Etude de la variation morphologique au cours de l'ontogénie des poissons téléostéens associés aux récifs coralliens

Abstract

Phenotypic variation within populations are essential for biological evolution. Indeed, phenotypic variation can serve as the raw products upon which natural selection acts. Accordingly, we might question if the level of morphological variation (i.e.disparity) might vary over the ontogeny of one species. Here, I test the hypothetical variation of body shape disparity level between post-larval and adult stages in coral reef fishes. Landmark-based geometric morphometrics methods were used to quantify body shapevariation during ontogeny for four species from Moorea Island (French Polynesia) : the surgeonfishes Acanthurus triostegus and Ctenochaetus striatus, the damselfish Chromis viridis, and the cardinalfish Pristiapogon exostigma. First, post-larvae and adults significantly differ in their body shape, and these variations were discussed in a ecomorphological context. Except C.viridis, all the species showed a higher level of morphological disparity at adult stage than at larval stage. This could be explained by a hyper-specialization of C.viridis in the adult stage for habitat use while the other species can use more habitats in the adult stage than in the post-larval stage.