Dental Perspectives on Human Evolution: State of the Art Research in Dental Paleoanthropology

Abstract

Dental functional morphology can inform us on the dietaryadaptations of early hominins and other fossil primates. Traditionalapproaches to understanding dental form-function relationships haverelied mostly on unworn teeth for analysis. This has limited oursamples and our understanding of how teeth are adapted to wear in amanner that keeps them mechanically efficient for chewing. Thispaper reviews a relatively new tool for the study of occlusalfunctional morphology, dental topographic analysis. Thislandmark-free, three-dimensional approach involves the creation andmeasurement of digital models of teeth using point cloud data andGeographic Information Systems software. Three examples arepresented. First, a study of living great apes is reviewed to showthat worn teeth can be included in the study of dental topography,and that species with different diets have corresponding andpredictable differences in the shapes of their molars at comparablestages of tooth wear. Second, a longitudinal study of howlingmonkeys is summarized to demonstrate that different individualswithin this species have consistent changes in crown shape as theirteeth wear down. This suggests species-specific wear patterns, anecessary prerequisite for the inference of function from form ofworn fossil teeth. Third, a new dental topographic analysis ispresented for Australopithecus africanus and Paranthropusrobustus to illustrate that this approach can offer insights intothe dietary adaptations of early hominins and other fossil primates.Results presented here confirm that the A. africanus and P. robustus differed in their dietary adaptations. The degree ofdifference between their occlusal morphologies is on the orderexpected of species that often eat similar foods, but differ at “crunch” times. Dental topography data suggest that P.robustus probably fell back more on hard, brittle items whereasA. africanus relied on tougher, more elastic foods when preferred resources were less available.