The Late Cretaceous apex predator easily grew to the size of a great white shark. Mosasaurs mostly stuck to ocean habitats, but evidence now suggests they sometime ventured elsewhere...
A tooth recently found in the famous Hell Creek formation in Montana suggests otherwise.
According to findings published on December 11 in the journal BMC Zoology, at least one mosasaur species may have pursued their meals upstream into freshwater rivers...
Hell Creek includes some of the world’s most diverse troves of Upper Cretaceous and lower Paleocene fossils. In addition to land dinosaurs like Tyrannosaurs and Triceratops, the region was also home to aquatic species like mosasaurs.
While nowhere near an ocean today, the area included rivers connecting into a long-gone body of water called the Western Interior Seaway around 66 million years ago....
