Metric sexual dimorphism of the skull in Thailand

The increasing recognition in forensic anthropology of variation in sexual dimorphism of skull size and shape among and within human populations has increased motivation among researchers to collect craniometric data from regional populations. Modern high levels of migration on an international scale has contributed to this endeavour, as has increasing understanding of historic population histories across the world. Mainland Southeast Asia is a region that has a complex population history. A large sample of male and female skulls (n = 322) selected from a collection of donated modern skeletons from northeast Thailand is used in this study to provide reliable data on the pattern of sexual dimorphism in the region. The data from these skulls is analysed using both univariate and multivariate statistics to derive discriminant functions that can be applied in sex estimation during personal identification. The results from the analyses are compared with those derived from other modern skeletal collections from northern and central Thailand. This shows that variation across the country is minimal. An on-line method of easily applying the results of the analysis to data from unknown skeletons is presented and freely available for use by practitioners of forensic anthropology. •Cranial sexual dimorphism varies among human populations.•Skull sex estimation needs craniometric data from regional populations of known sex.•Craniometric data from a large sample of modern northeast Thai skulls are analysed.•The results can be used to sex unknown skulls from all regions of Thailand.•A freely-available app is provided for estimating sex of an unknown Thai skull.