This project will focus on the ontogenetic origin of the structural biodiversity of the head in a highly diverse group of South American catfishes, i.e. the genus Corydoras. Of this genus, almost nothing is known about the morphology of head structures and their ontogeny. This research will focus on the ontogeny of these head structures (skeleton and muscles) in one species on a microscopic-anatomical level. These results will then be compared to those of related species.