Shape evolution in mammalian carnivores (Order Carnivora): a “phylo-morphometric” approach.

PREVOSTI FRANCISCO J.; TURAZZINI GUILLERMO F.; ERCOLI MARCOS D.

Punta del Este

Congreso; IX International Congress of Vertebrate Morphology; 2010

The morphology of the mandible and the lower dentition carry information regarding the diet of different species of carnivores. Consequently, several studies were published analyzing the relationship between the shape of the mandible and the dietary habits, based on different methods such as morphometric indexes and traditional morphometrics (i.e. multivariate statistics using measurements). Other works explored the presence of constraints or modularity in the mandibles, but the evolution of mandible shape in a phylogenetic framework remains unknown. We use new algorithms that allow the optimization of geometric morphometric configurations on phylogenetic trees to explore the evolution of mandibular shape in living carnivores. The optimization of the shape of the mandible on the phylogeny shows that most internal nodes have generalized shapes and most of the extreme changes take place at terminal branches, which correspond to “derived” species or genera (e.g. Potos flavus). Some interesting changes of the shape happen at Family nodes, for example Ursidae has a short and strong ramus, an anteriorly placed carnassial and a large canine, while Canidae has longer and slender horizontal ramus when compared to internal nodes of the phylogeny. The relationship between shape and changes in size in the whole tree remains unclear, but some of those changes can happen in the same node (e.g. Ursidae presents an increment in size and while changes to a different mandible pattern). This optimization must be tested in the future including a better sample of fossils.