Research Project

In geographically widely-spread clades, like the carnivorans of South America, traits may vary across a climatic gradient. This variation can be potentially explained by ecogeographical rules, such as Bergmann’s and Resource rules, and by allometric rules, like Rensch’s rule. Bergmann predicted that an enhance of body size would be selected at higher latitudes (colder environments) as an adaptation to avoid heat loss to the external environment. Resource’s rule foresees that size increases in relation to patterns of variation, in space and/or time, of the type and amount of resource available at different areas, creating conditions that may favour animal growth rates. Lastly, Rensch’s rule predicts that the enhancement of sexual dimorphism is associated to the increase of species size. Given these, sexual dimorphism could interact with ecogeographical patterns. Although these ecogeographical rules were originally described in relation to animal size variation, their idea can potentially be extended to animal shape as well. This is due to the fact that animal shape (especially their feeding apparatus) has a functional component that is related to animals feeding ecology, in addition to the intrinsic association of size and shape variation (= allometry). Within this context, we propose to evaluate the association of allometry, climatic variation and sexual dimorphism in the mandibular morphology of South-American carnivores. In order to understand how ecogeographic and allometric rules associate within a macroevolutionary context, we intend to analyse the mandible shape variation of twenty species of Carnivora. We planned a stepwise procedure of analytical models that will work interactive between intra and interspecific data in order to analyse allometric, ecogeographical and sexual variation at different scales. This framework can potentially be suitable for multiple biological models, contributing for the advances of evolutionary studies at large scales.