This 19 October 2018 video says about itself:
Mosasaurs 101 | National Geographic
Mosasaurs were Earth’s last great marine reptiles. Learn about the surprising places they’d hunt, how some species dwarfed even the Tyrannosaurus rex, and how key physical adaptations allowed these reptiles to become prehistoric apex predators.
Another video used to say about itself:
15 September 2018
Mosasaurs are one of the largest families of non-dinosaur reptiles to exist during the age of dinosaurs. Mosasaurs are aquatic reptiles that are closely related to modern day snakes and monitor lizards.
There are numerous Mosasaurids or Mosasaur family species that can be compared.
The Mosasaurus is famous for being in the Jurassic Park film franchise.
Mosasaurids were the apex predators of the ancient seas often in competition with sharks and pliosaurs. Predator X or Pliosaurus is still smaller than the largest Mosasaur and is similar in size and comparison to the Tylosaurus. So, have fun watching this video on Mosasaur family species comparison, of 20 species and related genera. TATA! Have fun!