Rodents of genus Mesomys Wagner, 1845 (Echimyidae, Eumysopinae) are generally uncommon components of the Amazonian fauna, inhabiting primary and secondary forests (Emmons & Feer, 1997).They are arboreal, nocturnal, solitary, and difficult to capture; as such, they have little representation in scientific collections and are largely unstudied (Patton & Emmons, 2015).Currently, four species are recognized for the genus: Mesomys hispidus (Desmarest, 1817), the type species (which includes