''Plesioplatecarpus'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

genus of

plioplatecarpine Plioplatecarpinae is a subfamily of mosasaurs, a diverse group of Late Cretaceous marine squamates. Members of the subfamily are informally and collectively known as "plioplatecarpines" and have been recovered from all continents, though the occu ...

mosasaur known from the Late Cretaceous (middle

Coniacian The Coniacian is an age or stage in the geologic timescale. It is a subdivision of the Late Cretaceous Epoch or Upper Cretaceous Series and spans the time between 89.8 ± 1 Ma and 86.3 ± 0.7 Ma (million years ago). The Coniacian is preceded by t ...

to middle Santonian stage) of the northern Gulf of Mexico and the Western Interior Basin of

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

. It was a relatively medium-sized mosasaur, measuring long and weighing .

History

''Plesioplatecarpus'' was originally named by Cope in

1874 Events January–March * January 1 – New York City annexes The Bronx. * January 2 – Ignacio María González becomes head of state of the Dominican Republic for the first time. * January 3 – Third Carlist War &ndas ...

as '' Clidastes planifrons'', and later it was reassigned to '' Platecarpus''. The name ''Plesioplatecarpus'' was erected by Takuya Konishi and Michael W. Caldwell in

2011 File:2011 Events Collage.png, From top left, clockwise: a protester partaking in Occupy Wall Street heralds the beginning of the Occupy movement; protests against Libyan dictator Muammar Gaddafi, who was killed that October; a young man celebrate ...

to incorporate ''Platecarpus planifrons'', which was found to be distinct from '' Platecarpus'' in a phylogenetic analysis. It is known from the holotype AMNH 1491, a nearly complete

skeleton A skeleton is the structural frame that supports the body of an animal. There are several types of skeletons, including the exoskeleton, which is the stable outer shell of an organism, the endoskeleton, which forms the support structure inside ...

. Many other specimens are also referred to this species, including FHSM VP2116 and 2296, UALVP 24240 and 40402 and YPM 40508.

References

Fossil taxa described in 2011 Russellosaurins Mosasaurs of North America Coniacian genus first appearances Santonian genus extinctions {{paleo-lizard-stub