Here we summarize the geographical distribution and host occurrence of Dipetalonema spp. in Central and South American primates, and report the first record of Dipetalonema gracile in Ecuador from a squirrel monkey Saimiri sciureus. We also provide additional data on the morphology of D. gracile including scanning electron microscope (SEM) photographs. The 6 species of Dipetalonema are known from 19 species, representing 9 genera of Platyrrhini monkeys. Dipetalonema spp. are widespread both geographically and in time, starting in 1809 and ranging from southern Mexico to central Bolivia and subtropical Brazil. Dipetalonema freitasi, Dipetalonema yatesi, Dipetalonema robini, and Dipetalonema graciliformis are known from only a few records from 1 or 2 localities, whereas Dipetalonema caudispina and D. gracile are known from multiple localities. Dipetalonema caudispina seems to be an Amazonian species, in contrast to D. gracile, which is widespread from 20°N (México) to 24°S (Paraguay and Brazil). Specimens of D. gracile in this report are similar to those presented by other authors from different host species and countries. SEM revealed a smooth cuticle on the head, and complex striations on the tail. Morphological comparisons with the other 5 species of Dipetalonema are also presented.