In the anime, they replaced Amaura with Onix.
This question is common. Anime and Games are different. I have a few things that are different: Grant's Amaura Valerie having 2 Pokemon in anime instead of 3. Olympia doing double battles in the anime Wulfric doesn't have Cryogonal in the Anime. No lysandre's zygarde thingy in the Game. Winona doesn't have skarmory. Norman has Slakoth,vigoroth, and slaking in the anime, instead of a vigoroth and 2 slakings
Source: Experience