Picture* of Xiphactinus used by permission of the author Dan Varner.
This image may not be reproduced without his permission.
The most common of the ichthyodectid fish in the younger Niobrara chalks is Xiphactinus which is the largest bony fish of the Cretaceous, sometimes getting up to 20 feet (one of the largest ones was discovered in the same Cretaceous seaway in Western Kansas). Xiphactinus at least sometimes swallowed its prey whole as can be seen in the specimen on display in the Sternberg Museum of natural history. While this Iowa fish could be Xiphactinus, identification will have to wait until more of the fish is uncovered from the shale. I have been told it would be even more exciting (significant) if it were a different genus.
Evan and I have removed the shale from on top of the fossil. Evan then made a wooden frame and encased the fossil and shale matrix in plaster of paris. Click on this link to see our work in extracting the fossil. This link will take you to a description of the rocks and stratigraphy.
Hattin, D.E. and C.T. Siemers [assisted by G.F. Stewart] 1987. Guidebook Upper Cretaceous stratigraphy and depositional environments of western Kansas. for Annual meetings of American Association of Petroleum Geologists and Society of Economic Paleontologists and Mineralogists [held at Oklahoma City, Oklahoma on April 1978]. Guidebook series 3 Kansas Geological Survey. [reprint with modifications of 1978 edition] 55p.
B.J, 1981. Cretaceous vertebrate fossil of Iowa, and nearby areas of
Nebraska, South Dakota, and Minnesota. in R. L. Brenner, R. F. Bretz, B.
J. Bunker, D. L. Iles, G. A. Ludvigson, R. M. McKay, D. L. Whitley, B.
J. Witzke. Cretaceous Stratigraphy and sedimentation in Northwest
Iowa, Northeast Nebraska, and Southeast South Dakota. Iowa Geological Survey
Guidebook Series Number 4. 172 p.
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Mahaffy on May 28, 2001 (6:04PM)
Last updated on: October 26, 2009 (10:24pm)