Trinacromerum bentonianum Cragin 1888 ~ ~ KUVP 5070 - A polycotylid from the "Fort Benton" of Kansas   Copyright © 2008-2010 by Mike Everhart Created 03/11/2008 - Last updated 10/28/2010     LEFT:  A Trinacromerum bentonianum plesiosaur swims along the bottom of the seas covering Kansas during Turonian time.   Copyright © Dan Varner; used with permission of  Dan Varner

	LEFT: The skull Trinacromerum bentonianum (KUVP-5070) in right lateral view. This specimen was originally described in 1944 by Elmer Riggs and named Trinacromerum "willistoni" in honor of  S. W. Williston, but the name is considered to be a junior synonym of T. bentonianum (Carpenter, 1996).
	LEFT: The skull Trinacromerum bentonianum (KUVP-5070) in left lateral view.  Riggs (1944) noted that the specimen as from ten feet below the Jetmore Chalk Member, in the Hartland Shale Member, Greenhorn Limestone
	LEFT: The distal end of the jaws in left lateral view.
	LEFT: The center portion of the skull and lower jaws in right lateral view.
	LEFT: The articulation of the quadrate bone of the skull with the articular of lower jaw, in right lateral view.

REFERENCES

Adams, D. A. 1977. Trinacromerum bonneri, a new polycotylid plesiosaur from the Pierre Shale of South Dakota and Wyoming.  Unpublished Masters thesis, University of Kansas, 97 pages.

Adams, D. A. 1997. Trinacromerum bonneri, new species, last and fastest pliosaur of the Western Interior Seaway. Texas Journal of Science, 49(3):179-198.

Bonner, O. W. 1964. An osteological study of Nyctosaurus and Trinacromerum with a description of a new species of Nyctosaurus, Unpub. Masters Thesis, Fort Hays State University, 63 pages.

Carpenter, K. 1996. A Review of short-necked plesiosaurs from the Cretaceous of the western interior, North America, Neues Jahrbuch für Geologie und Paläeontologie Abhandlungen, (Stuttgart) 201(2):259-287.

Carpenter, K. 1997. Comparative cranial anatomy of two North American Cretaceous plesiosaurs, pp. 191-216, In Calloway, J. M. and E. L. Nicholls, (eds.), Ancient Marine Reptiles, Academic Press.

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.

Cope, E. D. 1869. [Remarks on fossil reptiles, Clidastes propython, Polycotylus latipinnis, Ornithotarsus immanis.]. Proceedings of the American Philosophical Society xi p. 117. (meeting of June 18, 1869)

Cope, E. D. 1875. The Vertebrata of the Cretaceous formations of the West. Report, U. S. Geological Survey Territories (Hayden). 2:302 p, 57 pls.

Cragin, F. W. 1888. Preliminary description of a new or little known saurian from the Benton of Kansas, American Geologist 2:404-407.

Cragin, F. W. 1891. New observations on the genus Trinacromerum. American Geologist 8:171-174.

Druckenmiller, P. S. 1998. Osteology and relationships of a plesiosaur (Sauropterygia) from the Thermopolis Shale (Lower Cretaceous) of Montana. Unpublished Masters Thesis, Montana State University.

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. 2003. First records of plesiosaur remains in the lower Smoky Hill Chalk Member (Upper Coniacian) of the Niobrara Formation in western Kansas. Kansas Academy of Science, Transactions 106(3-4):139-148.

Everhart, M. J. 2004. Plesiosaurs as the food of mosasaurs; new data on the stomach contents of a Tylosaurus proriger (Squamata; Mosasauridae) from the  Niobrara Formation of western Kansas. The Mosasaur 7:41-46.

Everhart, M. J.  2004. New data regarding the skull of Dolichorhynchops osborni (Plesiosauroidea: Polycotylidae) from rediscovered photos of the Harvard Museum of Comparative Zoology specimen. Paludicola 4(3):74-80.

Everhart, M. J. 2005. Bite marks on an elasmosaur (Sauropterygia; Plesiosauria) paddle from the Niobrara Chalk (Upper Cretaceous) as probable evidence of feeding by the lamniform shark, Cretoxyrhina mantelli. PalArch, Vertebrate paleontology 2(2): 14-24.

Everhart, Michael J. 2005. Oceans of Kansas - A Natural History of the Western Interior Sea. Indiana University Press, 320 pp. ISBN: 0253345472

Everhart, M. J. 2007. Sea Monsters: Prehistoric Creatures of the Deep. National Geographic, 192 p.     ISBN-13: 978-1426200854

Knight, W. C. 1898. Some new Jurassic vertebrates   from Wyoming. Amer. Jour. Sci., ser. 4, 5(29):378-380. [Megalneusaurus rex, a giant pliosaurid]

Lane, H. H. 1946. A survey of the fossil vertebrates of Kansas, Part III, The Reptiles, Kansas Academy Science, Transactions 49(3):289-332, 7 figs.

Lingham-Soliar, T. 2000. Plesiosaur locomotion: Is the four-wing problem real or merely an atheoretical exercise? N. Jb. Geol. Paläont. Abh. 217:45-87.

