P. Mitteroecker1, P. Gunz1, M. Teschler-Nicola2, GW. Weber1
1 Vienna Inst. for Anthropology, Vienna Austria
2 Museum of Natural History Vienna, Austria

We provide a shape analysis of a Middle Neolithic (4900-4300 BC) human cranium introducing a new tool to geometric morphometrics: semilandmarks on surfaces.
Two hydrocephalics (34 and 12 years old) and a control group of morphologically regular formed crania (N=20) ranging from 2 years of age to adults are compared against an adolescent middle Neolithic specimen which is presumably hydrocephalic.
42 anatomical landmarks and several thousand points on the neurocranial surface were either digitised using a Polhemus device or extracted from CT-data. Our algorithm automatically places 336 semilandmarks on the neurocranium and relaxes them against the Procrustes average preserving just information perpendicular to the surface. These three dimensional semilandmarks offer the opportunity of incorporating information about curved forms that lack traditional landmarks into statistical shape analysis.
While all 3 hydrocephalics possess very prominent parietal bosses, the Neolithic hydrocephalus is different in frontal bone shape, lying close to the variability obtained in the control group. This suggests that the Neolithic specimen could represent a case of acquired hydrocephalus where the sutures at the parietal and occipital region of the skull still had enough degrees of freedom to compensate the intracranial pressure, while the frontal suture had already fused.
Project grant of the FWF-Austrian Science Foundation, P14738.
Key words: Semilandmarks, Geometric Morphometrics, Hydrocephalus, Paleopathology