The Cretaceous-Tertiary Mass Extinction Event is an event that kills nearly all the reptiles on earth, including reptilian dinosaurs. This happened 65,000,000 years ago. Only one group of dinosaurs survives, not 

Dinosaur death

The asteroid that wiped out 75 percent of life, including all of the non avian dinosaurs.

reptiles but birds. An asteroid is believed to wipe out the 75 percent of life that died out. In Prehistoric Park, Nigel saves Terrence and Matilda just before the shock waves from the asteroid reaches Montana

T. rex death

Tyrannosaurus rex was around for the last 2 million years of the rule of the non avian dinosaurs!