page_title: Platecarpus
section_title: Taxonomic history
hierarchical_section_title: Platecarpus / History / Taxonomic history
caption_attribution_description: Naturhistorisches Museum Wien
context_page_description: Platecarpus is an extinct genus of aquatic lizards belonging to the mosasaur family, living around 84–81 million years ago during the middle Santonian to early Campanian, of the Late Cretaceous period. Fossils have been found in the United States and a possible specimen in Belgium and Africa. A well-preserved specimen of Platecarpus shows that it fed on moderate-sized fish, and it has been hypothesized to have fed on squid, and ammonites as well. Like other mosasaurs, it was initially thought to have swum in an eel-like fashion, although another study suggests that it swam more like modern sharks. An exceptionally well-preserved specimen of P. tympaniticus known as LACM 128319 shows skin impressions, pigments around the nostrils, bronchial tubes, and the presence of a high-profile tail fluke, showing that it and other mosasaurs did not necessarily have an eel-like swimming method, but were more powerful, fast swimmers. It is held in the Natural History Museum of Los Angeles County.
context_section_description: Platecarpus was often regarded as the most common genus of mosasaur in the Western Interior Sea during the deposition of the Smoky Hill Chalk in Kansas, and Platecarpus ictericus was regarded as the most commonly occurring species. However, scientists now consider it to be of the paraphyletic genus. Therefore, some species were reassigned to their own genera. The type specimen of Platecarpus planiforns was discovered by Professor B. F. Mudge and was classified by Edward Drinker Cope as Clidastes planiforns. In 1898, on further analysis of the remains, it was determined that the mosasaur be placed in the genus Platecarpus. The type specimen underwent another taxonomic review in 1967, when paleontologist Dale Russell determined that the remains were too fragmentary to place within any genus, and deemed it a specimen of "uncertain taxonomic position". A 2006 discovery in the Smoky Hill Chalk of Kansas re-affirmed this position with the discovery a complete fossilized skull being unearthed. In 2011, a new generic name, Plesioplatecarpus, was erected by Takuya Konishi and Michael W. Caldwell to incorporate P. planifrons, which they found was distinct from Platecarpus in a phylogenetic analysis. In 1994, Angolasaurus was synonymized with this genus. However, many recent studies re-validate this genus. Furthermore, Platecarpus is considered monotypic, as P. coryphaeus and P. ictericus were synonymized with its type species, P. tympaniticus.
  The cladogram below follows the most resolved topology from a 2011 analysis by paleontologists Takuya Konishi and Michael W. Caldwell.
caption: Skeleton in Naturhistorisches Museum Wien
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