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Efficacy of cranial versus dental measurements for separating human populations.

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AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 57~123-127(1982)
Efficacy of Cranial Versus Dental Measurements for
Separating Human Populations
DEAN FALK AND ROBERT CORRUCCINI
Department of Anatomy and the Caribbean Primate Research Center,
University of Puerto Rico, Medical Sciences Campus, G.P.O. Box 5067, Sun
J u a n Puerto Rico 00936 (D.F.), and Department of Anthropology, Southern
Illinois University, Carbondale, Illinois 62901 (R.C.)
KEY WORDS
Craniometry, Race, Odontometry, Analysis of variance
ABSTRACT
Cranial and dental measurements were taken on 100 skulls, consisting of 20 specimens each, representing five different human populations. In
addition to traditional cranial and dental measurements, sets of nonstandard
basicranial and cervical dental measurements were collected. The data were subjected to univariate and multivariate analyses to determine what kinds of data
best sort human populations. Both univariate and multivariate analyses indicate
that traditional and nontraditional cranial measurements separate major human
groups better than do dental measurements, with traditional cranial
measurements providing the best sorting criteria. The cervical dental
measurements proved to be better sorters of human groups than the traditional
maximum dental measurements for univariate, but not for multivariate, analyses.
Thus, when utilizing univariate techniques, osteologists can increase sample sizes
of teeth by collecting cervical data.
Traditional cranial measurements have been
used to sort human populations for over one
hundred years (e.g., Broca, 1874; Hrdlicka,
1907; De Quatrefages and Hamy, 1882). Recently, Howells (1969) addressed the problem
of how one determines which cranial measurements best distinguish human populations
and suggested that multivariate techniques be
applied to identify measurements that are optimal for analyzing human variation. Dental
measurements have also traditionally been
used to sort human populations (Hanihara,
1977; Harris and Nweeia, 1980; Sofaer, et al.,
1971). There are few if any studies of the
relative efficacy of cranial versus dental
measurements. The purpose of this paper is to
conduct such a study using both univariate
and multivariate methods of analysis.
Maximum mesial-distal and buccal-lingual
dental measurements have traditionally been
used in racial and paleontological comparisons,
although attrition severely affects maximum
dental measurements (Wolpoff, 1971). Since
tooth wear is severe enough in some groups to
destroy discriminative power, cervical measurements taken at the cemento-enamel junction may be preferable to traditional maximum
0002-948318215701-0123$02.00c 1982 ALAN R LISS, INC.
measurements for intraspecific (Black, 1978,
1979)and interspecific (Corruccini, 1977)comparisons. Therefore, in addition to comparing
cranial with dental measurements, this study
tests the relative sorting efficacy of traditional
and nontraditional dental measurements. Similarly, although Howells’ (1969) osteometric
study shows that certain traditional cranial
measurements do distinguish between human
populations, he notes that “the base of the
skull (has been) generally neglected and not
properly covered” (1969:455).A third purpose
of the present study is to test the relative
merits of some measurements on the inferior
base of the skull and traditional cranial measurements for distinguishing human
populations.
MATERIALS AND METHODS
Cranial and dental measurements were
taken on one hundred skulls housed at the
United States National Museum of Natural
History. Five major human populations were
each represented by ten skulls from adult feReceivpd April 16. 19R1: accepted September 14. 19R1
124
D. FALK AND R. CORRUCCINI
males and ten skulls from adult males. The five
groups include representatives from Terry Collection blacks and whites (collectedin the U.S.
during the second quarter of the twentieth century); Eskimos from Point Hope, Alaska
(1929); Mongolians from Urga (1912); and
Amerindians from Jersey County, Illinois
(1945). Terry Collection blacks are estimated
as admixed 20-30% with whites (Corruccini,
1974; Angel, personal communication). The
Eskimo, Mongolian, and Amerindian samples
are more homogeneous than the Terry Collection blacks and whites. A cautionary note is
that any of these three homogeneous samples
could represent breeding isolates and therefore
may not be typical of their larger parent racial
groups.
Four sets of measurements were taken (from
the left sides of skulls when unilateral) by one
of us (D.F.) over a period of several weeks.
Set 1
The six traditional cranial measurements include maximum length, maximum breadth,
face height (nasion-prosthion), nasal breadth,
bizygomatic breadth and basicranial distance
(nasion-basion).
