Cranial secular change from the nineteenth to the twentieth century in modern German individuals compared to modern Euro-American individuals

Katharina Jellinghaus, Katharina Hoeland, Carolin Hachmann, Andreas Prescher, Michael Bohnert, Richard Jantz

Studying secular changes on human skulls is a central issue in anthropological research, which is however insufficiently investigated for modern German populations. With our study, we focus on morphological cranial variations within Germans during the nineteenth and twentieth centuries. To study this, we recorded different facial landmarks from a cohort study of about 540 German individuals of different age and sex by calculating their cranial size, shape dimensions, and cranial module and cranial capacity to get information about variations occurring during the decades. According to this, measured variables for Germans and Americans, to which we compared our results, were maximum cranial length (glabello-occipital length), basion-bregma height (BBH), basion-nasion length (BNL), maximum cranial breadth (XCB), and cranial base breadth (AUB). Cranial size was calculated as the geometric mean of GOL, BBH, and XCB. Samples were organized into quarter century birth cohorts, with birth years ranging from 1800 to 1950. One-way ANOVA was used to test for variation among cohorts. Over the past 150 years, Americans and Germans showed significant parallel changes, but the American cranium remained relatively higher, with a longer cranial base, as well as narrower than the German cranium. Our results should also lead to the extension of the range of populations listed and investigated for Fordisc®, a forensic software to identify unknown individuals as from their skeletal remains or just parts of them. Fordisc cannot provide a satisfying identification of European individuals yet because the database is missing enough European reference samples.