EVOMORPH — Theme PVC - Phylogeny and Complex Morphological Variations

How can we extract the phylogenetic signal from complex morphological variations?

• Led by Isabelle Rouget and Véronique Barriel

The phylogenetic signal carried by the morphological variation of organisms is an essential source for placing extinct taxa in the Tree of Life. However, interpreting morphological traits is rarely straightforward. Our research addresses major challenges such as morphological integration (trait covariation), frequent evolutionary convergence, and the difficulty of establishing robust homology hypotheses. We aim to develop reasoned solutions to these challenges, enhancing the robustness of phylogenies through a multi-scale characterization of anatomical variation and its ties to ontogenetic and functional attributes. Leveraging expertise in anatomy, morphometrics, phylogenetics and probabilistic modeling, we analyze evolutionary patterns in models prone to high integration, such as serial homologies (teeth, vertebrae, limbs) in vertebrates and arthropods, cephalopod shells, and jaws of these three groups. 

Modelling the evolution of cingular crests on the molars of placentals. A) Observation of a simplified example on three successive molars (M1, M2, M3). B) Phylogenetic distribution: green indicates the presence of the crest on a given molar, and black indicates its absence. C) Best-fit character model and estimated transition rates for the evolution of this trait: eight states (1-8) represent all possible combinations of cingular crest distribution on the three molars. See more details in Billet & Bardin (2019)....