Set 2
Unlike the traditional skull measurements,
these six small measurements do not span
more than one bone (i.e., they represent small,
localized traits), some are innovative, and all
are located near the basioccipital area: basioccipital length (basion-hormion), basioccipital
breadth (minimum breadth of basiocciput),
posterior nares maximum breadth, maximum
carotid diameter (once thought a correlate of
cranial capacity), foramen magnum breadth
and posterolateral jugular-anteromedial
foramen lacerum distance. These traits are
located on the portion of skull that is often preserved relatively intact or undeformed in archeological remains, whereas the entire skull is
rarely preserved as an intact unit.
Set 3
The six traditional dental measurements include maximum length upper canine, maximum breadth upper canine, maximum length
upper third premolar, maximum breadth upper third premolar, maximum length upper
first molar, and maximum breadth upper first
molar. These particular teeth were selected in
order to sample representatives of different
dental fields and therefore to maximize re-
trieval of independent information. In each
case, the first (polar) tooth was selected because it is the relatively least variable and
most highly intercorrelated tooth within its
field (Dahlberg, 1945; Henderson, 1975).
Set 4
Maximum cervical length and breadth measurements were taken at the cemento-enamel
junction of each of the polar teeth measured in
Set 3 (cervical measurements are figured in
Corruccini, 1977).
In one group (Eskimos) delayed repeat measurements were taken for the entire sample.
Measurement error averaged 1.3% of the
smaller reading for craniometrics, and 3.6% for
odontometrics.
Statistics
Basic descriptive statistics and univariate
(F-tests)and multivariate (Wilks’lambda) variance ratios were computed from the data
(Table I). Six measurements were selected for
each of the four sets because this is an appropriate number of measurements for a statistically powerful multivariate analysis in conjunction with sample sizes of n = 20. Wilks’
lambda was used as the criterion for judging
intergroup difference in the multivariate analysis. Wilks’ lambda is the ratio of the determinants of the within-group and of the amonggroup plus within-group variance-covariance
matrices. The smaller this ratio is, the more effective the separation of the ellipsoids of
samples in the multivariate space (Anderson,
1958). Conversely, larger values of the standard univariate variance ratios (F-ratios) indicate more between-group and less withingroup variance. These variance ratios constitute meaningfully comparable criteria of discriminability, as each analysis includes the
same number of variables and specimens.
RESULTS
The mean univariate variance ratio for six
traditional cranial measurements is 7.49, that
for the set of nontraditional cranial measurements is 5.40 (Table 1).The maximum dental
measurements have an average univariate
variance ratio of 2.67, while the nontraditional
cervical dental measurements yield a mean
ratio of 3.28 (seeTable 1).Thus univariate analysis indicates that both traditional and nontraditional cranial measurements separate
racial groups better than do dental measurements, with traditional cranial measurements
providing the best sorting criteria.
7.34
8.18
6.53
8.89
10.09
11.15
5.59
7.76
4.73
8.20
7.91
10.65
Maximum dental measurements
canine length
canine breadth
P' length
P' breadth
M' length
M' breadth
Cervical dental measurements
canine length
canine breadth
P' length
P' breadth
M ' length
M' breadth
(0.54)
(0.72)
(0.39)
(0.58)
(0.39)
(0.64)
(0.47)
(0.71)
(0.77)
(0.56)
10.821
(0.57)
(2.94)
(2.19)
(2.18)
(0.71)
(1.65)
(2.16)
'Each human population is represented by 20 skulls.
*Not statistically significant at p = 0.05. See Lext tor discussion.
29.77
21.96
28.83
7.18
31.66
35.89
(7.41)
(5.98)
(4.92)
(1.68)
(6.50)
(6.46)
5.81
8.16
5.21
8.83
8.13
10.95
7.70
8.43
7.39
9.73
10.42
11.48
29.93
22.40
29.60
6.73
28.68
33.77
(0.48)
(0.72)
(0.44)
(0.70)
(0.81)
(0.64)
(0.41)
(0.71)
(0.48)
(0.65)
(0.70)
(0.64)
(3.30)
(2.32)
(2.73)
(1.12)
(2.41)
(2.11)
(7.55)
(6.88)
(5.28)
(2.05)
(6.24)
(7.87)
Blacks
182.15
136.30
69.48
25.69
128.15
99.35
~~~
~
6.00
7.70
4.95
8.32
8.25
11.10
7.40
8.01
6.52
9.11
9.88
11.74
32.75
23.07
30.17
7.35
31.00
35.95
182.20
137.25
71.57
23.42
138.30
105.60
(0.40)
(0.55)
(0.41)
(0.64)
(0.45)
(0.46)
(0.65)
(0.52)
(0.87)
(0.64)
(0.78)
(0.47)
(1.96)
(1.42)
(1.92)
(0.55)
(1.82)
(1.82)
(5.13)
(4.58)
(4.32)
(1.85)
(7.00)
(4.72)
Eskimos.~
(8.21)
(4.24)
(5.50)
(2.07)
(7.05)
(5.07)
5.69
7.54
4.80
8.29
7.72
10.66
7.46
8.09
7.01
9.21
10.04
11.34
(0.41)
(0.53)
(0.27)
(0.65)
(0.46)
(0.48)
(0.46)
(0.59)
(0.41)
(0.68)
(0.74)
(0.60)
28.37 (2.11)
20.79 (2.49)
29.10 (2.02)
7.34 (0.77)
29.08 (1.95)
34.98 (2.47)
175.80
145.45
71.20
26.77
136.05
98.80
Mongolians
5.66
7.79
4.92
8.10
7.75
10.79
7.63
8.16
6.67
9.04
9.80
11.46
32.66
21.11
28.22
7.49
29.33
35.45
176.80
135.65
70.38
25.42
134.10
102.60
(0.41)
(0.56)
(0.40)
(0.72)
(0.57)
(0.49)
(0.90)
(0.61)
(1.02)
(1.04)
(0.96)
(0.65)
(2.59)
(1.19)
(2.07)
(0.61)
(1.98)
(2.23)
(8.44)
(5.40)
(4.42)
(1.68)
(6.87)
(5.31)
Amerindians
F=
F=
2.58
2.70
4.55
3.65
3.60
2.58
3.28
1.31*
1.28*
4.96
3.88
1.81*
2.75
2.67
10.81
4.37
2.28*
2.86
8.69
3.41
F = 5.40
3.80
11.55
3.63
12.26
9.43
4.26
F = 7.49
F
6 6 in mml and uniuariate IF) and multiuatiate IWilks' A) variance ratios for one hundred human skulls.'
Whites
182.20
141.65
66.34
23.48
128.15
100.65
~~
Nontraditional craniometrics
basioccipital length
hasioccipital breadth
posterior nares breadth
carotid diameter
foramen magnum breadth
lacerum-jugular diameter
Traditional craniometrics
length
breadth
face height
nasal breadth
bizygomatic breadth
basicranial distance
~__.
TABLE 1. Basic descriptive statistics
0.530
0.469
0.365
0.130
Wilks'
lambda
U
>
z
126
D. FALK AND R. CORRUCCINI
The univariate data for cervical dental
measurements sort somewhat better than the
maximum dental measurements. All of the
F-ratios for cervical dentition were significantly greater than 1.0 while three of the six
F-ratios for the maximum dental data were not
significant at the 0.05 level. For both maximum and cervical dental measurements, the
third premolar was the best separator of
human groups (i.e., yielded the highest
F-ratios).
Multivariate analysis confirms the univariate results for cranial data. Traditional cranial
measurements easily provide the best separation of human populations (Wilks’lambda =
0.130),followed by nontraditional cranial measurements (0.365). However, contrary to the
univariate analysis, multivariate analysis of
maximum dental measurements is slightly
better at sorting human populations (Wilks’
lambda = 0.469) than cervical dental measurements (0.530).
tage that maximum dental data have over cervical dental data when the data are subjected
to multivariate analysis. Probably the higher
multivariate partition of variance for maximum dimensions relates to a lower level of intercorrelation than is characteristic for cervical dimensions. Perhaps the field effect differs
quantitatively, when studied by correlation,
between maximum (enamel) and cervical (cemento-enamel junction) dimensions.
We feel these results have implications for
local microdifferentiation and microevolution,
and substantiation should be sought in comparisons of closely related archeological
populations.
