Preauricular grooves in women are considered as an indicator of childbirth or pregnancy. We examined 522 female pelvises excavated from archaeological sites in Edo (present-day Tokyo), Japan, which underwent population growth during the Edo period (AD 1603–1867). We analyzed the frequency of preauricular grooves by estimated age group, burial period, and type of burial facility in Edo to infer age-related changes and chronological as well as social-rank-related differences during the Edo period. We found that the frequency of preauricular grooves increased with individual age. Moreover, a higher frequency of developed preauricular grooves was observed during and after the 18th century (the middle–late Edo period) compared with those observed in the 17th century (early Edo period) in all age groups. The frequencies of preauricular grooves in remains buried in kamekan (ceramic coffins) and hayaoke (circular wooden coffins) revealed no social differentiation of reproduction rate. These results suggest that the average number of births per woman during and after the 18th century may have exceeded that in the 17th century. Consequently, it is highly probable that the population increase known to occur in Edo during the 17th century was caused by an influx from rural areas rather than by an increasing number of births among the city’s female residents. Furthermore, the number of pregnancies and births did not differ significantly among different social classes during the later Edo period.

This article examines an unusual small-sized omichicahuaztli from Tenochtitlan. Omichicahuaztlis are artifacts that were made out of long bones with incisions and, likely, functioned as musical instruments. The referred bone from the Mexica (Aztec) culture (1250–1521 CE) is exhibited at the Museo Nacional de Antropología in Mexico City. It has been identified either as a human or as a monkey bone. However, until now, it has not been studied in detail to test both contentions. Our morphological and morphometric analyses indicate that this specimen is from a platyrrhine femur (conferred to a Mexican spider monkey), and to our knowledge, it is the only of its kind among the Mexica and elsewhere in Mesoamerica. Archeoprimatologicaly, this unique omichicahuaztli stands together with confirmed findings of spider monkeys skins from a couple of offerings of the Templo Mayor of Tenochtitlan, and with other primate osteological remains apparently found in two other Mexica sites. Ethnohistorically, among the Mexica (Aztec), the spider monkey is the most represented primate and is usually related to the notion of fertility. The Mexica perception of primates ranges from the use of bones and skins in medicine to the connection of giving birth on a particular day related to musical inclinations. In summary, the symbolic connotations of Mexica perceptions of primates appear to be embodied in this specimen. This omichicahuaztli also serves as evidence of the circulation of an allochthonous mammal from the tropical lowlands to Tenochtitlan highlands.

We describe a small catarrhine talus discovered in Nachola, northern Kenya. Although Nacholapithecus, Nyanzapithecus, and Victoriapithecus are known from Nachola, this talus is too tiny to be assigned to a female Nacholapithecus. It is also different in shape from both Nacholapithecus and Victoriapithecus. Hence, it is best to assign it to Nyanzapithecus, whose tarsal features were not known before. We compared this talus to tali of other small Miocene catarrhines from Kenya and several extant catarrhines. The estimated body mass of this specimen is 5.2–5.5 kg, depending on the regression formula. It is distinguished from comparative taxa by the feeble development of the malleolar cup, which is a stabilizing mechanism of the talocrural joint at the full dorsiflexion, and a low trochlea, suggesting that the talocrural joint was not specialized for rapid extension-flexion. These features suggest that Nyanzapithecus walked and ran in the trees with less agility and did not frequently engage in leaping. Additionally, it has a wide posteroinferior surface of the trochlea with a straight lateral border, probably enhancing the talocrural joint’s full plantarflexion. This might be suggestive of hindlimb suspension.

This brief communication documents a case of tarsal coalition in a 15-year-old (± 30 months) adolescent from the Old Burial Ground in Heuvelton, New York. Macroscopic examination revealed pseudoarticulation, along with bilateral bony changes such as nodular bone, trabecular exposure, and porosity on the calcanei, naviculars, cuboids, and tali. These features were identified as bilateral non-osseous calcaneonavicular coalition. This case is significant as it is one of the few identified from a North American historical archaeological context, providing insight into the health conditions affecting a young settler in 19th-century rural upstate New York.

Several reports have raised concerns about poor posture in children worldwide. As Japan began to experience rapid economic growth toward the end of the 20th century, poor posture (hyperkyphosis) in children became a particular problem. However, little research has been conducted on hyperkyphosis among Japanese elementary school students, and sample sizes have been inadequate. This study aimed to determine the prevalence and characteristics of hyperkyphosis among Japanese elementary school students to help understand and prevent hyperkyphosis. A total of 403 Japanese elementary school students (208 boys and 195 girls) were enrolled in this study. The SpinalMouse system was used to measure thoracic kyphosis and upper thoracic, lower thoracic, lumbar lordosis, and sacral anteversion angles in the standing position. Hyperkyphosis was defined as a thoracic kyphosis angle of >40°. The participants were assigned to two groups: hyperkyphosis and non-hyperkyphosis. The prevalence of hyperkyphosis among Japanese elementary school students was approximately 25.0%. The upper and lower thoracic kyphosis angles were compared separately. The hyperkyphosis group had a significantly higher degree of kyphosis (upper and lower) than the non-hyperkyphosis group. The lumbar lordosis angle was significantly greater in the hyperkyphosis group than in the non-hyperkyphosis group. Additionally, the upper thoracic spine angle was significantly greater than the lower thoracic spine angle in the hyperkyphosis group. A strong negative correlation was found between the lumbar lordosis angle and sacral anteversion angles in both groups. The results of this study indicated a hyperkyphosis prevalence of approximately 25% and suggested that the upper thoracic spine may be characterized by a greater degree of kyphosis in Japanese elementary school students.