Lucas, S. G. 1994. Late Cretaceous pliosaurs (Eurapsida: Plesiosauroida) from the Black Mesa Basin, Arizona, U. S. A. Journal of the Arizona-Nevada Academy of Science 28(1/2):41-45.

Martin, J. E. and L. E. Kennedy. 1988. A plesiosaur from the late Cretaceous (Campanian) Pierre Shale of South Dakota: A preliminary report, Proc. S.D. Acad. Sci., 67:76-79.

Martin, J. E. and A. J. Kihm. 1988. Two unusual stratigraphic occurrences of plesiosaurs from late Cretaceous formations of the Black Hills area, Wyoming and South Dakota. Proc. S.D. Acad. Sci., 67:73-75.

Moodie, R. L. 1911. An embryonic plesiosaurian propodial, Trans. Kansas Acad. Sci. 23:95-101, 9 figs, 1 pl.

O'Keefe, F. R. 1999. Phylogeny and convergence in the Plesiosauria. Journ. Vert. Paleon. 19(3):67A. (abstract)

O'Keefe, F. R. 2001. A cladistic analysis and taxonomic revision of the Plesiosauria (Reptilia: Sauropterygia). Acta Zool. Fennica 213:1-63.

O'Keefe, F. R.  2001. Ecomorphology of plesiosaur flipper geometry. J. Evol. Biol. 14:987-991.

O'Keefe, F. R. 2002. The evolution of plesiosaur and pliosaur morphotypes in the Plesiosauria (Reptilia: Sauropterygia). Paleobiology 28(1):101-112.

O'Keefe, F. R. 2004. On the cranial anatomy of the polycotylid plesiosaurs, including new material of Polycotylus latipinnis Cope, from Alabama. Journal of Vertebrate Paleontology 24(2):326-340.

O'Keefe, F. R. 2008. Cranial anatomy and taxonomy of Dolichorhynchops bonneri new combination, a polycotylid plesiosaur from the Pierre Shale of Wyoming and South Dakota. Journal of Vertebrate Paleontology 28(3): 664-676.

Riess, J. and E. Frey. 1991. The evolution of underwater flight and the locomotion of plesiosaurs. pp. 131-144, In Rayner, J. M. V. and R. J.   Wooton (eds.), Biomechanics in evolution. Cambridge Univ. Press.

Riggs, E. S. 1944. A new polycotylid plesiosaur. University of Kansas Science Bulletin 30:77-87.

Robinson, J. A. 1975. The locomotion of plesiosaurs, N. Jb. Geol. Paläont. Abh., 149, 3:286-332.

Russell, D. A. 1967. Cretaceous vertebrates from the Anderson River N. W. T. Canadian Journal of Earth Sciences 4:21-38.

Russell, L. S. 1935. A plesiosaur from the Upper Cretaceous of Manitoba. Jour. Paleon. 9:385-389.

Sato, T. and K. Tanabe. 1998. Cretaceous plesiosaurs ate ammonites, Nature, 394:629-630.

Schumacher, B. A. and M. J. Everhart. 2004. A new assessment of plesiosaurs from the old Fort Benton Group, Central Kansas. Abstracts of oral presentations and posters, Joint Annual Meeting of the Kansas and Missouri Academies of Science, p. 50.

Schumacher, B. A. and J. E. Martin. 1995. Polycotylus sp.: A short-necked plesiosaur from the Niobrara Formation (Upper Cretaceous) of South Dakota. Jour. Vert. Paleon. 15(suppl. to 3):52A.

Sternberg, G. F. and M. V. Walker. 1957. Report on a plesiosaur skeleton from western Kansas. Kansas Academy of Science, Transactions, 60(1):86-87.

Tarsitano, S. and J. Riess. 1982. Plesiosaur locomotion - underwater flight versus rowing, N. Jb. Geol. Paläont. Abh. 164:188-192.

Tarsitano, S. and J. Riess. 1982. Considerations concerning plesiosaur locomotion, N. Jb. Geol. Paläont. Abh. 164:193-194.

Thurmond, J. T. 1968. A new polycotylid plesiosaur from the Lake Waco Formation (Cenomanian) of Texas. Jour. Paleon. 42:1289-1296.

Williston, S. W. 1902. Restoration of Dolichorhynchops osborni, a new Cretaceous plesiosaur, Kansas University Science Bulletin, 1(9):241-244, 1 plate.

Williston, S. W. 1903. North American plesiosaurs, Field Columbian Museum, Pub. 73, Geological Series, 2(1):1-79, 29 plates.

Williston, S. W. 1906. North American plesiosaurs: Elasmosaurus, Cimoliasaurus, and Polycotylus, Amer. Jour. Sci. ser. 4, 21(123):221-234, 4 pl.

Williston, S. W. 1907. The skull of Brachauchenius, with special observations on the relationships of the plesiosaurs. United States National Museum Proceedings 32:477-489. pls. 34-37.

Williston, S. W. 1908. North American plesiosaurs: Trinacromerum. Journal of Geology 16:715-735. figs. 1-15.

Williston, S. W. 1914. Water reptiles of the past and present. Chicago Univ. Press. 251 pp