IMPRESSIVE MARINE PREDATOR Xiphactinus audax Upper... Lot 3

IMPRESSIVE MARINE PREDATOR Xiphactinus audax Upper Cretaceous (86-72 MA) Niobrara formation, Kansas, USA H. 59 in - L. 165 ½ in Commonly called "the X-Fish", Xiphactinus audax is a huge predatory bony fish that roamed the warm, shallow waters of the Western Interior Seaway in what is now the central part of North America during the Late Cretaceous. It is undoubtedly the largest teleost fish known in the Late Cretaceous of North America, characterized by a heavy skull with frighteningly long teeth and a long, robust body. The vertebrae of an averagesized individual were about 5 centimeters in diameter and 3 centimeters long. Xiphactinus audax was a voracious predatory fish, a skilled competitor to the large predatory marine reptiles of the time. Its largest teeth, located in the upper jaw, were about 8 cm long and had a conical shape suitable for grasping prey. When the single tooth was ready to be replaced, two smaller teeth grew one on each side to take its place. Its name in Latin and Greek means "sword-ray" and refers to its long, narrow, sword-like body, while the thin bones, which supported the fin membrane, remind of rays and could reach 55 centimeters in length. In 1922 in The Fossils of the South Down, Dr. Gideon Mantell first referred to a find probably belonging to this genus, describing it as the lower jaw of a fish, but without giving it a specific name. Louis Agassiz in his work Recherches sur les Poissons Fossiles (1833-1845), took up Mantell's illustration and published another drawing of what he correctly considered a fish jaw, along with depictions of other remains from the same locality. In 1870 Dr. Joseph Leidy, starting with a 40.6-cm-long pectoral spine fragment (USNM V52), collected in Kansas and donated to the Smithsonian by Dr. George M. Sternberg, attributed the name Xiphactinus audax, and in the 1873 Contributions to the Extinct Vertebrate Fauna of the Western Territories, he gave a more complete description of the new genus. The imposing and fearsome appearance of Xiphactinus audax has helped make it an important player not only in its ecosystem but also in several documentaries. In fact, it appears in BBC's Sea Monters, in National Geographic's Sea Monters: A Prehistoric Adventure, and in the Titanic Creatures series.