7 miles southeast of Castle Rock (Cretaceous to of the United States)

Also known as Clidastes planifrons type

Where: Trego County, Kansas (38.8° N, 100.1° W: paleocoordinates 41.6° N, 66.4° W)

• coordinate based on nearby landmark

• small collection-level geographic resolution

When: Smoky Hill Chalk Member (Niobrara Formation), Late/Upper Coniacian to Late/Upper Coniacian (89.3 - 83.5 Ma)

• lower part of member

• bed-level stratigraphic resolution

Environment/lithology: marine; chalk

Size class: macrofossils

Collected by B. F. Mudge in 1873; reposited in the AMNH

Primary reference: E. D. Cope. 1874. Review of the Vertebrata of the Cretaceous Period found west of the Mississippi River. Bulletin of the United States Geological and Geographical Survey of the Territories, First Series 2:3-48 [M. Carrano/M. Carrano/M. Carrano]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 123571: authorized by Philip Mannion, entered by Philip Mannion on 26.01.2012

Creative Commons license: CC BY (attribution)

Taxonomic list

 Squamata - Mosasauridae
"Clidastes planifrons n. sp." = Platecarpus planifrons
"Clidastes planifrons n. sp." = Platecarpus planifrons Cope 1874 mosasaur
Holotype - AMNH 1491, incomplete cranial and postcranial elements, consisting of frontal, right pterygoid, quadrates, parietal, left postorbitofrontal, left squamosal, left splenial, left angular, left surangular, left coronoid, basisphenoid-basioccipital, fifteen anterior vertebrae including atlas-axis, and other miscellaneous bone fragments