Homoplasy and thick enamel in primates

Area of Science:

• Paleoanthropology
• Primate Paleontology
• Dental Anthropology

Background:

• Thick enamel in extinct hominins is traditionally linked to hard object feeding (durophagy).
• This inference assumes thick enamel prevents tooth fracture from high-stress mastication.
• An alternative hypothesis suggests thick enamel resists gradual wear from abrasive foods and acids.

Purpose of the Study:

• To test if enamel thickness is selectively responsive to lifetime dental wear resistance.
• To investigate the relationship between primate enamel thickness, dietary abrasiveness, and lifespan.

Main Methods:

• Compiled data on enamel thickness, dietary abrasiveness, diet profiles, and longevity for 17 primate species.
• Performed linear regression analyses using various combinations of these variables.

Main Results:

• A positive association was found between lifetime dietary wear and enamel thickness.
• This suggests thick molar enamel in primates may have evolved primarily to resist wear.

Conclusions:

• Thick enamel in primates may be an adaptation to resist wear, independent of selection for resisting tooth fracture.
• Paleoanthropological interpretations of thick enamel should consider primate lifespan and broader feeding ecology, not solely hard-object feeding.