Dental wear refers to the gradual loss of dental hard tissues, and its patterns are greatly affected by dietary habits. This study examined dental wear in the Jomon people, prehistoric hunter-gatherers of the Japanese archipelago, to determine whether molar wear rate was relatively fast or slow compared with that of other hunter-gatherer populations with different dietary habits. To evaluate the rate of dental wear, we used average score differences between adjacent molars. Considering that this parameter is independent of age, we compared the Jomon wear rate value with those of the other hunter-gatherers and pastoralist populations available in the literature. Results indicated that the Jomon people had a significantly lower rate of wear compared to populations in arid regions with a higher reliance on abrasive plant-based diets. Furthermore, the Jomon wear rate was comparable to or lower than that of populations in cold climate with less dependency on plant foods. We suggest that the low rate of wear seen in the Jomon people stems from the use of pottery, accompanied by an increased reliance on carbohydrates, possibly associated with changes in cooking methods.

During the Edo period in Japan, the Makino family served for generations as the feudal lords of the Nagaoka domain, which ruled the northern part of the Chuetsu region and the western part of the Kaetsu region in present-day Niigata Prefecture. Two different family histories have been handed down regarding Makino Tadahiro, the 8th lord of the Nagaoka domain. According to official records, Tadahiro was from the Kasama Makino family (relatives of the Nagaoka Makino family). However, an unofficial record of the Nagaoka Makino family states that Tadahiro was the biological son of the 5th lord of Nagaoka, Makino Tadachika. Why two different records were passed down to posterity together, and which of these records is correct, are extremely interesting historical mysteries. To verify which of these records is correct, we conducted a kinship study by the autosomal and Y-chromosome short tandem repeat analysis of three individuals: Tadahiro, Tadachika, and the 4th lord of Nagaoka, Tadanaga (the biological father of Tadachika). The results showed it was highly probable that these three individuals have a grandfather–father–son relationship. This is the first report to use DNA analysis to prove which of several family trees of the feudal lords of the Nagaoka domain is correct.

As a sizable component of the cranial vault, the parietal bone is essential for understanding the regional variation of cranial surface morphology. Predigital, traditional morphological studies have tended to underemphasize the role of parietal trait variation, particularly in identifying region-specific and/or sex-related differences in modern human populations. Consequently, the extent of morphological variation in the parietal bone among modern human populations remains insufficiently understood. In this study, we perform a three-dimensional (3D) geometric morphometric analysis of the external surface of the parietal bone, using microcomputed tomography data from 120 human crania (60 males and 60 females) sampled from European and Chinese populations. The analysis of the periosteal surface of the parietal bone reveals significant sexual dimorphism in shape space. Specifically, the biparietal distance between pterion landmarks is wider in Chinese males than in Chinese females. Regional differences in parietal bone shape are more frequently statistically significant. Parietal bones of European populations tend to be wider and shorter, with less pronounced parietal eminences, whereas those from Chinese populations are relatively narrower and longer, exhibiting more prominent parietal eminences. When 3D geometric morphometric analysis is conducted in form space, which incorporates both shape and size, additional differences between sexes and populations become evident. Males exhibit significantly larger parietal bones than females, and individuals from European populations have significantly larger parietal bones than those from Chinese populations. Ultimately, differences in form space are more pronounced than those in shape space, emphasizing the importance of considering both shape and size in morphological analyses.

People of the Jomon period in Japan led a hunter-gatherer lifestyle and actively engaged in fishing in coastal areas. On the Atsumi Peninsula, which is located in the southern part of Aichi Prefecture, a number of shell mounds from the Jomon period have been located. More than 30 human skeletal remains have been excavated from the Kawaji shell mound, located at the tip of the Atsumi Peninsula. The Kawaji shell mound was formed from the Middle to Final Jomon period and is thought to be mainly from the Late Jomon period. This study aimed to investigate temporal changes in diet and their relationships with subsistence activities and mortuary practices, which include types of ritual tooth ablation and the location pattern of burials within the site, during the Jomon period. The study material consisted of 20 human skeletal samples from the Kawaji shell mound. Diet was inferred using carbon and nitrogen isotope analysis of bone collagen, and age by radiocarbon dating. Age showed values from the late Middle to the Final Jomon and the Initial to Middle Yayoi periods. Dietary dependence on marine resources increased during the Late Jomon period, and then decreased in the Initial to Middle Yayoi periods. Transition patterns in ritual tooth ablation were also found. Burial subgroups within the shell mound were recognized in each phase. The findings from this case study help shed light on the temporal changes that occurred in the subsistence activities and mortuary practices of the Jomon people.

A severe case of kyphoscoliosis was observed in the skeletal remains of a male from the late Edo period in Japan. This individual exhibited left curvature thoracic scoliosis and kyphotic deformity, with ankylosis of the fifth to twelfth thoracic vertebrae at the intervertebral joints. The Cobb angle was 77° and the kyphotic angle was 76°. The superior articular facet of the cervical vertebrae was lower on the left side than the right side. Additionally, the sacral base was inclined to the right, resulting in the superior articular process and facet being lower on the right than on the left. These observations suggest compensatory right curvature of the cervical and lower lumbar spine. The rib morphology was asymmetrical, with the right ribs being obtusely angled and spreading laterally, while the left ribs were acutely angled and directed medially. These findings indicate that this individual had severe structural left-convex thoracic kyphoscoliosis. The possible underlying conditions considered in this case included idiopathic scoliosis or syringomyelia. This is the first detailed report of severe kyphoscoliosis in archaeological skeletal remains excavated from the Japanese Archipelago.