When the animals of Earth's Mesozoic Era start to appear on the planet, they set in motion, a series of events are triggered that began the changing of the order of the natural world.

These are the stories of the ponies dealing with, and interacting with dinosaurs, reptiles, and mammals of the Triassic, Jurassic, and Cretaceous Periods...

The top conditions for your story to be considered a part of The Age of Dinosaurs-verse are the following;

1. - The animals you include HAVE to be from the Mesozoic Era;
Triassic Period (250-to-200 million years ago, roughly)
Jurassic Period (200-to-145 million years ago)
Cretaceous Period (145-to-66 million years ago)

2. - The animals you use HAVE to be accurate to the most recent science of any given animal you put in...Example: Tyrannosaurus and Triceratops is covered in feathers, or Velociraptor is a turkey-sized, pack hunting, bird-like animal...

3. - The dinosaurs can be portrayed as being able to speak in their "native-language", but be a little more creative with their names for themselves or other dinosaurs. A forum explaining this will be made in the future...