What is "macrocephalites"

Macrocephalites is a genus of the stephanoceratacean ammonite family Macrocephalitidae, diagnostic of the Callovian stage of the Middle Jurassic. Three subgenera, Dolikephalites, Kamptokephalites, and Pleurocephalite are recognized in addition to Macrocephalites itself, with Indocephalites tentatively included as the fourth.