The basic divisions of the family Micropterigidae are discussed. Hypomartyria micropteroides n.gen., n.sp. from Osorno province, Chile, and Squamicornia aequatoriella n.gen., n.sp. from Napo province, Ecuador, are described; they are the first genuine micropterigids recorded from South America. The new taxa are assigned to the Sabatinca-group of genera, and their cladistic relations within the group are tentatively assessed. Hypomartyria appears to be derived from an ancestor closely similar to that of the entire group. Squamicornia exhibits some possible synapomorphies with Old World southern hemisphere taxa. There is no evidence that the two South American genera are each other's closest relatives.