Desmoceratoidea

Pachydiscus is an extinct genus of ammonite from the Late Cretaceous and Early Paleocene with a worldwide distribution, and type for the desmoceratacean family Pachydiscidae. The genus' type species is P. neubergicus. Altogether some 28 species have been described.

Astieridiscus is an extinct lower Cretaceous ammonite. Its shell evolute, covered by dense, simple or branching, slightly flexuous ribs. The sides are slightly flattened, the venter rounded. No umbilical or other tubercles except on innermost whorl. Superficially resembles Olcostephanus.

Lewesiceras is a genus of large ammonites belonging to the order Ammonitida and the family Pachydiscidae.

Holcodiscus is an extinct ammonite genus placed in the family Holcodiscidae. Species in this genus were fast-moving nektonic carnivores. The type species of the genus is Ammonites caillaudianus.

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.

Desmoceratidae is a family belonging to the ammonite superfamily Desmoceratoidea. They are an extinct group of ammonoids, shelled cephalopods related to squid, belemnites, octopuses, and cuttlefish, and more distantly to the nautiloids, that lived between the Lower Cretaceous (Upper Valanginian) and Upper Cretaceous (Upper Maastrichtian).