Jurassic ammonites of Europe

thumb|Recreation of Hildoceras thumb|Hildoceras species from the Toarcian Bifrons Zone of the Gerecse Mts, Hungary. Collection Eötvös University, Dep. Palaeontology, Budapest. Hildoceras is a genus of ammonite from the Jurassic period in the family Hildoceratidae. The shells are characterized by a narrow discoidal evolute shape, keeled venter, concave ribs along the outer flanks, and a shallow spiral groove running along smooth inner flanks. Whorls slightly overlap, cross sections are compressed. The ventral keel is bordered on either side by a shallow groove. The genus was named by Alpheus Hy

Stephanoceras (meaning crown horn) is an extinct genus of Stephanoceratoid ammonite which lived during the Bajocian (Middle Jurassic). It is the type genus of the family Stephanoceratidae.