A study of the facial flatness in several cranial series from East Asia and North America.

Abstract

Three sets of facial flatness measurements were taken of five Mongoloid cranial series from North America, and two Mongoloid and one Caucasoid cranial series from East Asia. The data of the Ainu and Japanese quoted from YAMAGUCHI (1973) were also used as a comparison. The definitions of measurements and indices of flatness were the same as described by YAMAGUCHI (l, c.). Correlation between sexes measured by the SPEARMAN rank correlation coefficient was considerably high in each of the frontal, simotic, and zygomaxillary indices. High correlation between the two sexes was also observed in PENROSE shape distances based on the three sets of measurements. From three-dimensional diagrams of the three indices of flatness, it was inferred that the combination of frontal and zygomaxillary indices was more effective than that of the frontal and simotic indices in differentiating Mongoloid and Caucasoid groupings from each other. The principal co-ordinates analyses on the basis of the matrix of PENROSE shape distances showed that, though they were within the range of variation of the Mongoloid series, the Japanese and Ontario Iroquois formed a cluster, as did the Canadian Eskimos and Inupik-speaking Alaskan Eskimos. In regard to the facial flattening, the Ainu was far closer to the Mongoloid series than to the Caucasoid series. It was confirmed that the Eskimo's face was characterized by extremely flat frontal and zygomaxillary regions and pronounced nasal bones. The causation of the reduced but prominent, or pinched , nasal bones of the Eskimos was briefly discussed.