Choristoceratidae

The Choristoceratidae is a family of ceratitid ammonites assigned to the Clydonitaceae known from the upper Triassic in which the outer whorls tend to diverge and may become straight. Initial coiling is evolute. Whorls are ribbed, sutures gonititic or weakly ceratitc. Genera include Choristoceras, Hannoceras, Peripleurites, and Rhabdoceras.