ACKNOWLEDGMENTS
DISCUSSION AND CONCLUSIONS
We thank Douglas Ubelaker of the United
States Museum of Natural History (Smithsonian Institution) for hospitality and access to
human osteological materials, John Karosas
for key punching data, and Southern Illinois
University for support for summer research
(DF).
Cranial measurements sort individuals in human populations better than do an equal number of dental measurements. We can think of
several possible reasons for this: (1)Tooth information may be more redundant because of
correlation. (2)Tooth size may be less heritable
than generally thought (Townsend and Brown,
1978% b; Garn et al., 1979). (3) Perhaps teeth
are less indicative of the major processes differentiating human races. (4)Teeth, because of
relatively ill-defined landmarks, may be subject to greater measurement error.
Within the cranial data, traditional measurements that span several bones proved to be
better than nontraditional basicranial
measurements that were each contained within one bone. It appears that the overall external shape of the skull may be more important in
evolutionary terms than its constituent parts
(including teeth). As emphasized by Howells
(1969), many of the traditional cranial measurements have high value for sorting major
human populations.
Finally, our results suggest that cervical
dental measurements are about as good for
sorting human groups as the traditional maximum dental measurements. Thus, by collecting cervical dental data, odontologists and
paleontologists can increase their sample sizes
since there is no need to discard worn teeth as
is the case when collecting maximum dental
measurements (Black, 1978). Such increase in
sample size might even offset the slight advan-
Anderson, TW (1958)An Introduction to Multivariate Statistical Analysis. New York: Wiley.
Black, TK (19781 A Method for Determining the Sex of Immature Human Skeletal Remains from Odontometric Dimensions. Ph.D. thesis, University of Michigan.
Black, TK (1979) Dental wear and dental rnetrics. Am. J.
Phys. Anthrop., 50:419-420 (abstract).
Broca, P (1874) Memoires Danthropologie. Vol. 2 Paris: C
Reinwald.
Butler, PM (1939)Studies of the mammalian dentition: differentiation of the post-canine dentition. Roc . 2001. Soc.
Lond.. 109B1-36.
Corruccini, RS (1974) An examination of the meaning of
cranial discrete traits for human skeletal biological
studies. Am. J.Phys. Anthrop.. 40:425-446.
Corruccini, RS (1977) Crown component variation in hominoid lower third molars. &it. Morph. Anthrop., a 1 4 - 2 5 .
Dahlberg, AA (1945)The changing dentition of man. J. Am.
Dent. Assoc.. 32:676-690.
De Quatrefages. A, and Hamy. E 11882) Les Cranes des
Races Humaines. Paris: J B Bailliere.
Garn, SM, Osborne, R, and McCahe, K 11979) The effect of
prenatal factors on crown dimensions. Am. J. Phys. A n
throp., 51:665-678.
Hanihara, K (1977) Distances between Australian aborigines and certain other populations based on dental measurernenls. J. Hum. Evol. 6403-418.
Harris, EF, and Nweeia. M (1980)Tooth size of Ticuna Indians, Columbia, with phenetic comparisons to other
Amerindians. Am. J. Phys. Anthrop.. 5381-91.
Henderson, AM 11975)Dental field theory: an application to
primate dental evolution. Ph.D. dissertation, University
of Colorado, Boulder.
Howells, WW (1969)Criteria for selection of osteometric dimensions. Am. J. Phys. Anthrop., 30:451-458.
Hrdlia a . A (1907) Skeletal remains suggesting or attributed to earty man in North America. Bureau of American
Ethnology. Bulletin 33, Washington, D.C.: Government
Publishing Office.
LITERATURE CITED
CRANIAL AND DENTAL MEASUREMENTS
Sofaer, JA, Bailit, HL and MacLean, CJ (1971) A developmental basis for differential tooth reduction in hominoid
evolution. Evolution, 25509-517.
Townsend, GC, and Brown, T (1978a)Heritability of permanent tooth size. Am. J. Phys. Anthrop., 49497-504.
127
Townsend. GC, and Brown, T (1978b) Inheritance of tooth
size in Australian aboriginals. Am. J. Phys. Anthrop.,
48305-314.
Wolpoff, M H (1971) Interstitial wear. Am. J. Phys. Anthrop., 34205-228.
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