What is "coroniceras"

Coroniceras is a genus in the Arietitidae, a family in the ammonitid superfamily Psiloceratiaceae, from the lower Sinermurian stage in the Lower Jurassic. It is a sub zone ammonite of the Arnioceras semicostotum Zone

Coroniceras has a thin discoidal form with a circular whorl section, arched venter, single tall keel, and few but strong ribs. Coroniceras is included in the subfamily Arietitinae

Fossils of Coroniceras bucklandi are commonly found at Lyme Regis, Dorset Coast, England in the higher limestones of the Blue Lias.