A Human Skull of the Epi-Jomon Period from the Minami-Usu Six Site, Date, Hokkaido

Abstract

An adult female skull of the Epi-Jomon period (Esan culture) found at the Minami-Usu 6 site, Date, southern Hokkaido, was measured and described. Metrically, the skull was characterized, among other things, by a relatively long vault and a moderately high upper face. Morphological observations revealed that the facial skeleton of the skull was as a whole reduced in size as compared with that of Jomon crania, while attrition of the teeth was well advanced arid had reached Stage III or IV, as is frequently seen in Jomon crania. PENROSE's shape distances, based on 21 measurements, showed that the Minami-Usu 6 skull was closer to the skulls of the Ainu series than to those of the Jomon series in Honshu. Of the six cranial indices which have been effective in discriminating between Ainu and Jomon crania, four indices suggested the close affinity of the Minami-Usu 6 skull with the Ainu series. With regard to the indices of facial flatness, the frontal and simotic indices of flatness of the Minami-Usu 6 skull were intermediate between the averages of the Ainu and Jomon series, with only the zygomaxillary index of flatness exceeding the averages of both the Ainu and Jomon series. A likelihood ratio analysis of the non-metric cranial variants applied for the Ainu and modern Japanese, based on 29 traits, indicated that the Minami-Usu 6 skull was far more likely to have come from the Ainu population than from the Japanese population. Taking all the results obtained from this study into consideration, it was concluded that the total morphological pattern of the Minami-Usu 6 skull was slightly closer to that of the Ainu series, especially to that of the Ainu in southwestern Hokkaido, than to that of the Jomon series in Honshu.