 Ascocerida

The Ascocerida are comparatively small, bizarre Orthoceratoids known only from Ordovician and Silurian sediments in Europe and North America, uniquely characterized by a deciduous conch consisting of a longiconic juvenile portion and an inflated breviconic adult portion that separate sometime in maturity.The juvenile portion of an ascocerid consists typically of a narrow, circular cyrtocone that underwent periodic truncation.