Lemur of mouse lemurs, the gray mouse lemur ("M. murinus"), golden-brown mouse lemur ("M. ravelobensis"), and Goodman's mouse lemur ("M. lehilahytsara") were considered the same species until recently, when genetic tests identified them as cryptic species. The lemur dentition is heterodont (having multiple tooth morphologies) and derives from an ancestral primate permanent dentition of . Indriids, sportive lemurs, the aye-aye, and the extinct sloth lemurs, monkey lemurs, and koala lemurs have reduced dentitions, having lost incisors, canines, or premolars. The ancestral deciduous dentition is , but young indriids, aye-ayes, koala lemurs, sloth lemurs, and probably monkey lemurs have fewer deciduous teeth.
Dentition later that tooth emergence begins, the earlier the anterior teeth (I1–P4) appear in the sequence. Dentition, or the study of teeth, is an important area of study for archaeologists, especially those specializing in the study of older remains. Dentition affords many advantages over studying the rest of the skeleton itself (osteometry). The structure and arrangement of teeth is constant and, although it is inherited, does not undergo extensive change during environmental change, dietary specializations, or alterations in use patterns. The rest of the skeleton is much more likely to exhibit change because of adaptation. Teeth also preserve better than bone,