close

Вход

Забыли?

вход по аккаунту

?

Observations on the teeth of the mountain gorilla (Gorilla gorilla beringei).

код для вставкиСкачать
Observations on the Teeth of the Mountain Gorilla
(Gorilla gorilla beringei)
S A N D R A N. BOOTH
Department of Anthropology, University of W i s c o n s i n ,
Madison, W i s c o n s i n 53706
ABSTRACT
Measurements of a sample of mountain gorilla (Gorilla gorilla
beringei) teeth are presented; when compared with other Gorilla series, the di-
mensions of the maxillary teeth fall in the upper end of the observed range for
the genus. All of the upper teeth except the canine show a greater sex difference
in the bucco-lingual diameter than in the mesio-distal dimension. This is also
true for the other hominoids which have been studied, man, the chimpanzee, and
the orang-utan, but to a lesser degree in man and the chimpanzee.
Until the present time measurements
of the teeth of mountain gorillas (Gorillu gorilla beringei) appearing in the
literature have not been considered
apart from those of the lowland subspecies (G. g . gorilla). To correct this deficiency, dental measurements taken on
a recently collected sample of mountain
gorillas are given here.
MATERIAL A N D METHODS
The sample consists of the maxillary
teeth of five adult males, five adult females, seven juveniles, and the mandibular teeth of three adult males, one adult
female. and two juveniles. Not all of these
sets of teeth are complete. The crania and
mandibles were collected i n the eastern
Congo at three localities, which are described in detail by Schaller (’63).
Measurements were made of the teeth
in situ on the right side of the jam except when teeth on this side were broken
or missing, in which case those of the
left side were measured instead. Vernier
sliding calipers were used and measurements were recorded to the nearest 0.1
mm. The following measurements have
been included in the present study:
buccomesio-distal
diameter (M-D),
lingual diameter (B-L), crown height
(Ht), trigon breadth (TrB) and talon
breadth (TaB) for the molars, and certain tooth row measurements (Incisor
row and C-M3).
AM. J. PKYS. ANTKROP.,34: 85-88.
RESULTS A N D DISCUSSION
The maxillary and mandibular tooth
dimensions of the adult male gorillas
are shown in table 1 and the maxillary
and mandibular tooth dimensions of the
adult female gorillas in table 2. In table
3 upper and lower tooth measurements
of the juvenile specimens are given.
Since the sample size is small the raw
data are given so that they can be of
use to other investigators.
When the mean length and breadth
of the upper molars of the mountain
gorillas are compared with the corresponding values of other gorilla series,
they either fall within the range of the
other series or extend beyond the upper
end of the range of the observed values.
The fact that other investigators do not
distinguish data obtained from mountain gorillas from those of lowland gorillas renders comparison between subspecies diEcult.
Remane’s (‘21) large sample of gorilla
teeth (N = 322), which includes mountain gorilla material, has a considerable
range of variation, entirely overlapping
that of the present series. The present
series does, however, fall at the upper
end of that range. The mean length and
breadth values given by Ashton and
Zuckerman (‘50) for Gorilla teeth are
consistently exceeded by the present
