Simplify the following text for a Grade 12 native English-speaking person.
Original: The earliest Gavialoidea may or may not have been related to the modern types : some died out at the same time as the dinosaurs ( at the end of the Cretaceous ) , others survived until the early Eocene ( about 35 million years ago ) .
Simplified: The earliest gharial may have been related to the modern types : some died out at the same time as the dinosaurs ( at the end of the Cretaceous ) , others survived until the early Eocene .