Wikipedia
Austiniceras is a subgenus of Parapuzosia, the shell of which is commonly large, moderately involute, high whorled, with flat or convex sides that converge on a narrowly rounded venter. Primary ribs are signoid or concave. Constrictions where present are rather shallow. The related subgenus P. Parapuzosia differs in having a more oval whorl section, stronger and straighter primary ribs, and a smooth outer whorl.
Parapuzosia (Austiniceras) has a rather long temporal range. It is known from Lower Cenomanian to Upper Turonian sediments in western Europe and from the Coiniaian to the Campanian of Madagascar, and is recorded from Japan, North Aftrica, and North America (Texas).
Parapuzosia is an extinct genus of desmoceratid ammonites from the Cenomanian to the Campanian of Africa, Europe, and North America. They are typically very large ammonites, reaching diameters of or more, with the largest species measuring upwards of more than . It possess a moderately involute shell with flat or slightly rounded sides. Distinct primary and secondary ribbing can be observed in the inner whorls.