9404752 Ausich PI will attempt to delineate major aspects of the morphological diversification of the Crinoidea (crinoids) during their early history in Cambrian to Ordovician time (c. 450-500 million years ago). Crinoids were among the most important marine organisms throughout the Paleozoic, and are still living in today's oceans. PI will also construct a phylogenetic classification of the Crinoidea, and identify evolutionary trends, addressing diversification in a context of community ecology.