Until recently, the distribution of Dactylomys dactylinus was considered to be restricted to forest habitats from the western Amazon to the east of the Xingu River in Brazil. Individuals of D. dactylinus were rescued in January 1997 from the rising waters of the hydroelectric dam of Serra da Mesa, in Central Brazil. This record extends the southern limit of the distribution of D. dactylinus, and represents also the first occurrence of this species in the Cerrado biome. The specimens were collected in patches of gallery forest of the Tocantins River and its tributaries. The Tocantins is the main river of the Araguaia-Tocantins basin. Its headwaters are located in the Cerrado biome and it is a tributary of the delta of the Amazonas River. The presence of D. dactylinus, a characteristic Amazonian lowland forest species, in the core area of the Cerrado is an evidence of the role of forested environments as mesic corridors that have been contributing to the increase of mammalian diversity in this biome.
biogeography; distribution; gallery forests
