Dinosaur Prehistoric Reptile of the Day: “Mosasaur 2" by Jonathan Kuo. NOTE THAT THIS IS NOT A DINOSAUR. Remember, I said back in the introduction that some non-dinosaur art might creep into this series, and this here’s the first one. The Mosasaurs were aquatic reptiles that lived contemporaneously with dinosaurs, but were not dinosaurs. They are, however, still freaking badass.