series; this is shown in percentage terms
in table 4. Both of these comparisons
85
SANDRA N. BOOTH
86
TABLE 1
Tooth dimensions of male mountain gorillas (in mm)
Tooth and
measurement
Specimen no.
Ht
M-D
B-L
HtM-D
B-L
Ht
M-D
B -L
M-D
B-L
M-D
B-L
I1
I2
C
P3
P4
M-D
M1
TrB
M2
TaB
M-D
TrB
TaB
M-D
TrB
TaB
Incisor row
C-M3
M3
Maxilla
8
19
13.0
13.5
11.4
13.0
10.6
12.5
23.4
21.4
17.2
12.0
16.4
12.1
16.5
15.4
17.5
16.1
17.0
17.8
17.4
15.7
16.8
15.1
47.0
94.0
11.6
12.2
15.9
15.5
15.9
15.6
18.2
16.9
16.6
17.0
90.0
Mandible
6
14
10.0
12.8
11.3
9.6
9.5
11.4
25.3
21 .o
14.0
11.3
17.4
11.7
17.0
14.6
16.4
16.9
16.5
18.4
16.9
15.5
16.9
15.0
13.5
16.9
17.4
18.4
17.6
88.0
11.0
8.9
11.2
25.8
21.2
17.0
11.8
17.5
10.8
17.5
16.5
16.7
16.5
17.9
17.9
18.2
17.4
17.3
15.5
45.0
94.0
2
19
1
12.0
8.4
10.7
13.5
9.2
11.9
23.1
17.9
14.4
17.5
12.2
12.9
13.8
16.6
14.8
14.8
18.6
17.0
15.5
19.2
17.0
14.9
33.0
103.0
11.4
8.1
10.0
13.9
11.6
1
17.3
12.0
12.5
14.2
17.8
14.9
14.8
19.6
16.5
16.6
20.0
16.9
15.4
33.0
104.0
17.4
13.5
13.2
16.1
18.6
16.7
16.1
20.7
18.4
17.8
20.0
17.9
15.1
TABLE 2
Tooth dimensions of female mountain gorillas (in mm)
Tooth and
measurement
Saecimen no
I1
Ht
M-D
B-L
12
Ht
C
M-D
B-L
Ht
M-D
B-L
M1
M-D
B-L
M-D
B-L
M-D
M2
TrB
TaB
M-D
P3
P4
TrB
TaB
M-D
TrB
TaB
Incisor row
C-M3
Maxilla
17
9.1
9.2
8.5
15.3
14.6
11.1
10.9
16.6
11.1
15.7
15.9
16.4
15.6
16.5
17.4
16.4
M3
suggest that mountain
are somewhat larger
gorilla molars. Further,
and mandibular tooth
40.0
12.7
13.9
10.3
9.6
10.4
10.3
16.0
15.9
11.5
11.1
16.0
11.1
15.2
15.7
15.9
16.2
17.0
17.7
16.5
17.1
16.9
13.4
42.0
86.0
gorilla molars
than lowland
the maxillary
row measure-
Mandible
12
10
13.3
12.0
9.8
10.8
9.0
9.9
16.1
14.3
11.9
11.2
15.5
11.3
15.3
11.4
12.9
10.5
11
17.0
16.9
15.7
15.5
15.3
13.5
38.0
83.0
~~
3
17
11.4
7.9
9.4
11.6
10.0
10.4
14.3
11.9
11.3
16.3
12.0
15.4
14.4
15.5
15.3
16.3
17.0
15.9
15.3
15.4
__ .
12.5
40.0
82.0
15.0
11.3
11.0
15.9
11.8
15.1
16.5
15.6
15.8
17.5
16.5
16.6
16.4
~~
16.0
- -
14.3
39.0
85.5
13.5
13.4
12.4
13.6
16.7
14.3
14.8
18.9
16.1
15.2
17.0
14.7
13.7
89.0
ments (C-M3) closely resemble values
cited by Coolidge (‘29) for 33 mountain
gorillas; these values were found to be
significantly larger (P < 0.01) than
87
OBSERVATIONS ON MOUNTAIN GORILLA TEETH
TABLE 3
Tooth dimensions ofjuvenile m o u n t a i n gorillas (in m m ]
Tooth and
measurement
Specimen no.
Ht
I1
M-D
B-L
Ht
M-n
12
B-L
Ht
M-D
B-L
P3
M-D
B-L
P4
M-D
B -L
d m l M-D
B-L
Maxilla
16
5
15.2
13.5
11.0
13.3
9.9
10.6
15.2
12.4
10.5
dc
12.9
17.8
12.6
17.5
d m 2 M-D
B-L
M1
M-D
16.6
17.2
16.8
18.7
18.4
17.3
TrB
T aR
M2
M-D
TrB
TaB
1
2
I\?laiidiblr
____
3
9
7
16
5
12.0
7.8
9.0
12.8
8.8
10.2
7.0 I
8.6
6.7
4.8 2
5.5
6.4
8.9
9.8
12.4
10.7
8.6
11.7
16.4
16.2
15.5
15.4
16.4
16.0
15.2
4
11.5
9.2
7.6
15.5
11.3
9.7
11.0
13.7
13.1
16.4
16.0
15.8
14.4
14.1
18.5
9.8
11.5
13.6
13.4
12.7
14.1
12.3
18.5
15.1
14.7
19.9
16.9
16.0
16.8
14.0
14.0
17.9
14.9
14.6
8.8
10.9
13.0
12.4
11.8
Deciduous central incisor.
Deciduous lateral incisor.
TABLE 4
Percentage difference between m e u n dimensions of the upper molars. Mountain gorillas
(present series) (N = 7-10)m i n u s t h e Gorilla series ( N = 20-35)of Ashton
and Zucherman ('SO), t h e latter values t a k e n as 100%
Percentage difference between samples
Tooth
Sex
Mi
M
F
M
F
M
F
M2
MJ
Crown length
Crown breadth
3.3
9.2
6.7
12.7
5.8
16.9
6.3
6.3
6.5
11.1
5.6
11.9
values obtained from his lowland series
