>>consultations with descendant Indigenous collaborators to learn the identity of these humanoid figures. Unfortunately, they remain a mystery.

If you've spent time in the Southwest, descendant groups being tight-lipped is not surprising. There are petroglyphs in many places. Some are quite cryptic - and the "descendant groups" are not saying much other than that, yes, they know what they are. I'd speculate that making the knowledge common would diminish the 'power' of the images, but WTH do I know?