 A recent classification divides the Tarphycerida into suborders Tarphycerina and Barrandeocerina, which were previously defined as separate orders.Tarphycerids are more closely related to the diverse Oncocerida, through the ancestral Bassleroceratidae in the Lower Ordovician, than to the other nautiloid orders.The Oncocerida, in turn, gave rise to the Nautilida which include the recent "Nautilus" and "Allonautilus".