séminaire - mardi 29 août 2017

First approximation to evolutionary patterns of jaw shape and biomechanical performance in extant armadillos

Soledad De Esteban Trivigno

mardi 29 août 2017



Xenarthra is one of the four major clades of placentals. They were highly diverse in the past and, despite their reduced number of current species, they still occupy a quite large range of ecological niches and environments. Armadillos (Cingulata) are the most diverse group of living xenarthrans, what make them suitable for the evaluation of evolutionary trends and pressures within this clade. Their mandible-skull complex show a very high disparity compared with other groups of mammals. Specifically, the mandible is a simple structure but with a large disparity, and it is expected to be affected by ecological adaptations. The objective of this work is to explore the evolutionary patterns of shape change of the cingulate lower jaw, taking into account its covariation with biomechanical characteristics. Geometric morphometric methods were used to generate shape variables. On the other hand, Finite Element Analyses (FEA) were developed on the same mandibles. From the FEA we obtained specific indicators of biomechanical performance, being these indicators related to the diet of each species. We coupled this information with the shape changes and phylogenetic comparative methods to understand those changes in an evolutionary framework.