grades 2–6) 23 (0-60) 56 (24–100)
One-rooted upper 1st pre-molars 71 (50–90) 79 (61–97)
Upper 1st molar enamel extension (grades 2–3) 26 (0–50) 50 (18–62)
Peg/reduced/absent upper 3rd molars 16 (0–27/51) 32 (16–46)
Deflecting wrinkle in lower 1st molars (grades 2–3) 26 (0–58) 44 (0–86)
Three-rooted lower 1st molars 9 (0–19) 25 (14–41)
Four-cusped lower 2nd molars 31 (6–64) 16 (4–27)
Means rounded to nearest %
Source: Turner II (2002) via Hillson (1996)[9]

See also[edit]

References[edit]

  1. ^ Howells, William W. (1997). Getting Here: the story of human evolution. ISBN 0-929590-16-3
  2. ^ G. Richard Scott, Christy G. Turner, (2000). The Anthropology of Modern Human Teeth: Dental Morphology and Its Variation in Recent Human Populations. Cambridge University Press. ISBN 0521784530
  3. ^ a b Scott, R.G. (1997). Encyclopedia of Human Biology. Second Edition. Volume 3. Pages 175-190. Retrieved December 14, 2016, from link.
  4. ^ Díaz, E. et al. (2014). Frequency and variability of dental morphology in deciduous and permanent dentition of a Nasa indigenous group in the municipality of Morales, Cauca, Colombia. In Colombia Médica, 45(1). Pages 15–24. Retrieved December 14, 2016, from link.
  5. ^ a b Kimura, R. et al. (2009). A Common Variation in EDAR Is a Genetic Determinant of Shovel-Shaped Incisors. In American Journal of Human Genetics, 85(4). Page 528. Retrieved December 24, 2016, from link.
  6. ^ a b Haydenblit, R. (1996), Dental variation among four prehispanic Mexican populations. American Journal of Physical Anthropology, 100: 225–246. doi: 10.1002/(SICI)1096-8644(199606)100:2<225::AID-AJPA5>3.0.CO;2-W
  7. ^ Hamada, R., Kondo, S. & Wakatsuki, E. (1997). Odontometrical Analysis of Filipino Dentition. In The Journal of Showa University Dental Society, 17. Page 198. Retrieved December 27, 2016, from link.
  8. ^ Hanihara, K. (1970). Mongoloid Dental Complex in the Deciduous Dentition with Special Reference to the Dentition of the Ainu. In Journal of the Anthropological Society of Nippon, 78(1). Page 6. Retrieved December 26, 2016, from link.
  9. ^ Hillson, S. (2002). Dental Anthropology. United Kingdom: Cambridge University Press. Retrieved December 14, 2016 from link.

External links[edit]