Estimating the body size of eocene primates: A comparison of results from dental and postcranial variables

Estimating body weights for fossil primates is an important step in reconstructing aspects of their behavior and ecology. To date, the body size of Eocene euprimates—the Adapidae and Omomyidae—has been estimated only from molar area. Studies on other primates and mammals demonstrate that body weights estimated from teeth are not always concordant with those estimated from postcranial variables. We derive estimates for Eocene primates based on tarsal bone variables to compare with previously published values derived from dental measures. Stepsirhine-wide, family-level, and subfamily-level models are developed and compared. We also compare the accuracy and precision of dental- and tarsal-based regression models for predicting weight in extant species. Tarsal bone and dental area measures prove to be equally robust in predicting body weight; however, highly disparate estimates are often obtained from different variables. Equations based on lower-level taxonomic groups perform better than more widely based models. However, all equations considered yield fairly large errors, which can affect interpretations of paleoecology. The choice of the more robust prediction is not straightforward.