Marion Segall’s PhD defense. Water as a driver of evolution: the example of aquatic snakes

PhD defense on November 10th, at 2pm, in the auditorium of the Grande Galerie de l’Evolution.

Water as a driver of evolution: the example of aquatic snakes

Marion Segall

1. UMR 7179, CNRS-MNHN, Mécanismes adaptatifs et Evolution, équipe FUNEVOL, Département d’Ecologie et de Gestion de la Biodiversité. Pavillon d’anatomie comparée, 55 rue Buffon, case postale 55, 75231 Paris cedex 5, France.
2. UMR 7636, CNRS, ESPCI Paris–PSL Research University, Sorbonne Université, U Paris Diderot, Physique et Mécanique des Milieux Hétérogènes. 10 rue Vauquelin, 75005 Paris, France


Animal-environment interactions are determinant in driving the evolution of phenotypic variation. Most aquatic animals have developed adaptations to overcome the physical constraints inherent to an aquatic lifestyle and particularly to motion in water. These constraints are the drag and the added mass if an acceleration is involved in the motion, such as during prey capture. The aim of this project is to evaluate the role of water as a potential driver of evolution of aquatic snakes by focusing on morphological and behavioral convergences during underwater prey capture. Snakes are a good model as an aquatic life-style has originated independently in different genera. However, aquatic snakes did not develop a suction feeding system in contrast to most aquatic vertebrates. Prey-capture under water is constrained by the physical properties of the fluid and thus morphological and/or behavioral convergence is expected. By comparing the head shapes and the behavior of different species, we evaluated the impact of water on the evolution of head shape and strike behavior. By using experimental fluid mechanics approaches, we quantified the physical constraints involved in prey capture and evaluated the nature of the evolutionary response in response to these hydrodynamic constraints. This interdisciplinary approach allowed us to bring novel data to our understanding of functional constraints as drivers of phenotypic evolution.


Harvey LILLYWHITE (University of Florida) Rapporteur
Patricia ERN (Institut de Mécanique des Fluides de Toulouse) Rapporteur
Sam VAN WASSENBERGH (Universiteit Antwerpen) Examinateur
Catherine QUILLIET (Université Grenoble-Alpes) Examinateur
Anthony HERREL (Muséum National d’Histoire Naturelle) Directeur de thèse
Ramiro GODOY-DIANA (ESPCI Paris – CNRS) Directeur de thèse