The biodiversity of Lepidoptera is largely understudied in tropical ecosystems and sub-Saharan Africa in particular. This phenomenon, known as the Taxonomic Impediment , implies the incomplete information on taxonomy and distribution. This is especially true for lepidopteran species that are small in size, cryptically coloured, and morphologically similar, often with closely resembling forewing pattern occurring in numerous species. Our recent field work (12-27 May, 2012) in the Yangambi Biosphere Reserve, province Orientale, Democratic Republic of the Congo, yielded an enormous richness of new species of the Old World. Many of them belong to small, obscure genera which are up to now considered as monotypic. We promote inter-institutional but targeted team studies which are conducted with the necessary methodological precision and an integrative approach. The enormously rich, dynamic, constantly evolving and complex African lepidopteran fauna is not only a challenge for taxonomists of the 21st century but in many cases offers the key to solve the phylogenetic relationships of higher taxa and also assists to answer the question of how the Lepidoptera colonized the world.