Western Interior Seaway Fauna

The western interior seaway was a shallow sea filled with abundant marine life.

Western interior seaway fauna. The western interior seaway formed about 100 million years ago when the mountains that now define western north america lifted up as a result of tectonic forces. However numerous isolated paleobiogeography of cretaceous western interior seaway. The western interior seaway was a shallow sea filled with abundant marine life.

This is not true for the tetrapods. Interior seaway denizens included predatory marine reptiles such as plesiosaurs and mosasaurs that grew up to 18 meters long. And advanced bony fish including pachyrhizodus enchodus and also the massive 5 metre 16 ft long xiphactinus a.

The western interior seaway was also home to early birds including the flightless hesperornis which had stout legs for swimming through the water and small wing like appendages used for marine steering rather than flight. Aptian maastrichtian sedimentary deposits from the seaway crop out in the western interior basin of canada and the united states. It existed at its fullest extent from the mid late cretaceous period.

Many of these fossils can be viewed on this cretaceous atlas of ancient life page. Other marine life included sharks such as squalicorax cretoxyrhina and the giant shellfish eating ptychodus mortoni believed to be 10 metres 33 ft long. And the tern like ichthyornis an early avian with a toothy beak.

Other marine life included sharks such as squalicorax and the giant shellfish eating ptychodus mortoni believed to be 10 meters long. Paleogeographic reconstruction of the western interior seaway during the cretaceous. The western interior seaway was a large inland sea that started to expand in the early cretaceous period though geological evidence suggests it started to expand in the late jurassic period.

The clearwater formation provides the earliest faunal record of the western interior seaway in this area. They ve also dug up the remains of huge sharks turtles the size of cars and clams six feet in diameter the largest to ever exist. Vertebrate remains are commonly well preserved and in certain stratigraphic units abundant.