High in the forested canopy of Democratic Republic of Congo, an all-black monkey turned its back to a photographer’s camera. Over the next several years, Amboko and his colleagues returned to the dense, closed-canopy forest, where the mystery monkey shared its range with seven other monkey species and bonobos. “And my first impression of the skull was that it was very similar to Colobus satanas but so much smaller.” The monkey was, in fact, a new species, to science earning the name Colobus congoensis, Amboko and colleagues report July 15 in PLOS ONE. The new monkey species might already be at risk of being threatened or endangered.