Corrected entry: When the migration is taking place, Aladar is speaking with one of the lemurs who are riding on its back. Where are the other three lemurs? The four lemurs where on its back a few shots before, but now there's only one. The next shot, however, show the other three lemurs again on its back, appearing from nowhere.
Corrected entry: When Aladar joins the herd, the triceratops exclaims that Baleen (the diplodocus) is the last of her kind. But when the Pterodctyl takes Aladar's egg and does the panoramic flight, he flies through a group of dinosaurs that have many diplodocus. (00:10:00 - 00:50:00)
Corrected entry: Across all the movie we see grass in the ground. The truth is, grass didn't exist until the Cenozoic era, and many scientific studies prove that. In the Cenozoic era, the dinosaurs had already died, so it's impossible that dinosaurs and grass existed at the same time.
Corrected entry: Across all the movie we see a variety of primates, like lemurs, etc. Actually, the primates didn't exist when the dinosaurs where in Earth. The primates appeared when the Dinosaurs had already died - many centuries after the movie it's supposed to take place.