So, 2 questions here, As shown in Age of Extinction, 

1. Why were the Dinobots SO much larger than the Autobots? They were nearly 5 times that of Optimus Prime, and Prime himself is almost 1.5 times the rest of the Autobots. Why were they so gigantic? Is it something referring back to the comic/anime versions?

2. Why do they have ALT-modes as dinosaurs? All Transformers scan surrounding vehicles to gain their ALT-mode. Where did the dinobots acquire theirs'?