From everything I've ever been told of dinosaurs it more or less depended on the situation that some of the dinosaurs were in to determine what they evolved into. I believe there was an episode of Bill Nye the Science guy where he stated that both the cow and dolphin have a common ancestor if you follow their gene sequences back far enough. Then you have alligators/crocodiles which haven't changed according to scientists for something like 1,000 years (could be wrong on this just going from memory). I believe sharks also fall into a similar category as your larger lizards.

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"BOY: On a hot summer night, would you offer your throat to the wolf with the red roses? GIRL: Will he offer me his mouth? BOY: Yes. GIRL: Will he offer me his teeth? BOY: Yes. GIRL: Will he offer me his jaws? BOY: Yes. GIRL: Will he offer me his hunger? BOY: Yes. GIRL: Again, will he offer me his hunger? BOY: Yes! GIRL: Yes. BOY: On a hot summer night, would you offer your throat to the wolf with the red roses? GIRL: Yes. BOY: I bet you say that to all the boys!" -Meatloaf