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Johnston, Francis E.; Hamill, Peter V. V.; Lemeshow, Stanley
doi: 10.1002/ajpa.1330400302pmid: 4826455
Cycles II and III of the Health Examination Survey included measurements of the skinfolds of over 14,000 individuals 6 through 17 years of age, statistically weighted to provide an accurate national probability sample. Analyses of the triceps and subscapular skinfolds of Negroes and whites are reported here, utilizing the median in preference to the mean. Females of either racial group have thicker skinfolds at all ages studied. Whites have greater median triceps thicknesses than Negroes of the same sex and age, but there are no differences between the two racial groups in the subscapular. Since, between all but one pair of adjacent ages in males, from 12 years on, the median triceps fold decreases, but the estimated cross‐sectional are of fat increases, it is strongly recommended that reductions in triceps thickness not be automatically interpreted as meaning a loss of subcutaneous fat. Since greater skewness is found in the subscapular distributions in whites, but not in the triceps, it is suggested that racial differences in triceps thickness at these ages occurs from the operation of hereditary factors, while differences in the subscapular skinfold arise from environmental causes.
Salzano, F. M.; De Sá E Benevides Fº, F. R.
doi: 10.1002/ajpa.1330400303pmid: N/A
A total of 432 Whites and 654 Blacks were studied in relation to the index of pattern intensity and a smaller number (296 Whites; 496 Blacks) for total ridge count. There does not exist a clear gradient in either sex when the Blacks are subdivided into three phenotypic categories according to the amount of African ancestry they seem to possess. The standard deviations and coefficients of variation are strikingly similar in all groups studied. Racial differences in the averages of these two quantitative measures and in the asymmetry of total ridge count are small and nonsignificant. Fingerprints are very sensitive indicators of disturbances in the intrauterine development, and their asymmetry has a significant hereditary component. Since there is no increased or decreased asymmetry when we consider subgroups with various amounts of racial admixture, these and other results suggest that genetic adaptation in humans is a process involving mainly the whole species, and not narrow racial specializations.
doi: 10.1002/ajpa.1330400304pmid: N/A
Stature of the African early hominids is estimated from most of the available fragments of fossil long bones by means of regression analysis. The average height of the South African gracile australopithecines is predicted to be 145.1 cm (4′9″) where n = 4 and of the South African robust forms, 152.7 cm (5′) where n = 3. The East African early hominids are somewhat taller (x = 163.0 cm or 5′4″, where n = 7). Variability in stature is high even within the same site which is probably a reflection of fairly strong sexual dimorphism in body size.
Kemper, H. C. G.; Pieters, J. J. L.
doi: 10.1002/ajpa.1330400305pmid: 4826456
The objectivity of several anthropometric measurements were tested in two institutes on the same subjects.
doi: 10.1002/ajpa.1330400306pmid: N/A
The incidences of 30 non‐metrical skull variants have been determined in 21 samples of crania from Scandinavia, Iceland and the British Isles. The samples have been compared to give Estimates of Divergence which are assumed to represent degrees of genetical affinity between them.
doi: 10.1002/ajpa.1330400307pmid: 4207857
A study was made of ranges of variation of the anterior dentition of various African nonhuman primates. Comparisons of the dentitions were made between different species and sex differences within each species were determined. Among the nonhuman primate groups studied were: Gorilla gorilla gorilla, Pan troglodytes, Pan paniscus, Cercopithecus nictitans, Cercocebus albigena and Colobus badius. In monkeys the canine teeth of the males are considerably larger than those of the females. There are also considerable differences in size in the rest of the anterior dentition. In apes, and specifically only gorillas, distinct sex differences are only found in the maxillary canines. In the chimpanzees, sex differences in the dentition are much smaller and there is considerable overlap in the ranges of variation. There are no fundamental differences in the size of the rest of the anterior dentition in the apes. The present study shows that differences due to sex in the anterior dentition, excluding the canine, are not as great as has been considered. If we consider the fossil record of man, whose morphological complex includes a much reduced canine, the probability will be that sex differences in the rest of the dentition will be negligible. Given the fragmentary nature of the fossil record, it is, therefore, highly unlikely that the determination of the sex of any fossil hominid specimen can be accurately made based solely on the evidence of its dentition.
doi: 10.1002/ajpa.1330400308pmid: 4826457
Variation in number of presacral vertebrae (PSV) was examined in 462 vertebral columns in four populations drawn from tribal groups of Southern African Negroes. The total incidence of numerical variants (23 PSV and 25 PSV) was 19% in males and 12.1% in females. Males have a higher frequency of 25 PSV and females a higher frequency of 23 PSV, a sex difference reported by previous workers. Significant differences in the incidence of 25 PSV in males were present between S.A. Negroes, American Negroes and other racial groups. The total number of variants (23 PSV and 25 PSV) is significantly higher in S.A. Negro males (and higher but not significantly in females) than in the other groups; owing mainly to the findings in the Nguni‐speaking sub‐samples of the S.A. Negro. These findings support a previous suggestion based on combined‐sex data that the frequency of numerical variations of PSV are characteristic of a population. It is suggested here that such frequencies are even more characteristic when males and females are considered separately.
doi: 10.1002/ajpa.1330400309pmid: N/A
Ischial callosities are specialised regions of skin and subdermal tissue in the form of fibro‐fatty cushions with a tough, non‐slip surface, firmly bound to the underlying ischial tuberosity. They occur in primates of the families Cercopithecidae and Hylobatidae. Ischial callosity usage helps animals to adopt stable sitting postures on the tops of branches, particularly during feeding, resting and sleeping. Callosity‐like areas in pongids are mainly epidermal specialisations and differ in their development and usage from true callosities. They are similar to the para‐callosity skin regions in some ground living cercopithecids. The ischial tuberosity in animals with true callosities has a flat surface which flares out from the lower end of the ischial body and which is devoid of muscle attachments. In animals without callosities the ischial tuberosity is not flared, has a curved surface, and acts as a site for muscle attachment. The ischial tuberosity is relatively broader in animals with callosities than in animals without callosities, although the absolute size of the specimens concerned must be taken into account. The combination of qualitative and quantitative features of fossil ischial tuberosities enables the presence or absence of callosities in these forms to be deduced. The recognition of these features in fossil material might be of use in the elucidation of the evolution of one type of primate arboreal adaptation.
doi: 10.1002/ajpa.1330400310pmid: 4826458
Approximal grooving of teeth is a form of tooth wear seen in some fossil hominids (Neandertal Man and Pekin Man) and in some primitive peoples (Bushmen, Australian aborigines and American Indians). Previous workers have claimed the grooves were produced either by an acid secreted from the gum or by constant probings with a tooth‐pick. The purpose of this paper is to refute these hypotheses, and to suggest from observations on the morphology of the grooves in four Bushman skulls, one American Indian skull, and one South African Negro skull that the approximal grooves are produced by dietary grit (sand and soil in the food and drinking water) being sucked from the vestibule into the oral cavity proper during the mouth‐cleansing phase of swallowing.
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