The Platecarpus Collection

Platecarpus was probably the most common genus of mosasaur in the Western Interior Sea during the deposition of the Smoky Hill Chalk in Kansas, and Platecarpus tympaniticus is the species that is found most often. There is some controversy regarding the description of the genus Platecarpus since it includes some diverse, and possibly unrelated forms. They were medium sized animals, reaching about 7 meters (21 feet) in length. Compared to the tylosaurs, Plioplatecarpine mosasaurs had much less robust teeth, suggesting that they fed on smaller (or softer) prey such as small fish and squid. The platecarpine mosasaurs had evolved into the very specialized plioplatecarpine group by the end of the Cretaceous. See Williston 1898 for drawings of the skull of Platecarpus ictericus.

Click on the Thumbnail	Specimen Description	Specimen Number / I.D.
	Left: Three views of a cervical vertebra from the type specimen of Platecarpus tympaniticus Cope 1869, found near Columbus, Mississippi. Right: A fragment of the basio-occipital of the skull of the type specimen of Platecarpus tympaniticus Cope. Note per Konishi and Caldwell (2007), this was the only known specimen of P. tympaniticus. Now (2010) it's the type species.	ANSP 8559 and ANSP 8562; Type specimen, Academy of Natural Sciences of Philadelphia.
	Left: A fragment of a vertebra from the type specimen. Right: Three views of the right quadrate from the type specimen. Note that even though the specimen numbers change, these six bones are all part of the same mosasaur.	ANSP 8558 and ANSP 8487; Type specimen, Academy of Natural Sciences of Philadelphia.
	Left: A portion of the lower jaw of the type specimen. Right: Another cervical vertebra from the type specimen, still in matrix.	ANSP 8484 and ANSP 8488; Type specimen, Academy of Natural Sciences of Philadelphia.
	A picture of a Kansas Platecarpus *tympaniticus* specimen in the Tübinger Museum in Germany. Collected by Charles Sternberg from the Smoky Hill Chalk.	Natural History Museum, University of Tübingen. From von Huene, 1919.
	Platecarpus *tympaniticus* (KUVP 1001) - Nearly complete specimen (missing the tail), that preserves calcified cartilage, including the trachea, skin and scale impressions and stomach contents.	The University of Kansas, Museum of Natural History
	Platecarpus 'coryphaeus' (KUVP 1007), left lateral view of the skull. This specimen was collected by E.P. West in 1890. P. coryphaeus is also a junior synonym of P. *tympaniticus* Cope 1869.	The University of Kansas, Museum of Natural History
	Another left lateral view of the specimen above. Slightly different angle and lighting.	The University of Kansas, Museum of Natural History
	*Platecarpus* *tympaniticus* skull, dorsal view of skull, lower jaws and cervical vertebrae. Specimen collected and prepared by G. F. Sternberg.	Fick Fossil and History Museum, Oakley, KS
	*Platecarpus* *tympaniticus* skull, dorsal view of frontal and parietal	Fick Fossil and History Museum, Oakley, KS
	*Platecarpus* *tympaniticus* skull, dorsal view of premaxilla, and both maxillaries	Fick Fossil and History Museum, Oakley, KS
	*Platecarpus* *tympaniticus* skull and cervical vertebrae, slightly different angle and better lighting.	Fick Fossil and History Museum, Oakley, KS
	*Platecarpus* *tympaniticus* - A nearly complete skeleton from Gove County, KS (Smoky Hill Chalk). This specimen was found by a group of teachers on a field trip.	Emporia State University Johnston Geology Museum, Emporia, Kansas
	NEW 2/2000 Platecarpus **tympaniticus. Additional pictures here: back of skull 1, back of skull 2, and back of skull 3.**	Emporia State University Johntson Geology Museum, Emporia, Kansas
	NEW 2/2000 Platecarpus **tympaniticus. Additional pictures here: skull 2, skull and neck 3, and skull 4.**	Emporia State University Johnston Geology Museum, Emporia, Kansas
	NEW 2/2000 Platecarpus **tympaniticus. Additional pictures here: muzzle, neck and tail vertebrae.**	Emporia State University Johnston Geology Museum, Emporia, Kansas
	*Platecarpus* *tympaniticus*, approximately 6 meters (20 feet) in length, complete skeleton. Although displayed for years in the old museum, this specimen is now in storage. A recent examination showed a number of previously unnoticed pathologies.	Sternberg Museum VP-322
	*Platecarpus* *tympaniticus* skull from the above specimen, dorsal view. NEW 2/2000 - For close-ups of the skull, click on the following: skull1 and skull 2.	Sternberg Museum VP-322