(Haddow and Ross, '51).
Percentage sex differences were calculated for the dimensions of the upper
teeth (table 5 ) , with the female values
being taken as 100%. On the average
the teeth of males are 9.6% larger than
those of females; the range is from
-8.7 to 39.0%. For every tooth measured, except the canine, the mean sex
difference is greater for the bucco-lingual diameter than for the mesio-distal
diameter or the height dimension i n the
incisors. This phenomenon is also apparent i n the orang-utan (data from
Ashton and Zuckerman, 'SO), and to a
considerably lesser degree in the chimpanzee (data from Ashton and Zuckerman, '50, and Schuman and Brace, '55).
Data presented by Garn et al. ('66) for
American Whites suggest that man
slightly exceeds the chimp with respect
to this feature of sexual dimorphism.
SUMMARY AND CONCLUSIONS
The maxillary teeth of a collection of
mountain gorilla skulls were found to be
similar in size to teeth representative
of the species Gorilla gorilla as a whole,
and there are indications that the mean
88
SANDRA N. BOOTH
TABLE 5
Percentage s e x difference ( m a l e m i n u s fernale)
in t h e maxillary teeth of t h e m o u n t a i n
gorilla (female values t a k e n as 100% 1
Tooth and
measurement
I'
I2
C
P3
P4
M'
Mz
M3
Ht
M-D
B-L
Ht
M-D
B-L
Ht
M-D
B -L
M-D
B-L
M-D
B-L
M-D
TrB
TaB
M-D
TrB
TaB
M-D
TrB
TaB
Mean sex difference
N
4
5
5
7
7
7
7
8
8
9
8
10
10
8
8
8
10
10
10
8
7
7
Percentage sex
difference
- 8.7
1.7
9.8
8.1
0.0
17.3
39.0
31.4
28.0
4.8
5.9
4.0
8.7
- 1.3
6.3
3.2
2.5
5.0
6.5
3.0
5.9
29.8
9.6
dimensions of the mountain gorilla (G.
g. beringei) teeth exceed those of the
lowland subspecies (G. g. gorilla). In
the upper dentition bucco-lingual dimensions of all the teeth except the
canine exhibit greater sexual dimorphism than mesio-distal dimensions.
ACKNOWLEDGMENTS
I should like to thank Dr. W. S. Laughlin, University of Connecticut, and Dr.
J. T. Emlen, University of Wisconsin,
Madison, for making available the material used in this study, and Dr. R. H.
Osborne for criticism of the manuscript.
This work was supported by a National
Institute of Dental Research predoctoral
fell0wship.
LITERATURE CITED
Ashton, E. H., and S. Zuckerman 1950 Some
quantitative dental characteristics of the chimpanzee, gorilla, and orang-outang. Phil. Trans.
Roy. SOC., London, Series B, 234: 471-484.
Coolidge, H. J. 1929 A revision of the genus
Gorilla. Mem. Mus. Comp. Zool., Harvard,
50: 293-381.
Garn, S. M., A. B. Lewis and R. S. Kerewsky
1966 Sexual dimorphism i n the buccolingual
tooth diameter. J. Dent. Res., 4 5 ; 1819.
Haddow, A. J., and R. W. Ross 1951 A critical
review of Coolidge's measurements of gorilla
skulls. Proc. Zool. SOC.,London, 121; 43-54.
Remane, A. 1921 Beitrage zur Morphologie
des Anthropoidengebisses. Archiv f. Naturgesch., 87 (Abt. A, No. 11): 1-179.
Schaller, G. B. 1963 The Mountain Gorilla;
Ecology and Behavior. University of Chicago
Press, Chicago.
Schuman, E. L., and C. L. Brace 1955 Metric
and morphological variations in the dentition
of the Liberian chimpanzee; comparisons with
anthropoid and human dentitions. In: The
Non-human Primates and Human Evolution.
J. A. Gavan, ed., Wayne University Press,
Detroit.
Документ
Категория
Без категории
Просмотров
2
Размер файла
225 Кб
Теги
beringei, mountain, observations, gorillas, teeth
1/--страниц
Пожаловаться на содержимое документа