| Polyptychodon | |
|---|---|
 | |
| P. interruptus jaw with tooth | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Superorder: | †Sauropterygia |
| Order: | †Plesiosauria |
| Suborder: | †Pliosauroidea |
| Family: | †Pliosauridae |
| Clade: | †Thalassophonea |
| Subfamily: | †Brachaucheninae |
| Genus: | †Polyptychodon Owen, 1841[1] |
| Type species | |
| †Polyptychodon interruptus Owen, 1841[1] | |
| Other species | |
Polyptychodon (meaning 'many-folded tooth') is agenus ofpliosaurid found in Middle-Late Cretaceous marine deposits in southern England, France and Argentina. It has been considered anomen dubium in a 2016 review.[2]
Thetype species,P. interruptus is known from an isolated tooth from the Late CretaceousChalk Group of southernEngland.[1] Owen described a second nominal species of the genus,P. continuus, from an isolated tooth collected in theHythe Formation ofMaidstone,Kent. (The macronarian sauropodDinodocus was mistakenly thought to be conspecific withP. continuus before it was correctly recognized as a dinosaur and not a plesiosaur.)
Numerous pliosaurid teeth and vertebrae from England and eastern France have been previously assigned toPolyptychodon, including isolated vertebrae from France which were misidentified as a sauropod.[3] Comparison between Albian-age isolated vertebrae from marine deposits in France andKronosaurus suggested a size of approximately 7 metres (23 ft) for aPolyptychodon-like brachaucheniine pliosaurid.[3] However, a 2016 re-evaluation foundPolyptychodon and its types species to be dubious, and that numerous remains from the Chalk Group in England that had been referred to the genus most likely represent different species of plesiosaurs, with some teeth possibly being referable toPolycotylidae.[2] Similar fossils of pliosaurs were found also inCzech Republic.[4]
The speciesPolyptychodon patagonicus (Ameghino, 1893), based on crocodile teeth discovered inArgentina, shares the same genus name. According to a 2010 study,P. patagonicus is anomen vanum and anomen dubium.[5]
Polyptychodon hudsoni (holotytpe, SMU 60313) was described from theTuronian-ageEagle Ford Formation of Dallas,Texas.[6][7] It probably belongs to a different genus.[2][8]
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