Ammonitida genera

Didymoceras is an extinct genus of ammonite cephalopod from the Late Cretaceous epoch (approximately 76 Ma). It is one of the most bizarrely shaped genera, with a shell that spirals upwards into a loose, hooked tip. It is thought to have drifted in the water vertically, moving up and down. The genus name comes from Ancient Greek δίδυμος (dídumos), meaning "twin", and κέρας (céras), meaning "horn".

Otoites is the type genus of the ammonite family Otoitidae that live during the Middle Jurassic.

Polyptychoceras is an extinct genus of ammonites from the Late Cretaceous of Asia, Europe, and North and South America. It was first named by Hisakatsu Yabe in 1927.

Neocomites is a genus of ammonite from the Lower Cretaceous, Berriasian to Hauterivian, and type genus for the Neocomitidae.

thumb|200 px|Spitidiscus seunesi (Wilfrid Kilian|Kilian) [[Barremian, Brestak, Cr1 426X1 (Coll. St. Breskovski) at the Sofia University Museum of Paleontology and Historical Geology]] Spitidiscus is a genus of ammonites placed in the family Holcodiscidae.

Hoploscaphites is an extinct ammonite genus from the Upper Cretaceous and the Lower Paleocene, included in the family Scaphitidae.

Aegoceras is an evolutionary wound ammonite, with wide spaced ribs, from the Early Jurassic (England) included in the Liparoceratidae and superfamily Eoderoceratidae. Leparoceras is a related genus.

Acrioceras is an extinct genus of cephalopods belonging to the ammonite subclass.

Balearites is an extinct ancyloceratin genus included in the family Crioceratitidae, subclass Ammonoidea, from the Upper Hauterivian.

Prodactylioceras is genus of ammonite that lived during the Pliensbachian stage of early Jurassic. It has evolved from Reynesocoeloceras, but maybe not directly, but through Bettoniceras. Its fossils were found in Europe, Asia and North America.