• tiny.

So it's all over the internet (here and here and here and more): Turns out that for 80 million years the ancestors of the familiar Tyrannosaurus Rex were only about the size of humans. In 2009 six new species of tyrannosaur were discovered, and the number of known species has quadrupled in the past decade!

From National Geographic:

Tyrannosaurs originated in the Middle Jurassic period, about 165 million years ago. Though they generally remained small for 80 million years, early tyrannosaur species resembled T. rex in that they were bipedal predators with "incisor like" teeth.

But significant physical differences are also in evidence. Some animals had longer arms, for instance, or relatively small heads.

"There is quite a difference between the oldest species and T. rex," Brusatte said. "But there were a hundred million years of evolution to play with."

I have nothing more to add except AWESOME!