| Named By: | Louis Agassiz in 1835 |
| Time Period: | late Cretaceous, 112-70 Ma |
| Location: | Known mostly from Europe, Canada - Saskatchewan, and the USA - Alabama, Colorado, Georgia, Kansas, New Mexico and South Dakota. Similar teeth are also known from other parts of the world hinting at a possibly cosmopolitan distribution |
| Size: | Largest species such as P. mortoni estimated at 10 meters long |
| Diet: | Durophagus (shellfish/crustaceans) |
| Fossil(s): | Mostly teeth, but scales, vertebra and a jawbone fragment are also known |
| Classification: | | Chordata | Chondrichthyes | Elasmobranchii | Selachimorpha | Hybodontoidea | Ptychodontidae | |
Ptychodus is a genus of extinct hybodontiform sharks. As well as a genus of durophagous (shell-crushing) sharks from the Late Cretaceous. Fossils of Ptychodus teeth are found in plenty in many of the Late Cretaceous marine sediments. There are many species among the Ptychodus that have been uncovered on all the continents around the globe. Such species are Ptychodus mortoni, P. decurrens, P. marginalis, P. mammillaris, P. rugosus and P. latissimus to name a few. They died out approximately 85 million years ago in the Western Interior Sea, where a majority of them were found. A recent publication found that Ptychodus are classified as neoselachian versus hybodont or batoid.