The Mississippi River occupies an ancient geologic structure called the Mississippi Embayment, which was inundated by the Western Interior Sea Way during the Cretaceous period. Mosasaur fossils ...

This salt tolerance likely gave Deinosuchus a powerful edge during the Late Cretaceous, allowing it to move freely through the Western Interior Seaway—a vast inland sea that split North America ...

Salt tolerance would have helped Deinosuchus navigate the Western Interior Seaway that once divided North America, during a greenhouse phase marked by global sea level rise.

The seaway appeared about 100 million years ago, making it approximately 20 million years older than the earliest known Deinosuchus fossils. “The picture wasn’t very coherent,” Rabi said.

An artist's illustration shows Deinosuchus riograndensis swimming with an early alligator relative in the wetlands of the Western Interior Seaway in southwestern North America, during the Late ...

An artist's illustration shows Deinosuchus riograndensis swimming with an early alligator relative in the wetlands of the Western Interior Seaway in southwestern North America, during the Late ...

The team also highlighted significant regional variations. The gradual disappearance of the Western Interior Seaway profoundly altered North American landscapes. These geographical upheavals created ...

And although Deinosuchus lived in freshwater, it could also be found in brackish waters. At the time, the continent was cut into two by the Western Interior Seaway, also known as the Cretaceous Seaway ...

BOULDER, Colo. — Paleontologists recently discovered a rare mammal fossil in western Colorado. It's a genus of mammal that lived between 70 million and 75 million years ago and has never been ...

Paleontologists have discovered a new prehistoric mammal species in Colorado that lived during the age of the dinosaurs and may have been a swamp-dweller. In a study published in the journal PLOS ...