My best guesses are Teratornis or Aiolornis, of course scaled/spiced up with some extra Ark flare, I'm so excited for the desert biome! Now if only we could get some extra flare for us Merfolk!
Dang it you beat me to it lol. I'm going to say judging from dossier scraps that you can store water in the sail/hump maybe go so far as to say it generates water from eating - hmu wild card lol
Giant Armadillo Girdled Lizard! What call name it after its genus, Ouroboros! Let it be a faster, battle mount version of the Doedic! Locomotion included, seeing as that's how it moves in real life.