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.
Eastern Highlands moist deciduous forests winds from the Bay of Bengal, which lies to the southeast. The ecoregion is bounded on the north and west by tropical dry deciduous forest ecoregions, including the Central Deccan Plateau dry deciduous forests to the southwest and west, the Narmada valley dry deciduous forests to the northwest, and the Chota Nagpur dry deciduous forests to the north and northeast. The drier Northern dry deciduous forests ecoregion, lying west of the Eastern Ghats range, is completely surrounded by the Eastern Highlands moist deciduous forests, in the rain shadow of the Ghats, which partially block the moisture-laden monsoon winds off the