Dados do Trabalho

TÍTULO

SIGMODONTINAE FOSSILS FROM SERRA DA BODOQUENA, MATO GROSSO DO SUL, BRAZIL

Resumo

Sigmodontinae rodents are extremely diversified in the Neotropics but their fossil record remains generally poorly known. In Brazil, thirty-one taxa are recognized as fossils, although this number increased since the last revision due to recent inventories published in the last decade. The knowledge about the Cenozoic fossil fauna of the Brazilian state of Mato Grosso do Sul is still incipient, possibly more due to lack of studies than to the absence of fossil sites. Here, we re-evaluate the fossil assemblage of sigmodontines from Serra da Bodoquena (Mato Grosso do Sul), describing new records for the Quaternary fauna of the region and for Brazil. The material was collected in Nossa Senhora Aparecida (NSA, 21° 5'27.89"S 56°34'28.77"W) cave, in the Municipality of Bonito. Firstly, samples were taken from the superficial organic layer and then sediments were removed every 20cm. Seven stratigraphic units were recognized and samples of these sediments were screen-washed. The material recovered was cleaned with needle and brush and analysed under a stereomicroscope. Taxonomic identification was based on dental and cranial structures using current literature and direct comparisons with recent specimens. All examined material is deposited in the paleontological mammal-collection of the Department of Vertebrates (Mammalogy), Museu Nacional – UFRJ, Rio de Janeiro. Twenty-four species were identified from 601 cranium remains. The most abundant species along all stratigraphic units are Necromys lasiurus and Pseudoryzomys simplex. Among less common taxa are Oecomys sp., Rhipidomys cf. macrurus and Euryoryzomys sp., each occurrence based on a single specimen. We described the presence of some new species not previously recorded for the region, as Bibimys cf. labiosus, Graomys cf. chacoensis, Thalpomys lasiotis, Scapteromys sp. and Wiedomys sp. This fossil assemblage seems to be similar to others fossil sites in Brazil, such as those from Goiás and Rio Grande do Sul, with predominance of species from open areas, including grasslands, wetlands and some of forested environments from Cerrado landscapes. The high diversity and occurrence of species different environments may be related to the strategic position of the Serra da Bodoquena as a confluence of ecoregions as the Atlantic rainforest, Cerrado, Pantanal and Chaco. However, it may be precipitated to discuss paleontological scenarios of the Quaternary for the Bodoquena region, since no age of the deposits are yet available.

Palavras-chave

Rodents, Quaternary, Cenozoic, Cerrado, Pantanal

Financiamento

This work was supported by Coordenaçao de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) - Finance Code 001.