IBERIA

Project Description.

Why do Neandertals and modern humans have such different crania? This project will clarify this over one century long question by testing if Neandertals were adapted to heavy biting/paramastication and so if Neandertals diverge from the overall trend in Homo of decreased masticatory demands. This will feed the debate about Neandertal heavy dietary reliance on mechanically demanding foodstuffs such as meat.

The biomechanical interpretation that Neandertals were adapted to heavy biting/paramastication is based on studies showing that Neandertals were capable of generating/withstanding heavy biting, and present extreme, atypical dental wear with scratching of the anterior teeth. This suggests they were engaging in heavy biting and using their teeth to hold and manipulate artefacts. Yet, other studies suggest otherwise, specifically: H. sapiens is able to generate higher bite forces than Neandertals; incisor size of Neandertal is comparable to early Homo; anterior dental wear of Late Pleistocene H. sapiens is heavier than in Neandertals.

After over one century of research, it is unclear if Neandertals were adapted to heavy biting/paramastication. If so, they deviate from the trend in Homo for decreased masticatory demands and gracilization of the masticatory system. This uncertainty is because most studies are qualitative, use 2D representations of cranial anatomy and greatly simplify cranial form. Most studies also only compare Neandertals with recent modern humans that do not engage in heavy biting/paramastication, neglecting a relevant comparative sample that includes ancestral morphologies and functionally comparable specimens. This project aims to resolve this debate using a wide comparative sample and a cutting-edge experimental morphology toolkit. The sample will include CT/surface scanned crania of Neandertals, ancestral specimens (e.g., H. heildelbergensis), early H. sapiens and recent H. sapiens who do and don’t engage in heavy biting/paramastication. Imaging and surface modelling software will be used to create 3D models based on the scans and restore the anatomy of incomplete specimens. Geometric Morphometrics (GM) will be used to examine morphology and virtually manipulate morphological traits of hypothesized mechanical relevance. Finite Element Analysis (FEA) will be used to perform complex simulations of biting/paramastication and predict the functional performance of the different specimens. FEA allows modelling of the material properties of skeletal/dental tissues, muscle forces and directions and constraining of models, providing realistic predictions of the masticatory/paramasticatory performance of different specimens. GM will be used to assess the relationship between cranial form and function. If Neandertals were indeed adapted to heavy biting/paramastication, they will perform better (i.e., deform less) than ancestral specimens and H. sapiens.