Taxonomy and diversification of mouse lemurs: unravelling the cryptic evolution of a primate genus

The diversity of microendemic and cryptic taxa is difficult to study due to their small geographic distributions and low phenotypic distinctiveness. A striking example are the iconic lemurs of Madagascar, which underwent a controversial four-fold increase in species number since 1990, challenging the study of their diversity and evolution and the development of effective conservation strategies. Here, we integrate comprehensive genomic, morphological, ecological, and behavioral data to show that the taxonomy of one of the most speciose primate genera, the cryptic mouse lemurs (genus Microcebus), has been inflated. We propose to synonymize six of the currently 25 described Microcebus species, as their differentiation to the closest sister taxon can be explained through intraspecific clinal variation. We highlight changes in conservation status resulting from this taxonomic update. In addition, we provide the first comprehensive phylogeny for the genus and show that its diversification occurred during the late Pleistocene, possibly facilitated through climatic fluctuations and species-pump effects of humid rainforests. Our work does not only shed light on the taxonomy and diversification of mouse lemurs but provides a practical framework for integrative taxonomy that can facilitate the study of primate diversity and conservation worldwide.