	*Platecarpus* *tympaniticus* skull, dorsal view with lower jaws. This specimen is featured on the Platecarpus webpage. NEW 2/2000 - For close-ups of the skull, go to Page11a.	Sternberg Museum VP-17017
	*NEW 2/2000 Platecarpus ictericus* skull, dorsal view**	Sternberg Museum VP-2077
	NEW 2/2000 Platecarpus planifrons skull, dorsal view. For additional views of the skull, click here: Underside and detail of jaws.	Sternberg Museum VP-2296
	Platecarpus planifrons, skull, dorsal vertebra and limb elements	Sternberg Museum VP-2116
	Platecarpus planifrons, dorsal view of the skull. NEW 2/2000	Sternberg Museum VP-2116
	Platecarpus planifrons, New picture of the dorsal side of the skull.	Sternberg Museum VP-2116
	Platecarpus planifrons, dorsal view of skull elements. This specimen is featured on the another mosasaur discovery webpage. Click here for a picture of the assembled skull.	Sternberg Museum VP-13010
	*Platecarpus* *tympaniticus* , lateral view of premaxilla and left maxilla. This specimen is featured on the another mosasaur discovery webpage. Click here for a webpage describing the reconstruction of this unique mosasaur skull.	Sternberg Museum VP-13010
	*Platecarpus* **tympaniticus, ventral view of muzzle unit (premaxilla and maxillaries). This specimen is featured on the another mosasaur discovery webpage.**	Sternberg Museum VP-13010
	*Platecarpus* **tympaniticus, left and right quadrates. This specimen is featured on the another mosasaur discovery webpage.**	Sternberg Museum VP-13010
	Platecarpus sp. skull, lateral view	The Field Museum of Natural History, Chicago, IL
	Platecarpus planifrons. skull, dorsal view of complete skull, including lower jaws	The University of Kansas, Museum of Natural History
	Platecarpus planifrons. skull, ventral view of complete skull, including lower jaws	The University of Kansas, Museum of Natural History
	An intact and completely articulated Platecarpus *tympaniticus* skull found and prepared by Chuck Bonner. About 24 inches long.	The Keystone Gallery
	A fairly complete Platecarpus *tympaniticus* skull from the Pierre Shale of South Dakota	The Museum of Geology at the South Dakota School of Mines and Technology
	Ectenosaurus clidastoides (FHSM VP_401). This specimen also preserved scale impressions: Scales 1 - Scales 2 - Scales 3	Sternberg Museum VP-401
	Ectenosaurus clidastoides, dorsal cranial view	Sternberg Museum VP-401
	Ectenosaurus clidastoides, slightly different lighting and angle. NEW 2/2000 - For additional pictures of this specimen, click on the following: skull, jaws 1, jaws 2 and front limbs.	Sternberg Museum VP-401
	*A lateral, left side view of a Plioplatecarpus sp. skull from Alabama. This specimen is featured on the Plioplatecarpus webpage.*	Okaloosa Walton Community College, Florida
	A dorsal view of the frontal, parietal and partial post-orbitalfrontals from a recent mosasaur find in Lee County, Mississippi. The remains have been tentatively identified as Plioplatecarpus primaevus, a medium sized mosasaur.	Private collection
	The muzzle of the above specimen, showing several well preserved teeth. This specimen comes from the Bluffport Marl member of the Demopolis Chalk, a formation that was deposited in the Mississippian Embayment.	Private collection
	A dorsal view of the parietal and frontal of the only Plioplatecarpus found to date in Kansas. This picture shows the large parietal foremen which is a characteristic of Plioplatecarpus. Check out the Kansas Plioplatecarpus site for additional pictures	Private collection
	A ventral view of the parietal (left) and frontal (right) of the same specimen. Although these remains were partially prepared, the invasion of selenite crystals into the bone has already destroyed much of the detail of the surface	Private collection
	The braincase of this Plioplatecarpus specimen, from above (the basio-occipital and basio- splenoid bones that form the base of the braincase (center) are flanked by the left and right pro-otics.	Private collection
	Pieces of the lower jaws of the Plioplatecarpus sp. specimen from the upper portion of the Sharon Springs member of the Pierre Shale, Logan County, KS. The teeth were still in surprising good shape for a 'shale fossil'.	Private collection
	An articulated series of four cervical vertebrae.	Private collection
	From left to right, an exterior view of the left quadrate, and an interior view of the right quadrate of Plioplatecarpus. Note the stapedial pit on the inside of the right quadrate. This structure is useful in determining the species of the mosasaur	Private collection
	Two pathological dorsal vertebrae (fused) showing evidence of a healed spinal injury or disease that must have been painful, and may have seriously hindered the swimming ability of this mosasaur.	Private collection
	A nicely preserved dorsal vertebrae. This specimen is of late Campanian age and is comparable with material from the lower Pierre Shale of Kansas and S. Dakota.	Private collection
	Head on view of the cast of a large Plioplatecarpus skull (UNO 8611-2). The original specimen was prepared and described by David Burnham in his Master's thesis at the University of New Orleans, 1991.	Exhibited in the Tate Geological Museum, Casper, WY
	Right side view of the same skull, showing the unusually large eyes and shorter snout that are typical of Plioplatecarpus. The original specimen was found in the Demopolis Chalk of western Alabama.	Exhibited in the Tate Geological Museum, Casper, WY
	Another right side view of the same skull Several drawings of this nearly complete skull by David Burnham are shown on the Plioplatecarpus webpage.	Exhibited in the Tate Geological Museum, Casper, WY
	Plioplatecarpus was one of several mosasaurs that were still around at the end the Cretaceous and occur somewhat later in the geologic record than the mosasaurs from the Smoky Hill Chalk.	Exhibited in the Tate Geological Museum, Casper, WY
	A view of the back of the skull, showing the occipital condyle where the first vertebra is attached, and the opening for the spinal cord into the braincase.	Exhibited in the Tate Geological Museum, Casper, WY
	Another rear view of the skull, showing the occipital condyle, the size of the braincase, and the open framework of the skull. In life, these openings were filled with the strong muscles that closed the jaw.	Exhibited in the Tate Geological Museum, Casper, WY
	A view of the top of the skull (and the suture between the parietal and frontal bones) showing the large parietal foremen that is typical of plioplatecarpines. The function of this opening in mosasaurs is not known.	Exhibited in the Tate Geological Museum, Casper, WY
	*The snout, showing the suture between the premaxilla bone (top) and the right maxilla. The nasal openings are relatively larger in Plioplatecarpus* compared to other mosasaurs.**	Exhibited in the Tate Geological Museum, Casper, WY
	The orbit of the right eye, formed by the jugal bone below and behind, the post orbital frontal above, the frontal, and the prefrontal. The scratches over the eye appear to be bite marks, possibly caused by scavenging.	Exhibited in the Tate Geological Museum, Casper, WY
	A view of the right quadrate. Some damage to the joint at the back of the right lower jaw is apparent.	Exhibited in the Tate Geological Museum, Casper, WY
	*Possibly a new species of Plioplatecarpus from North Dakota, this animal was larger than previous known specimens. For more information see the North Dakota Plioplatecarpus* page.**	Soon to be on exhibit in the North Dakota Heritage Center (ND97-115.1)
	A left side view of the premaxilla or muzzle of the mosasaur. Scale is in centimeters (cm). Pictures courtesy of John Campbell, North Dakota Geological Survey.	Soon to be on exhibit in the North Dakota Heritage Center (ND97-115.1)
	A dorsal view of the frontal and parietal bones that comprise the top of the skull.	Soon to be on exhibit in the North Dakota Heritage Center (ND97-115.1)
	A lateral and medial view of the left quadrate of the mosasaur. Pictures courtesy of John Campbell, North Dakota Geological Survey.	Soon to be on exhibit in the North Dakota Heritage Center (ND97-115.1)
	Bite marks on the right jugal (lower and rear part of the orbit of the eye) which indicate scavenging of the carcass by sharks.	Soon to be on exhibit in the North Dakota Heritage Center (ND97-115.1)
	*The fragmentary skull of a very small mosasaur (possibly a Platecarpus* unborn fetus or recently born neonate) from the lower Smoky Hill Chalk of Kansas.**	Sternberg Museum VP-14845
	An updated photograph of the above specimen (after donation).	Sternberg Museum VP-14845

Continue to the:

	*The Clidastes* Collection**
	*The Tylosaurus* Collection**
	*The Mosasaurus* and other Mosasaurs Collection**

CREDITS: Many of the pictures from the Sternberg Memorial Museum, Fort Hays State University, Hays, Kansas, were scanned from Bruce Schumacher's Master's Thesis, "Biostratigraphy of Mosasauridae (Squamata, Varanoidea) from the Smoky Hill Chalk Member, Niobrara Chalk (Upper Cretaceous) of Western Kansas" (1993), and used with his permission.