Аннотация:Intraspecific variability of a modern human mandible was determined using a principal component analisis following by a varimax rotation. Individual standardized data for the following series were included in the analysis: Eskimo from Ekven, 4-7 cen. AD, - 61 jaws; Eskimo from Naukan, 19-20 cen. AD, - 23 jaws; Anglo-Saxon from Dunstable, 5-6 cen. AD, - 40 jaws (Dingwall, Yaung, 1933); Ancient Egyptian series, IX dynasty, - 37 jaws (Woo, 1930); series of Badari culture, Egypt, 5-3 cen. BC, - 32 jaws (Stossiger, 1927); Hokiens, southeast China, early 20 century, - 38 jaws (Harrower, 1928); Hylams, island Hainan, China, - 39 jaws (Harrower, 1928); Tamils, India and Ceylon, - 33 jaws (Harrower, 1928).
During the analysis three principle components (PC-1, 2, 3) were determined. The first PC describes the overall size of a bone and is not associated with angular dimensions. PC-2 characterizes the variability of a mandibular angle (M-79) and a height of branches (M-70). PC-3 strongly correlates with a height of a symphysis (M-69) and an angle of a chin protrusion (<C’).
We found that the Eskimo series have the largest jaws, while the bones from the ancient Egypt and the Tamils series are the smallest. By this we show that PC-1 reveals the presence of ecological gradient on the mandible dimension. We discovered that a mandibular angle and a height of branches are related negatively, therefore jaws with a vertically oriented high branch occupy the maximum values pole and jaws with short inclined branch are in the minimum values region. The first group of jaws pertain to Anglo-Saxons, the other one is typical to Eskimo from Ekven. Hylams’ jaws show the maximum variability along the PC-1 and PC-2. From the PC-3 we obtain the greater the angle of a chin, the higher the symphysis is, and vice versa. Jaws of Eskimo and Hokiens have the highest chin, the jaws of Tamils, Anglo-Saxons and Hylams are low and protrusive.
On the plot below we show an individual value of PC for each of the mandible. Jaws of Eskimo take up a marginal position in all PC. This is related, probably, to extreme conditions of their habitat. Hokiens’ jaws are the most morphologically similar to Eskimos series. Opposite poles of the PC are occupied by different Caucasoid series.