Monkey with a bat-like nose

This is the face of a Black Snub-nosed Monkey.  The nose looks to me like it should belong to a bat rather than a simian.  This morning I tried to look up why a monkey would evolve such an unusual nasal shape, and found some reports that bat noses are used in their echolocation process.  I knew about the ears, but hadn't thought about the source of the sonar, which apparently - at least in some species - is emitted by the nose.

So, back to this monkey's nose.  Does he/she use it to produce sounds?  There must be some major evolutionary advantage, because losing the external prominence means losing the thermal warming a nose would provide, and much of the particulate filtering, which might be disadvantages.  I haven't found anything, but don't have time to search far.  Perhaps someone out there knows...

Via Zumbi.