Very interesting species! And both the male and female have the facial characteristic? That would rule out the red feature being part of attracting a mate.
I'm with @vm2904 that it must be some kind of protection element to ward off predators. Not sure how that would work, but evolution does everything for a reason .
Thanks for sharing!!
While I do not believe in macro-evolution, I certainly agree with the reason and purpose for things, even if we do not understand it.