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Copyright 2000-2009 by Mike Everhart

Page updated 02/14/2009


LEFT: Drawing by N. L. Mohler, Copyright by the University of  Nebraska State Museum, used with permission. Note that elasmosaurs could not lift their head and neck out of the water as shown here..

In 1970, Sam Welles published a brief note entitled "The Longest Neck in the Ocean" in the Museum Notes of the University of Nebraska State Museum. The paper was about the discovery of a very large elasmosaur in the Graneros Shale of eastern Nebraska in 1964.  The specimen was found essentially complete although some caudal vertebrae had eroded out and been lost prior to its discovery. The elasmosaur (Thalassomedon haningtoni; UNSM 50132) was reported to be about 41 feet long... almost as long as the Elasmosaurus platyurus described by Cope (1868). Surprisingly, it had fewer cervical vertebrae than E. platyurus (63 vs. 71). The head, and most of the neck of this specimen is on exhibit in the floor of the Cretaceous exhibit at the University of Nebraska State Museum, Lincoln, NE.  About 80 gastroliths are also on display.


50132-1a.jpg (4373 bytes) A slightly foreshortened view of the skull of UNSM 50132 taken with flash.  The fossil is under a thick piece of Plexiglas in a darkened room, so photographing it is a challenge.
50132-2a.jpg (5135 bytes) A better view of the skull, using the available fluorescent lighting.  This skull is about 20 inches long, slightly larger than the specimen of Thalassomedon haningtoni (DMNH 1588) at the Denver Museum of Nature and Science. Also you can compare it to a specimen of Styxosaurus snowii at the University of Kansas Museum of Natural History and the reconstructed skull of Alzadasaurus pembertoni (now Styxosaurus snowii) at the South Dakota School of Mines and Technology. Note how the jaws are hinged at the extreme rear part of the skull, allowing the jaws to be opened like they are shown in this detail from a picture by Charles R. Knight.
50132-0a.jpg (4731 bytes) A closer view of the anterior portion of the skull. Note the slender, interlocking teeth, well adapted for catching small fish, squid and other soft-bodied prey.
50132-3a.jpg (5440 bytes) An oblique view of the head and anterior portion of the neck.

Click here for a page on the anatomy of the plesiosaur skull.

50132-5a.jpg (5645 bytes) Another view of the skull (taken with a film camera instead of a digital).
50132-4a.jpg (4945 bytes) A picture of several gastroliths from UNSM 50132 still in the original jacket.  Two pictures of some of the gastroliths on exhibit are here and here.  More information about gastroliths in plesiosaurs here.

Here's a more recent (2003) story about the discovery of another elasmosaur in Nebraska.


Carpenter, K., 1999. Revision of North American elasmosaurs from the Cretaceous of the Western Interior, Paludicola, 2(2):148-173

Cicimurri, D. J. and M. J. Everhart, 2001. An elasmosaur with stomach contents and gastroliths from the Pierre Shale (late Cretaceous) of
Kansas. Kansas Acad. Sci. Trans 104(3-4):129-143.

Everhart, M. J., 2000. Gastroliths associated with plesiosaur remains in the Sharon Springs Member of the Pierre Shale (Late Cretaceous),
Western Kansas. Kansas Acad. Sci. Trans. 103(1-2):58-69.

Everhart, M. J., 2001. Revisions to the Biostratigraphy of the Mosasauridae (Squamata) in the Smoky Hill Chalk Member of the Niobrara Chalk (Late Cretaceous) of Kansas. Kansas Acad. Sci. Trans 104(1-2):56-75.

Everhart, M. J., 2002. Where the Elasmosaurs roam...... Prehistoric Times. 53:24-27.

Massare, J. A. 1987. Tooth morphology and prey preference of Mesozoic marine reptiles, Jour. Vert. Paleon. 7(2):121-137

Schultz, C. B., 1965. The story of a Nebraska sea serpent. Museum Notes, University of Nebraska State Museum. 27:1-3.

Shimada, K., 1997. Paleoecological relationships of the late Cretaceous lamniform shark, Cretoxyrhina mantelli (Agassiz). Journ.
Paleon. 71(5):926-933.

Storrs, G. W., 1999. An examination of Plesiosauria (Diapsida: Sauropterygia) from the Niobrara Chalk (Upper Cretaceous) of central North
America, Univ. Kansas Paleon. Contri. (N.S.), No. 11, 15 pp.

Welles, S. P., 1970. The longest neck in the ocean. Museum Notes, University of Nebraska State Museum, 43:1-2