Bus-Sized Mosasaur Hunted North Dakota Rivers 66 Million Years Ago

Scientists say 40ft prehistoric sea monster may also have terrorised rivers

The mosasaur may have occupied a similar niche to modern-day saltwater crocodiles

Palaeontology: Ancient tooth suggests ocean predator could hunt in rivers

A 66-million-year-old tooth discovered in North Dakota, USA, suggests that some mosasaurs — extinct lizard-like reptiles that could grow up to 12 metres long — may have hunted in rivers as well as seas. The authors suggest that the findings, which are published in BMC Zoology...

"It Was Bigger Than A Killer Whale": 66 Million-Year-Old Tooth Suggests Mosasaurs Were Hunting In Rivers, Not Just Seas

As if having to evade T. rexes wasn’t scary enough without these monsters lurking every time you came to drink.

Scientists discover ancient river-dwelling mosasaur in North Dakota

The chemical composition of the tooth provided evidence that the animal was adapted to riverine rather than purely marine environments.

Mosasaurs may have terrorized rivers as well as oceans

Nearly 70 million years ago, mosasaurs were the stuff of nightmares. Multiple species of the apex marine reptiles lived during the Late Cretaceous, often growing anywhere from 30 to 40 feet-long. But as dangerous as the ancient, great white shark-sized were for their prehistoric ocean prey, paleontologists have long assumed mosasaurs stuck to saltwater. A tooth recently found in the famous Hell Creek formation in Montana suggests otherwise. Acco…

880 - Mosasaur

Looking at the wide open spaces of North Dakota, it’s hard to believe that it was once covered by unfathomable depths of marine waters. Most recently, from about 80 million to 60 million years ago, the rolling hills and farmland of the Rendezvous Region was covered by seas that extended across the northern Plains, the dark, murky water home to prehistoric sea monsters.