At this point, when we look at the Gidiosaurus mesh, we realize that some detail in the model is still missing; for example, the lower teeth. In fact, we modeled the mouth closed and the lower teeth, enclosed in the upper mouth rim, weren't visible.
It's now time to add them; in fact, even though we have already done the unwrapping stage, it's still possible to modify the mesh further and also update the UV islands accordingly.
Start from the last
Gidiosaurus_unwrap.blend file you saved: