The Mosasaurus and Other Mosasaurs Collection

In this section, I have placed pictures of some of the remaining genera of mosasaurs. Mosasaurus occurs later in the deposition of the Pierre Shale (early Campanian time). It was a very large mosasaur, reaching lengths of greater than 12 meters. Mosasaurus was probably the first mosasaur found in America. As early as 1804, the Lewis and Clarke Expedition found the remains of a large 'fish' on an island in the Missouri River near the big bend in South Dakota. Part of the specimen was sent back to Washington where it was subsequently lost. Judging from a description in the journals of the expedition, it was probably the remains of a large mosasaur from the Pierre Shale (See Harlan, 1834). In the 1830s, a government Indian Agent (Major Benjamin O'Fallon) obtained another specimen in about the same area of South Dakota, and took it back to his home in St. Louis where it was exhibited in his garden. It was later acquired by Prince Maximilian von Wied during his expedition to the American West and shipped to Germany. The remains were then examined and described by Dr. A. Goldfuss as Mosasaurus Maximiliani. The specimen is still in the collection of the Goldfuss Museum in Bonn, Germany. See Williston's (1898) drawings of a Mosasaurus skull HERE.

Click on the Thumbnail	Specimen Description	Specimen Number / I.D.
	Mosasaurus missouriensis (horridus Williston), lateral view of the right side of a complete skull, Pierre Shale, South Dakota. This skull is about one meter (39 inches) long	The University of Kansas, KUVP 1034, Museum of Natural History
	Mosasaurus missouriensis (horridus Williston), lateral view of the left side of a complete skull, Pierre Shale, South Dakota. Originally a new species named by Williston, the name was later changed.	The University of Kansas, Museum of Natural History, KUVP 1034
	Mosasaurus missouriensis (horridus Williston), dorsal -lateral view of the left rear quadrant of a complete skull, Pierre Shale, South Dakota	The University of Kansas, Museum of Natural History, KUVP 1034
	Mosasaurus missouriensis (horridus Williston), dorsal -lateral view of the left rear quadrant of a complete skull, Pierre Shale, South Dakota. Note location of quadrate connecting jaw to skull.	The University of Kansas, Museum of Natural History
	Mosasaurus missouriensis (horridus Williston), view of the back of a complete skull, Pierre Shale, South Dakota. Large oval bone at center of picture is the right quadrate.	The University of Kansas, Museum of Natural History
	Mosasaurus sp., lateral view of the right side of the skull. Bear Paw Shale Fm., Montana. The story of the discovery and collecting of this specimen is told in John Horner's book, Living with Dinosaurs	Museum of the Rockies, Montana State University, Bozeman, Montana MOR-006
	Left side of skull. "Large mosasaur with both scapula-coracoids, several cervical and dorsal vertebrae, including entire atlas-axis complex, several ribs, one or two paddles, interclavicle, both pubes and complete skull"	Photo used with permission, Museum of the Rockies, Montana State University, Bozeman, MT. Do not copy without permission.
	Back of skull of MOR-006, showing large openings that enclosed the large muscles that closed the lower jaw.	Photo used with permission, Museum of the Rockies, Montana State University, Bozeman, MT. Do not copy without permission.
	*Front limb of MOR-006. Based on the shapes of various bones in this paddle, it is most likely that this specimen is a Mosasaurus conodon.*	Photo used with permission, Museum of the Rockies, Montana State University, Bozeman, MT. Do not copy without permission.
	*A reconstruction of a thirty foot long Mosasaurus conodon* (SDSMT-452) skeleton from the Pierre Shale of South Dakota, approximately 75 million years old.**	The Museum of Geology at the South Dakota School of Mines and Technology, Rapid City, South Dakota
	A closer view of the left side of the skull of SDSMT-452. To see more pictures of this specimen, CLICK HERE.	The Museum of Geology at the South Dakota School of Mines and Technology, Rapid City, South Dakota
	Globidens dakotensis, ventral view of skull showing unusual round teeth, Pierre Shale, South Dakota	The Field Museum of Natural History, Chicago, Illinois
	Globidens sp. lateral view of right dentary, from the Pierre Shale of Kansas. This specimen is featured on the Globidens webpage. Click here for a drawing of Globidens by Russell Hawley.	FHSM VP 13828; Sternberg Museum of Natural History, Hays, KS.
	Globidens sp. lateral view of the anterior portion of the right dentary, from the Pierre Shale of Kansas. This specimen is featured on the Globidens webpage.	FHSM VP 13828; Sternberg Museum of Natural History, Hays, KS.
	A fragment of the upper jaw of an unidentified mosasaur from the Saratoga chalk of southwestern Arkansas (near Columbus, AR).	This photograph was provided courtesy of the Arkansas State University Museum at Jonesboro, Arkansas
	A close-up of two of the remaining teeth. At the time, southwestern Arkansas was ocean front property along the Gulf Coast of eastern North America.	This photograph was provided courtesy of the Arkansas State University Museum at Jonesboro, Arkansas
	Four views of a single dorsal vertebra from the Arkansas specimen. In mosasaurs, the rounded end of the vertebrae point away from the head.	This photograph was provided courtesy of the Arkansas State University Museum at Jonesboro, Arkansas
	*Five of the vertebrae from the Arkansas specimen. Although there is little diagnostic material available, these bones probably came from a Mosasaurus* or Plioplatecarpus.**	This photograph was provided courtesy of the Arkansas State University Museum at Jonesboro, Arkansas
	Ventral view of a Prognathodon overtoni skull (SDSMT- 3393) from the Pierre Shale of South Dakota. Note the two extra rows of teeth on the roof of the mouth (pterygoid bones). See a web page about this specimen here.	The Museum of Geology at the South Dakota School of Mines and Technology, Rapid City. South Dakota
	This photo (courtesy of Lynn Harrell, Jr.) shows the remains of a Prognathodon sp. from the Coon Creek Member of the Ripley Formation (late Cretaceous in western Tennessee. This specimen was found in 1989, and identified by Gordon Bell.	Pink Palace Museum, Memphis, Tennessee. See also the Coon Creek Science Center.
	A close-up of the frontal of the Tennessee Prognathodon sp. specimen. The Coon Creek formation was deposited in a shallow, near-shore environment as a part of the Mississippian Embayment during late Cretaceous time. (Photo courtesy of Lynn Harrell, Jr.)	Pink Palace Museum, Memphis, Tennessee. See also the Coon Creek Science Center.
	*The lower jaws of Prognathodon sp. Compare these with the lower jaws of a similar specimen from the Pierre Shale of South Dakota. (Photo courtesy of Lynn Harrell, Jr.)*	Pink Palace Museum, Memphis, Tennessee. See also the Coon Creek Science Center.
	This jumble of bones in includes parts of the mosasaur's skull and vertebrae. The two white objects are clam shells, which are preserved in great abundance in the Coon Creek member of the Ripley Formation. (Photo courtesy of Lynn Harrell, Jr.)	Pink Palace Museum, Memphis, Tennessee. See also the Coon Creek Science Center.
	This is a picture of a large mosasaur vertebra as found in the Coon Creek Formation at the Coon Creek Science Center. The vertebrae is a part of a recently discovered set of mosasaur remains. (Photo courtesy of Vicky Goodrum).	Pink Palace Museum, Memphis, Tennessee. See also the Coon Creek Science Center.
	*A cast of the skull of Plotosaurus bennisoni, an unusual mosasaur from California. The original specimen (UC V3718 / 32778) is at the University of California.*	Natural History Museum, Sierra College, Rocklin CA.
	A side view of the skull ... notice the large opening for the eye. This is somewhat larger than most other mosasaurs.	Natural History Museum, Sierra College, Rocklin CA.
	A top view of the front of the skull.	Natural History Museum, Sierra College, Rocklin CA.
	A lateral view of the rear, right side of the skull.	Natural History Museum, Sierra College, Rocklin CA.
	A view of the back of the skull showing the occipital condyle where the atlas-axis vertebra is attached.	Natural History Museum, Sierra College, Rocklin CA.
	A closer look at the back of the skull. A figure adapted from Camp (1942) of the complete skeleton of UC V3718 / 32778 is shown HERE.	Natural History Museum, Sierra College, Rocklin CA.
	LEFT: A drawing of the skull of Plotosaurus bennisoni (Camp) in dorsal and left lateral view, adapted from Piveteau, J. (Ed.) (1952-1969). Traité de Paléontologie, Tome V. (Scan provided by Amin Khaleghparast, July, 2012). RIGHT: The original figure by Camp (1942, fig. 1)

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	*The Clidastes* Collection**
	*The Platecarpus* Collection**
	*The Tylosaurus* Collection**

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Mosasaurs: Last of the great Marine Reptiles