Pachydiscidae

Pachydiscidae; Temporal range: 99.6–66 Ma PreꞒ Ꞓ O S D C P T J K Pg N Cenomanian - Maastrichtian
	Eupachydiscus isculensis from Cretaceous – Bergamo (Italy)
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Cephalopoda
Subclass:	†Ammonoidea
Order:	†Ammonitida
Superfamily:	†Desmoceratoidea
Family:	†Pachydiscidae; Spath 1922
Genera
	See text

Pachydiscidae is a family of middle and upper Cretaceous ammonites in the superfamily Desmoceratoidea.

Morphology

Pachydiscidae species are moderate to large in size, evolute to rather involute, and vary in section from inflated and depressed to high-whorled and compressed. They are distinguished from the Desmoceratidae by strong ribbing at some growth stage, that normally crosses the venter uninterrupted, and by the tendency to develop strong tuberculation, at least on the umbilical shoulder.^{[citation needed]}

Pachydischidae evolved from Desmoceratidea, during the Lower Cenomanian, about the same time as the Kossmaticeratidae, but lived further into the Maastrichtian, virtually to the end of the Cretaceous.

Genera

Anapachydiscus Yabe and Shimizu, 1926
Baskaniceras Wright and Kennedy, 1984
Canadoceras Spath, 1922
Eopachydiscus Wright, 1955
Eupachydiscus Spath, 1922
Lewesiceras Spath, 1939
Menuites Spath, 1922
Nowakites
Pachydiscus Zittel, 1884
Urakawites Matsumoto, 1955

Distribution

Fossils of Pachydiscidae are found in the Cretaceous marine strata throughout the world, including Angola, Antarctica, Armenia, Australia, Austria, Belgium, Brazil, Bulgaria, Chile, Czech Republic, Denmark, France, Germany, Haiti, India, Jamaica, Japan, Mexico, Netherlands, Nigeria, Oman, Russia, South Africa, Spain, Turkey, United States and Uzbekistan.

References

Mesozoic Ammonoidea. Treatise on Invertebrate Paleontology, Part L (1957), p L377-L380. Geological Society of America.
Paleobiology Database