Remarkable species diversity in Malagasy mouse lemurs (primates, Microcebus)

Phylogenetic analysis of mtDNA sequence data confirms the observation that species diversity in the world's smallest living primate (genus Microcebus) has been greatly underestimated. The description of three species new to s cience, and the resurrection of two others from synonymy, has been justifie d on morphological grounds and is supported by evidence of reproductive iso lation in sympatry. This taxonomic revision doubles the number of recognize d mouse lemur species. The molecular data and phylogenetic analyses present ed here verify the revision and add a historical framework for understandin g mouse lemur species diversity. Phylogenetic analysis revises established hypotheses of ecogeographic constraint for the maintenance of species bound aries in these endemic Malagasy primates. Mouse lemur clades also show cons picuous patterns of regional endemism, thereby emphasizing the threat of lo cal deforestation to Madagascar's unique biodiversity.