Geographic distribution of small non-volant mammals in the Araguaia and Paraná basins, south-central region of Brazil

Abstract

We collected small mammals in two hydrographic basins in central Brazil, namely the Paraná and Araguaia basins, with the aim of examining the composition of forest dwelling small mammal species and to compare their geographic distributions. Fourteen sites were sampled, eight in the Paraná basin and six in the Araguaia basin. A total of 20 species of small mammals was registered (8 marsupials and 12 rodents), 16 of them in live traps (5,253 trap-nights) and eight in pitfalls (224 trap-nights), adding to a total of 161 captures of 139 individuals. The Paraná basin showed 16 species (trap-nights: 3,115 and 104 respectively) and the Araguaia basin 11 species (trap-nights: 2,138 and 120 respectively), being both richness similar when the rarefaction method was applied. Seven (35%) out of the 20 species recorded occurred in both basins. The marsupial Didelphis albiventris Lund, 1840 was the most abundant species. The marsupials species recorded were D. albiventris, Caluromys philander (Linnaeus, 1758), Cryptonanus cf. agricolai Voss, Lunde & Jansa, 2005, Gracilinanus agilis (Burmeister, 1854), G. microtarsus (Wagner, 1842), Lutreolina crassicaudata (Desmarest, 1804), Marmosa murina (Linnaeus, 1758), and Philander opossum (Linnaeus, 1758). The rodent species recorded were Akodon gr. cursor, Calomys tener (Winge, 1887), Nectomys rattus (Pelzen, 1883), N. squamipes (Brants, 1827), Oecomys bicolor (Tomes, 1860), Oryzomys maracajuensis Langguth & Bonvicino, 2002, Oryzomys cf. marinhus, O. megacephalus (Fischer, 1814), Oligoryzomys fornesi (Massoia, 1973), Oligoryzomys sp., Proechimys longicaudatus (Rengger, 1830) and P. roberti (Thomas, 1901). The range extension of some species is discussed, in addition to biogeographic considerations. The Caiapós Mountains may have been a geographic barrier for some small mammal species in the face of the retraction and expansion of forests in the past.