Pampush et al. Atelidae Adaptive Dental Topography Dynamics
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ID: 00000C509
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Primates are generally characterized by low-crowned, brachydont molars relative to many other groups of mammals. This conservative architecture may create special challenges for maintaining dental functionality in the case of a diet requiring proficient shearing ability (e.g, folivory). One recent hypothesis—the ‘enamel sculpting hypothesis’—suggests that such primates express dentition that functionally harnesses macrowear in maintaining occlusal sharpness. We examined the relationships between four dental topography metrics (DNE=Dirichlet Normal Energy, OPCR=Orientation Patch Count Rotated, RFI=Relief Index, and OR=Occlusal Relief) against macrowear (as measured with DER=Dentine Exposure Ratio) in lower first molars of Ateles and Alouatta—two closely related platyrrhines with distinct diets (Alouatta=folivore, Ateles=frugivore). We find support for the enamel sculpting hypothesis, in that DNE increases with macrowear in the folivorous Alouatta but not in the frugivorous Ateles. Multiple contradictions between OPCR and the other variables suggest this metric is a poor reflection of the molar form-function relationship in these primates. Distributions of relief measures (RFI and OR) confound expectations and prior observations, in that Ateles shows higher values than Alouatta, since these measures are thought to be correlated with dental shearing ability. We discuss the role Ateles’ relatively thicker enamel caps may play in the distributions of these metrics.