Xiphactinus audax Variante:Sin imprimar thick neck and a robust

thick neck and a robust body

with rapid growth during their teenage years

suggesting relatively high longevities for large theropods

a Smilodon populator

Xiphactinus audax Variante:Sin imprimar thick neck and a robustXiphactinus audax was a large predatory bony fish from the Late Cretaceous of North America, known primarily from fossils recovered from marine deposits of the former Western Interior Seaway, especially the Niobrara Formation of Kansas, although its distribution extended across much of the North American interior basin. Originally described by Joseph Leidy in 1870, this taxon belongs to Ichthyodectiformes, a group of Mesozoic actinopterygian fishes