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:
Press N to open the Properties 3D view sidepanel, and disable the Textured Solid item under the Shading subpanel.
Click on the 11th scene layer button to reveal the Gidiosaurus_lowres object and select it; go into the Side view, zoom in to the head, and enter Edit Mode. Press the A key to select all the vertices of the mesh.
Put the mouse pointer inside the UV/Image Editor, select all the UV vertices (again the A key), and pin them by pressing the P key; then...