Ecological and spatial overlap indicate interspecific competition during North American Canid radiation

Understanding biodiversity patterns and the processes that generate them are key goals in ecology and macroevolutionary studies. Diversity-dependent models of diversification have been used to indirectly infer the relevance of interspecific competition on driving speciation and extinction dynamics. In this study, we develop a new approach that more explicitly incorporated spatial and eco-morphological overlap among species to test how interspecific competition my affect diversification dynamics at deep time. We built different metrics that capture not only species temporal coexistence, but also their coexistence in space and morphospace to test the hypothesis that an increase in the intensity of competition would result in both a decrease in speciation rate and an increase in extinction rate. We tested our predictions using the North American fossil record of the family Canidae, a group that has been extensively studied and well characterized both from the eco-morphological and paleontological points of view. We found that interspecific competition only affected diversification dynamics during the early stages of Canidae radiation, resulting only in the suppression of speciation rate at the time the clade was expanding in diversity. We found no association between the intensity of the competition and extinction dynamics as expected by a competitive model, nor an association between changes in speciation and extinction rates and changes in global temperature, suggesting that extinction dynamics might be more related to external factors, such as clade-competition. We discuss the relevance of different factors on driving diversification dynamics changes over time and how evaluating the role of interspecific competition using different metrics that better capture the intensity of competition (as opposed to diversity dependent models), might be a way forward to investigate the role of biotic interactions at deep time.