This incredible critter is Callicebus caquetensis, a species of titi monkey newly discovered in the Colombian Amazon. Humans have destroyed their natural habitat, leaving less than 250 in the wild. No wonder he looks freaked out in the photo. From New Scientist:
The monkey was found in a region called Caquetá, in the south of Colombia, which had been inaccessible for many years due to a violent insurgence.
About the size of a cat, the Caquetá titi has grey-brown hair and makes an extremely complex call. Unusually for a primate, it forms lifelong monogamous pairs.
"New monkey species already looks scared"