Western Interior Seaway Animals

The western interior seaway was subtropical as far north as wyoming.

Western interior seaway animals. The western interior seaway also covered most of the shallow southeastern united states including every state adjacent to the modern day gulf of mexico. Interior seaway denizens included predatory marine reptiles such as plesiosaurs and mosasaurs that grew up to 18 metres 59 ft long. Fossils aren t the only clues the seaway left.

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 cretaceous ammonite hoploscaphites nicolletii. Although mosasaurs were solitary animals it s possible that mothers may have lived in groups to protect their young from sharks and giant predatory fish.

Mosasaurs would have lived in these waters. Other marine life included sharks such as squalicorax cretoxyrhina and the giant shellfish eating ptychodus mortoni believed to be 10 metres 33 ft long. The western interior seaway was created during one of the greatest transgression events of all time.

Truly strange animals such as the long snake necked plesiosaurs looking like sea dragons from mythology swam through the middle of our continent once. Vertebrates include dinosaurs pterosaurs crocodiles champsosaurs lizards snakes turtles frogs and salamanders. The western interior seaway contained fish and a wide variety of large marine reptiles.

It existed at its fullest extent from the mid late cretaceous period. Pterosaurs like the famous pterodactyl and swimming birds both fished the western interior seaway. The giant x fish xiphactinus which has been found in the cretaceous of the western interior seaway.

At its greatest extent it was 600 miles 970 km wide 2 000 miles 3 200 km long and had a depth maximum depth of 2 500 feet 700 m. And advanced bony fish including pachyrhizodus enchodus and also the massive 5 metre 16 ft long xiphactinus a. This specimen is on display at the university of kansas natural history museum in lawrence.