Diplomoceras
Diplomoceras is a genus of ammonites included in the family Diplomoceratidae. Fossils of species within this genus have been found in the Late Cretaceous sediments. D. maximum had coiled shell length about, uncoiled shell being to over, with body chamber around. Some partial specimens may belong to shell with length around. Studies of Diplomoceras suggest that members of this genus could reach lifespans of over 200 years.