Comparative Analysis of Nine Morphological Traits in Adult Female Mandibles from China Across Different Eras

This study examines nine morphological traits of female mandibles from the Holocene period (from over 7,000 years ago to the present).These traits include the heights of the condylar process, the lateral flaring of the mandibular angle, masseteric tuberosity, pterygoid tuberosity, mental spines, bridging of the mylohyoid groove, chin shape, mandibular prognathism, and rocking chair mandibles.Additionally, the study investigates potential temporal variations in these traits.Physical characteristics of the mandibles of 201 Holocene women from China were observed and classified.SPSS 19.0 software was used to calculate prevalence and perform significance tests of differences across periods.Variations were observed across different periods in the heights of the condylar process and the lateral flaring of the mandibular angle.After the Neolithic period, there was a significant decrease in the prominence of the masseteric tuberosity, and the pterygoid tuberosity also showed a marked reduction in the Bronze and Iron Ages compared to the Neolithic period.From the Neolithic to the modern era, the chin shape predominantly exhibited a "round" form, while the proportion of "pointed" chins continuously declined.Unlike the Neolithic and Bronze-Iron Ages, the modern population showed a 0.0 % occurrence of mylohyoid groove bridging, mandibular prognathism, and rocking chair mandibles.Changes in the related traits of the mandible may correlate with a reduction in its size over this period.Some traits might represent specialized manifestations or reflect a certain degree of primitiveness.