Usually mosasaurs and plesiosaurs and pliosaurs and all sorts of other marine reptillians which have taken on whale-like roles in the past... all the reconstructions nowadays never show them with much fleshiness on the face... or even much insulation, even though most water animals get a bit extra choob even in tropical waters.

So here's a Tylosaurus, which is a mosasaur, with a sounding structure on the face (where there's these huge honkin' nasal cavities in the skull specimens--most critters with those have something special up with their nose like whales and elephants and such.) and plenty choob.