Abstract
According to many investigations, changes in mandibular morphol-ogy can occur synchronously with changes in the environment,and sexual dimorphism of the mandible can be influenced by theenvironment. Sexual dimorphism during the last 1200 years wasevaluated using geometric morphometric analysis of virtual cranialmodels.
The method of geometric morphometrics allows differ-ences in size and shape to be assessed separately. We analyzedgroups of adult individuals dating to Early Middle Ages, High MiddleAges, Early Modern Ages and from a modern Czech population (21stcentury).
Significant sexual dimorphism in mandibular size wasfound in all populations. A trend in the sexual dimorphism of sizewas seen, with differences between the sexes increasing graduallyover time.
Size changes in female mandibles were a better reflec-tion of environmental conditions and climate than size changes inmale mandibles. Regarding changes in the sexual dimorphism ofshape, significant dimorphism was found in all four samples.
How-ever, the pattern of mandibular shape dimorphism was differentand varied considerably between samples. There was only one sta-ble shape trait showing sexual dimorphism across all four samplesin our study: the gonion lies more laterally in male than in female mandibles and male mandibles are relatively wider than femalemandibles.
Sexual dimorphism of shape is not influenced by theclimate; instead sexual selection might play a role. This researchsupports earlier studies that have found that the degree and pat-tern of sexual dimorphism is population-specific and the factorsregulating sexual dimorphism today may not be the same as thosein the past.