Certain primates and other mammals have demonstrated the ability to push the boundaries of the detection of wavelengths of light beyond the V and into the UV range. This article:
http://rspb.royalsocietypublishing.org/content/279/1727/387.full.pdf+html?sid=ae2c449a-5f45-40f3-9bbc-bb94572d7f35 (see links on right side of page for PDF access)
explores the specific mechanism for spectral tuning in primates using the aye-aye as a case study and determines that primates undergo spectral tuning at a site distinct from the one correlated with spectral tuning in most other mammals. This finding does not preclude the possibility of similar deep evolutionary origins of similar spectral tuning mechanisms across primates and mammals but has interesting implications for the comparatively recent evolutionary history of primate spectral tuning.