Karyotype description of two species of the genus Akodon (Rodentia, Sigmodontinae) in the northern Rio Grande do Sul state, Brazil

Abstract

Among the sigmodontine rodents, the genus Akodon is the second in numerical terms, with about 45 recognized species. In the Rio Grande do Sul state, there are 5 registered species. This article shows data on the distribution of the species of the genus Akodon in the northern Rio Grande do Sul state, as well as a description of the karyotypes of species from this region are shown. Six localities were sampled from August 2008 to May 2010. A total of 44 specimens underwent cytogenetic analysis and 2 species were identified (Akodon montensis and Akodon paranaensis). The karyotype of A. montensis was 2n = 24, FN = 44 and that of A. paranaensis was 2n = 44, NF = 46. Data on abundance and distribution of these species corroborate the pattern described in other studies with the rodent community in the northern portion of the state, where the Akodon species are seen as dominant. The fact that only A. montensis and A. paranaensis were captured is an indication that these two species are the only ones with confirmed occurrence in the northern portion of this state.