The skull of Brachauchenius lucasi Williston 1903 A photographic atlas of  FHSM VP-321   Copyright © 2002-2008 by Mike Everhart Page created 11/30/2002; revised 01/06/2008

The only pliosaur recognized from Kansas at this time is Brachauchenius lucasi Williston 1903. A few fragmentary specimens suggest other species may be present. In Kansas, these short-necked pliosaurs are relatively rare, but are represented by two excellent specimens, the largest of which is on exhibit at the Sternberg Museum of Natural History.  This specimen was found on June 5, 1951 by Robert and Frank Jennrich in Russell County while hunting sharks teeth. It was collected by G. F. Sternberg, with the help of the Jennrich brothers.  The lower jaw is 68 inches (170 cm) long.

See these other webpages: Pliosaurs and Polycotylids  and  Kronosaurus for more information.

Somewhere in the Western Interior Sea, a giant pliosaur (Brachauchenius lucasi) is about to make lunch out of a small turtle similar to Desmatochelys.  Brachauchenius was one of the last of the pliosaurs and made it's final appearance in Kansas during the deposition of the Fairport Chalk Member (lower Turonian) of the Carlile Shale. Varner painting courtesy of the Museum of Northern Arizona.

Brachauchenius lucasi Williston is certainly the largest of the pliosaurs known from Kansas. The holotype (USNM 4989- LEFT) was collected from the "Benton Formation" in Ottawa County, Kansas, and was described by Samuel Williston in 1903. The skull is mounted upside-down, with 37 vertebrae. Skull length is 90 cm (Williston, 1907).         Click here for Williston's drawing of the reconstruction skull of the holotype specimen.  SYSTEMATIC PALEONTOLOGY Order Plesiosauria, de Blainville 1835 Superfamily Plesiosauroidea, Welles 1943 Family Brachaucheniidae Williston 1925 Genus Brachauchenius lucasi Williston 1903

A second specimen (USNM 2361, LEFT) was collected from the Eagle Ford Formation, on Bouldin Creek near Austin, Texas, and described by Williston in 1907. Skull length is 80 cm (Williston, 1907).

LEFT: The partial skull of a Brachauchenius lucasi (UNSM 50136) specimen from an unknown locality in Kansas. Very similar in size and preservation to FHSM VP-321 (above). RIGHT: A portion of the skull and a jaw with teeth of a Brachauchenius lucasi specimen (UNSM 112437) from Mitchell County discovered in the Graneros Shale during the construction of the Glen Elder Dam. Possibly the oldest known specimen of this species. (Both specimens in the collection of the University of Nebraska State Museum)

The skull of a third specimen (FHSM VP 321, shown below) is much larger, more complete, and somewhat better preserved than either of the two earlier specimens. It was collected by George Sternberg in October, 1951, from the Fairport Chalk Member of the Carlile Shale (Middle Turonian) near the town of Fairport in northwest Russell County, Kansas.

The skull of VP-321 is on exhibit in the Sternberg Museum of Natural History at Fort Hays State University.  A cast of the skull is also on display at the University of Kansas Museum of Natural History, Lawrence, Kansas. This skull is about five feet (152 cm) in length along the mid-line, and must have come from a large bodied animal that is estimated to have been about 7 m (22 ft) long. Williston (1907) and Carpenter (1996) agree that Brachauchenius is closely related to the Jurassic pliosaur, Liopleurodon ferox.  Additional Brachauchenius remains were discovered in Russell County (Pers. comm, J. D. Stewart, 1999) but have not yet been described. Click on the pictures below to see details of skull of FHSM VP-321:

The figure at LEFT is from a 1994 draft of Carpenter (1996) and is copyright © by Kenneth Carpenter; used with permission of Kenneth Carpenter. CLICK TO ENLARGE. Key to bones of the skull and lower jaw of Brachauchenius lucasi Williston: d - dentary; ep - epipterygoid; fr - frontal; ju - jugal; mx maxilla; o - orbit; p - pineal foramen; pa - parietal; pal - palatine; pf - prefrontal; pm - premaxilla; pt - pterygoid; en - external nares; q - quadrate; qpt - quadrate ramus of pterygoid; sa - surangular; sq -squamosal; tf - temporal fenestra

References:

Carpenter, K. 1996. A Review of short-necked plesiosaurs from the Cretaceous of the western interior, North America, N.Jb. Geol. Palaont. Abh., (Stuttgart), 201(2):259-287.

Schumacher, B. A. and M. J. Everhart. 2005. A stratigraphic and taxonomic review of plesiosaurs from the old “Fort Benton Group” of central Kansas: A new assessment of old records. Paludicola 5(2): 33-54.

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

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.