Human skeletal remains from the Tochibara rock-shelter site (Earliest Jomon, Nagano pref., Central Japan), and re-evaluation of the characteristics of the Earliest Jomon people

Abstract

Eight adult and four infant human remains dating back to the Earliest Jomon age, excavated in the Tochibara rock-shelter site, Nagano prefecture, Central Japan, exhibited general Jomon features, such as low facial height, pilasteric femur, and marked tooth abrasion. They show specific features of the Earliest and Early Jomon people--an extremely short face and a small mandible with a thin corpus. Although their face was small, masticatory function might have been well-developed. In the male skeletons, the lower limb bones are almost equal in thickness to those of Later and Latest Jomon males, but the upper limb bones are more slender than those of Late and Latest Jomon males. The female upper and lower limb bones are almost equal in thickness to those of Later and Latest Jomon females. Considerable change might have occurred in the way of life of Early to Late Jomon men, for example, from nomadic to stable residence, as well as from pure gathering/hunting to gathering/hunting with primitive agriculture. The skeletons also exhibit various pathological lesions, such as enamel hypoplasia, Harris's lines, osteoarthritis in the mandibular joint, carious teeth, and radicular cysts, which imply that the daily life of the Earliest Jomon people was difficult. By comparison of the Tochibara skeletons with other Jomon skeletons, the so-called specific features of Earliest and Early Jomon skeletons were re-confirmed, with some modifications: 1) extremely short face, 2) small mandible but wide and forward-projecting coronoid process, 3) slender upper limb bones, and 4) heavy abrasion of mandibular teeth. Recently, it was suggested that the Jomon people were not homogeneous but consisted of various subgroups, according to their mt-DNA haplotype. The specific morphological features of the Earliest and Early Jomon people must be considered from the viewpoints of both phylogenetic differences and change in life-style. [PUBLICATION ABSTRACT]