Alternate Dinosaurs: Tyrannosaurs

History
The tryannosaurs evolved in the Mid-Jurrasic from the earliest tryannosaur, †Proceratosaurus bradleyi. However, they remainded rather rare until the late Cretaceous, where they mushroomed into big beasts like †T-rex. However, the great dense forests of the Eocene nearly caused them to go extinct; but they managed to escaped extinction one way, by downsizing. During the Oligcene and Miocene however, the small tryannosaurs went on decline as area of woodland and rainforest were replaced by open grassland. Some of the tryannosaurs became big again as a result. When India collided with mainland Asia, the tryannosaurs were quick to populate the area. The same happened when Europe was no longer a bunch of islands, and when South America connected to North America.

North American Tryannosaurs

 * Plains Hastener
 * North American Ridgehead
 * Woodland Swifty
 * Wetlands Swifty

South America Tryannosaurs

 * Savannah Hastener
 * Rainforest Swifty

Asian Tryannosaurs

 * Siberian Ridgehead
 * Conifer Swifty
 * Indian Swifty
 * Indian Hastener
 * Desert Hastener
 * Desert Swifty

European Tryannosaurs

 * European Hastener
 * Eurpoean Swifty
 * European Ridgehead