Xenarthra correspond to one of the major four eutherian mammal clades. Studies dealing with this magnaordem are abundant and diverse, covering topics such as ecology, medicine, physiology, evolution, among others. However, concerning the evolution of the group, little is known about the processes involved in the morphological diversification and the evolutionary consequences of each genus' genetic architecture in the evolution of their phenotypes. What is the importance of the constraints imposed by the modular organization in Xenarthran morphological diversification? What is the role of body size in the modular organization within this magnaorder? How does the line of least evolutionary resistance influence the morphological evolution of the group? Applying techniques of quantitative genetics, this project aims to answer the questions outlined above. For this purpose, the skull will be used as a study model and the analyses will be performed with linear distances from 2667 specimens measured, representing 12 of the 14 extant genera and seven from the several extinct genera. Based on the equation of the multivariate response to selection (z = P ²) and applying random selection gradient vectors (²), a series of statistics will be computed to understand how the variance/covariance phenotypic matrix (P) restricts the responsiveness in the evolution of mean characters (z) to the selective pressures (²). Also, metrics will be derived to assess if the morphological evolution between lineages occurred over the line of least evolutionary resistance and if this line affects the direction and magnitude of evolutionary change. In a broad perspective, the aim of this project is contribute to the growing knowledge about the morphological evolution of mammals as a whole.
News published in Agência FAPESP Newsletter about the scholarship: