I think with the mysterious mysteries dossiers we can hope they're already going to be in the game when the desert biome launches, back when they relaunched sotf and the trailer showed a tiny snippet of in game desert, we also saw them working on the armoured lizard, so, and this is just one assumption, they're teasing the creatures they've created for the desert already, so when the map comes out, we'll have all these new creatures along with it and they're actual corresponding dossiers, presumably followed by them adding more desert creatures following the launch