Dimidiogalumna (Oribatida, Galumnidae) currently comprises seven species collectively distributed in the Paleotropical and southern Palaearctic regions. We describe a new species—D. dhatywalalensis sp. nov.—based on adults collected from litter in a bamboo forest in Western Ethiopia. The new species differs from all known species of the genus by the presence of a specific tuberculate sculpturing in the anterolateral part of the pteromorph. An identification key and summary of distribution and habitats of the known species of Dimidiogalumna are provided.