From tooth to diet: a model for interpreting tooth microwear in modern-day caviomorph rodents

Abstract

Today, caviomorph rodents are a very diverse group belonging to numerous communities throughout the South American continent. Their evolutionary history shows several taxonomic radiation events over the last 40 million years, but their palaeoecology remains poorly explored. This paper proposes a tool to estimate the diet of fossil or poorly known taxa, using for the first time, modern methods of dental microwear texture analyses (DMTA) applied to a sample of 858 present-day specimens, representative of the group both taxonomically (38 genera) and ecologically. In parallel, an extensive literature review of the dietary preferences and behaviour of the studied species was carried out, and 11 dietary categories were described. By associating dental microwear texture data with corresponding ecological data, a group-scale framework for estimating caviomorph diet from dental microwear is proposed. Differences in dental microwear are detected among all dietary categories. Thus, consumers of soft items, such as shoots and flowers, have shallow and non-complex textures, in contrast to consumers of abrasive items, such as ripe leaves or roots. Consumers of hard elements, such as seeds and insects, show medium values with higher variation. Although several limits are identified, these interpretative trends allow for an estimation of the diet in fossil taxa, and to further our understanding of the evolutionary history of caviomorphs in their ecological and environmental dimension through time.