Genus: Plesioplatecarpus KONISHI & CALDWELL, 2011
Etymology: Latin, plesio, "near" + Platecarpus; referring to its close evolutionary affinity to the more-derived Platecarpus.

Species: planifrons (COPE, 1874) KONISHI & CALDWELL, 2011
Etymology:
= Clidastes planifrons COPE, 1874
= Platecarpus planifrons (COPE, 1874) WILLISTON, 1898

Holotype: AMNH 1491

Locality: 7 miles southeast ("Southwest" according to the AMNH specimen lable, which is likely mistaken: KONISHI& CALDWELL, 2007 Everhart , pers. comm.) of Castle Rock , Trego County, Kansas.

Horizon: Lower part of the Smoky Hill Chalk Member, Niobrara Chalk Formation.

Biostratigraphy:

Age: Upper Coniacian Stage, Lower most Senonian Subepoch-Santonian Stage, Lower Senonian Subepoch, Lower Gulf Epoch, Early Late Cretaceous.

Material: Fragmentary skull, cervical and dorsal vertebrae and fragments of other elements.

Referred material:

BELL, 1997

KU 14349, 75037, 84853:

AMNH 1511:

FHM 2116, 2181:

MCZ 1610, 1614:

YPM 3971, 40409, 40434, 40439, 40506:

 

BELL & BARNES, 2007

Locality: Near Terlingua, Big Bend Region, Brewster County, Texas.

Horizon: Upper San Vicente Member, Boquillas Formation.

Biostratigraphy:

Age: Upper Coniacian Stage, Lowermost Senonian subepoch, Gulf Epoch, Late Cretaceous.

Material:

MRM KP-M-19: Fragmentary skeleton.

Note: Has fragmentary fish remains in its stomach region.

Numbr: Not given: Fragmentary remains of two size classes.

Note: Found in the stomach region of Tylosaurus nepaeolicus (MRM KB-M-3) along with teeth of the shark Ptychodus mortoni.

 

KONISHI, 2007, 2008

Locality: Montgomery County, Alabama.

Horizon: Tombigbee Sand Member, Eutaw Formation, Selma Group.

Biostratigraphy:

Age: Middle Santonian Stage, Lower Senionian Subepoch, Lower Gulf Epoch, Late Cretaceous.

Material:

MSC 9515: Isolated frontal missing premaxillary porcess, left posterolateral ala, and pair of posteromedian flanges postmortem.

 

 

KONISHI & CALDWELL, 2007

Locality: On the west side of Sand Creek, Smoky Hill River, Southeast corner of Gove County, Kansas.

Horizon: Lower part of the Smoky Hill Chalk Member, Niobrara Chalk Formation.

Biostratigraphy:

Age: Upper Coniacian Stage, Lower most Senonian Subepoch-Santonian Stage, Lower Senonian Subepoch, Lower Gulf Epoch, Early Late Cretaceous.

Material:

UALVP 24240: Articulated skull, lower jaws, atlas, and axis.

UALVP 49492: Disarticulated skull and lower jaw bones with 4 anterior cervical vertebrae.

 

Locality: Trego County, Kansas.

Horizon: Lower part of the Smoky Hill Chalk Member, Niobrara Chalk Formation.

Biostratigraphy:

Age: Upper Coniacian Stage, Lower most Senonian Subepoch-Santonian Stage, Lower Senonian Subepoch, Lower Gulf Epoch, Early Late Cretaceous.

Material: YPM 40508: Disarticulated and fragmentary cranial and postcranial material including premaxilla, left maxilla, nearly complete frontal, right jugal, ectopterygoid (?), pterygoids, left squamosal, left quadrate, lower jaw fragments, several vertebrae and phalanges.

YPM 40508: Frontal after KONISHI & CALDWELL, 2007.

SHELDON, 1996

Locality: Logan County, Kansas.

Horizon: Niobrara Formation.

Biostratigraphy:

Age: Late Cretaceous.

Material:

YPM 1427: Adult.

 

Locality: Trego County, Kansas.

Horizon: Niobrara Formation.

Biostratigraphy:

Age: Late Cretaceous.

Material:

YPM 40451: Late juvenile.

YPM 40452, 40458: Adult.

YPM 40453: Subadult.

 

Locality: Ellis County, Kansas.

Horizon: Niobrara Formation.

Biostratigraphy:

Age: Late Cretaceous.

Material:

YPM 3994: Early juvenile.

YPM 40434, 3971: Late juvenile.

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