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Dental topographic analysis is a suite of measurements designed to capture functional information about occlusal morphology that can be effectively applied to wear series. Recent studies have revealed that some primate folivores exhibit an apparent improvement in dental function (i.e., increased occlusal sharpness) with increased wear—a phenomenon termed ‘dental sculpting.’ While dental sculpting has been identified in a folivorous platyrrhine (Alouatta) and colobine (Presbytis), its prevalence across primate phylogeny and ecomorphology remains underexplored. A wear series of 13 bonobo (Pan paniscus) second mandibular molars were analyzed for dental topography and amount of wear. 3D surfaces were generated in Avizo from μCT data of specimens housed at the Royal Belgian Institute of Natural Sciences representing the broadest range of wear states available. Occlusal sharpness was measured as convex Dirichlet normal energy (DNE) using the R package molaR. Wear was quantified as the dentine exposure ratio (DER) by imaging specimens in occlusal view and measuring the ratio of exposed dentine area to total occlusal area. Linear regression analysis found that DNE declined significantly with increased DER (p= 0.002), with moderate explanatory power (r2= 0.555). These findings suggest that dental sculpting does not occur in Pan paniscus. Our results contrast with those found for the frugivorous platyrrhines Ateles and Plecturocebus, who maintain DNE with wear. Rather, they indicate that bonobos lack compensatory mechanisms to preserve occlusal sharpness across their lifespans and underscore the importance of nutrition gained through relatively soft dietary materials that do not require significant cutting or slicing to efficiently consume. 

Amorphous solids lack long-range order. Therefore identifying structural defects—akin to dislocations in crystalline solids—that carry plastic flow in these systems remains a daunting challenge. By comparing many different structural indicators in computational models of glasses, under a variety of conditions we carefully assess which of these indicators are able to robustly identify the structural defects responsible for plastic flow in amorphous solids. We further demonstrate that the density of defects changes as a function of material preparation and strain in a manner that is highly correlated with the macroscopic material response. Our work represents an important step towards predicting how and when an amorphous solid will fail from its microscopic structure.