New species of Rhainopomma and of Altiusambilla from the northern part of the Eastern Arc mountains of Tanzania are described, based on morphological, molecular and geographical data. Ancestors of the genera Usambilla, Rhainopomma and Altiusambilla probably spread when a different climatic regime favored forest cover connecting presently isolated high mountains of East Africa. After forests retreated, allopatric speciation was the driving force resulting in the biographical pattern of closely related lentulid species we see today in the Eastern Arc mountains and inland volcanoes of Tanzania and Kenya.