Mandibular ramus morphology of the Jomon people from Hokkaido

Abstract

Regional variations in mandibular ramus morphology were examined using five Jomon samples from Hokkaido, and Tohoku, Kanto, Tokai and Chugoku regions in Honshu (302 males and 263 females). The Hokkaido Epi-Jomon sample (15 males and 12 females) was also examined. The data of Hokkaido Ainu were used for investigation of temporal changes in Hokkaido region.The results indicated that the Hokkaido Jomon and Epi-Jomon have a broad mandibular ramus, which was significantly larger than those of other Jomon samples. And the Mahalanobis' distance analysis based on 5 mandibular measurements revealed that the Hokkaido prehistoric peoples were isolated from the Jomon in Honshu.Hokkaido Ainu had a narrower mandibular ramus than two other Hokkaido prehistoric samples. However, their ramus index was larger than those of the Jomon series in Honshu. Mandibular ramus has reduced from the Jomon to Modern period in Hokkaido, yet the Ainu still have relatively large mandibular ramus breadth.