Meeting Abstract
Caudata display a great diversity of developmental strategies directly impacting their morphology and the exploitation of their environment during their ontogeny. Several different developmental strategies have evolved independently during the evolution of Caudata. For example, some species exhibit direct development, hatching directly as a terrestrial phenotype, whereas others are paedomorphic, keeping aquatic larval traits even if they are reproductively active. Others species have a complex life cycle with bi-phasic development, allowing them to exploit different environments during morphologically different life history stages. The aim of this study is to test the impact of the complexity of life cycles and ecology on the cranial shape evolution. To do so, high-density geometric morphometric and integration methods were performed to characterize the shape of 14 regions of the cranium for 145 species spanning the full phylogenetic, ecological, and developmental breadth of Caudata. Each cranial region was analysed separately to detect mosaic evolution and test for a relationship between magnitude of integration, morphological disparity, and evolutionary rate. Morphological integration, modularity, and disparity analyses were carried out in order to test if a complex life cycle promotes phenotypic disparity and modularity, whereas paedomorphic or direct development strategies promote morphological integration and constrain shape variability. Finally, rates of shape evolution were calculated for each developmental strategy in order to test increased or decreased rates of evolution were associated with complexity of life cycle. Specifically, if a complex developmental strategy tends to constrains cranial shape, then an implication of the developmental strategies should increase the evolutionary rate of the cranium.
