Didelphimorphia, Chiroptera and Rodentia from the Holocene of Gruta do Urso Fóssil, Ceará, Northeastern Brazil

Mammals’ remains are commonly and abundantly retrieved from Quaternary deposits in Brazil. However, small-sized mammals are rarely studied in detail, despite their great potential for biodiversity dynamics studies and paleoenvironmental inferences. In northeastern Brazil, there are very few Quaternary records of these organisms, especially for some states such as Ceará. This study aims at partially filling this gap, by describing Holocene remains of Didelphimorphia, Rodentia, and Chiroptera, retrieved in subsurface excavation at the Gruta do Urso Fóssil, Parque Nacional de Ubajara, State of Ceará. The specimens come from nine artificial layers of 10 cm each, some of which were dated by thermoluminescence and optically stimulated luminescence, resulting in a time interval ranging from 7000 ± 1,000 to 8450 ± 960 years BP. The unearthed mammal fauna, mostly isolated teeth and fragmented bones, are composed of (i) five species of didelphimorphian marsupials (Didelphis albiventris, D. marsupialis, Metachirus sp. Monodelphis cf. domestica, and Gracilinanus agilis); (ii) five caviomorphs rodents (Kerodon rupestris, Cuniculus sp. cf. Dasyprocta sp. Proechimys sp. and Thrichomys cf. laurentius); (iii) three sigmodontine rodents (Hylaeamys cf. megacephalus, Calomys sp. and Rhipidomys cearanus); (iv) and six chiropterans (Furipterus horrens, Carollia perspicillata, Micronycterinae indet., Chrotopterus auritus, Phyllostomus hastatus, and Artibeus sp.). Except for Proechimys, all genera still currently occur in the area. This mammal assemblage suggests wet environmental conditions at the ‘Brejo de Altitude’ in the early Holocene, similar to the current ones.