Dinosaurs are reptiles that existed on Earth from 230 million years to 65 million years ago.
The dinosaurs were killed by the Brain Spawn, and this information was revealed in the year 3004 to Fry that it was the brains who wiped them out. When Fry, Professor Farnsworth, and Bender were using the Forwards Time Machine in "The Late Philip J. Fry" Fry missed the dinosaurs while the latter two were able to see them before going extinct.