School of Human Evolution and Social Change, Institute of Human Origins, Arizona State University
Saturday All day, Plaza Level
Establishing the competitive environments surrounding the evolutionary origins of primate groups is contingent on accurately identifying dietary competition between fossil primates and their mammalian contemporaries. This requires the reconstruction of dietary niche overlap among extinct species using associations between dental morphology and dietary regimes in related extant taxa. These associations must hold across primates and their likely dietary competitors ("primate competitive guild") to directly compare species' niches. Competition is expected to occur within broad dietary categories (e.g., insectivory), but in studies of diet-dentition relationships across primate competitive guilds, more restricted dietary classifications have rarely been employed. This study's objective was to determine whether molar morphological variables are associated with specific dietary niches within an extant primate competitive guild.
Three-dimensional measurements of molar form were obtained from 73 species (Primates, Chiroptera, Marsupialia, Rodentia) from a single locality (Balta,Peru). Dietary categories were subdivided to create "operational dietary units" (ODUs), and species were assigned to ODUs based on a series of parameters, arranged hierarchically: primary dietary component, relative proportions of food resources, specific dietary items, and canopy foraging level. Principal components analysis was used to demonstrate separation of ODUs, and canonical discriminant analysis was performed to identify the measures that maximized variation among ODUs. Results indicated that ODUs were differentiable within dietary categories by cusp sharpness, crest length, basin depth, and cusp height (first two principal components explained ~85% of the variation in the sample). These results provide an initial step towards refining reconstructions of dietary competition in the primate fossil record.
This project was funded in part by Sigma Xi.