a study of the fingertip morphology of four small-bodied new world monkey species, indicated a correlation between increasing small-branch foraging and reduced flexor and extensor tubercles in distal phalanges and broadened distal parts of distal phalanges, coupled with expanded apical pads and developed epidermal ridges. this suggests that widened distal phalanges were developed in arboreal primates, rather than in quadrupedal terrestrial primates.