Xiphactinus audax – Two huge lower jaws (dentary) are positioned “side by side” in an almost life-like articulation. Jaws measure 12.5” long and 4” across at widest point. Longest tooth measures 1 7/8” long. The massive bone, along with the three (3) large teeth, is in excellent condition. Other teeth are exposed in both jaws. Wonderful specimen of this classic genus! Showy!
Xiphactinus, an ichthyodectid teleost, was the largest known bony fish, reaching a known size of sixteen feet. It lived primarily in a vast inland sea that covered much of interior North America during the late Cretaceous (95-65 million years ago). Xiphactinus occupied this Cretaceous seaway for five million years and was one of the alpha predators that migrated from the Arctic Circle to the Gulf of Texas. The largest and most complete specimens are found in the Niobrara Formation, primarily in the western part of Kansas.
Ichthyodectids appeared in the Jurassic and reached a peak of diversity, size, and abundance during the Cretaceous, then suffered a decline, with a few surviving into the Eocene.