Pachydiscidae
Temporal range: Cenomanian - Maastrichtian
Eupachydiscus isculensis from Cretaceous – Bergamo (Italy)
Scientific classification Edit this 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.

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

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

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