Many U.S. states designate official state fossils to recognize their unique paleontological heritage. These fossils highlight a state’s prehistoric past, educating the public about ancient life forms and promoting interest in natural history.
Kansas’ Official State Fossil
Kansas officially designated Tylosaurus as its state marine fossil in 2014. That same year, Pteranodon became the state’s official flying fossil. Although Xiphactinus audax is a significant Kansas fossil, it was not chosen as the official state marine fossil. Nevertheless, Xiphactinus audax remains strongly associated with Kansas due to the abundance and quality of its fossil discoveries.
Understanding Xiphactinus audax
Xiphactinus audax was a large predatory bony fish that inhabited the ancient Western Interior Seaway during the Late Cretaceous Period, approximately 87 to 82 million years ago. It could reach lengths of 16 to 20 feet (5 to 6 meters), making it one of the largest bony fish of its era. Its appearance has been likened to a massive, fanged tarpon, reflecting its streamlined body built for speed.
The fish possessed a sleek, torpedo-shaped body, with powerful pectoral fins and a forked caudal fin for rapid movement. Its most striking feature was a massive head equipped with large jaws lined with sharp, conical teeth that could measure several inches long. Xiphactinus audax was a voracious carnivore, preying on other fish, smaller marine reptiles, and even pterosaurs. Evidence of its feeding habits comes from “fish-within-a-fish” fossils, where specimens are found with large, undigested prey inside their stomachs.
Its Legacy in Kansas
Kansas holds a prominent place in the paleontological record of Xiphactinus audax due to numerous discoveries within its Niobrara Chalk Formation. The first specimen was identified in Kansas in 1870, marking the beginning of the state’s long association with the fish. The Niobrara Chalk beds are known for yielding well-preserved Xiphactinus fossils, including dozens of complete skeletons and countless vertebrae.
Among the most famous finds is the “fish-within-a-fish” fossil, unearthed in Smokey Hill, Kansas, showing a Xiphactinus with a nearly intact 6-foot-long Gillicus arcuatus inside it. This specimen, now housed at the Sternberg Museum of Natural History in Hays, Kansas, provides insight into the predator-prey dynamics of the ancient seaway. Other Kansas discoveries have revealed Xiphactinus specimens with shark teeth embedded in their bones, illustrating complex interactions within the Cretaceous marine ecosystem. The abundance and quality of Xiphactinus fossils from Kansas have advanced understanding of this ancient predator and the prehistoric marine environment.