Acipenseriformes /æsɨˈpɛnsərɨˈfɔrmiːz/ are an order of basal ray-finned fishes that includes the sturgeons and paddlefishes, as well as some extinct families.Notable characteristics of Acipenseriformes include: Cartilaginous endoskeleton Lack of vertebral centrum Spiral valve intestine Conus arteriosus↑ ↑ ↑