Cardioceras

Cardioceras is an extinct ammonite genus belonging to the family Cardioceratidae. These fast-moving nektonic carnivores lived during the Jurassic period, Oxfordian age.^[2][3]

Cardioceras Temporal range: Jurassic, 161.2–155.7 Ma PreꞒ Ꞓ O S D C P T J K Pg N [1]
Fossil of Cardioceras persecans from France, on display at Galerie de paléontologie et d'anatomie comparée in Paris
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Cephalopoda
Subclass:	†Ammonoidea
Order:	†Ammonitida
Family:	†Cardioceratidae
Genus:	†Cardioceras Neumayr & Uhlig, 1881

Description

Shells of Cardioceras species can reach a diameter of 20–25 millimetres (0.79–0.98 in).^[4] The shape is circular, with ribs and a prominent ridge along the dorsal edge.^[5]

Distribution

Fossils of species within this genus have been found in the Jurassic of France, Germany, Poland, Russia, the United Kingdom^[1] and Alaska.^[6]