Agree, except on Tyrannosaurus point - most Plesiosauri had iirc quite small teeth, optimised for fish-catching, not biting clean through something large and/or armored. While Tyrannosaurus/Tarbosaurus had teeth very good for just such task. Of course, it was smaller - it's land carnivore, after all.
And I can repeat that if we go to mammals than Mobi Dick makes very fine Oceania summon/hero (!) indeed.
