Radiocarbon dating and integrative paleoecology (ẟ13C, stereomicrowear) of Eremotherium laurillardi (LUND, 1842) from midwest region of the Brazilian intertropical region

Abstract

The knowledge on the Pleistocene biota that inhabited the Brazilian midwestern region is scarce and no data on the paleoecology of Eremotherium laurillardi from this region have been published so far. The main objective of this study is to provide information about the age and feeding ecology of that taxon from Goiás state and to compare the results with other localities from the Brazilian Intertropical Region (BIR). Carbon isotope and stereomicrowear analyses were performed in a molariform from the left maxilla found in Piranhas municipality. The results include a14C AMS dating of 32,390 ± 100 (34,705-33,947 cal yr BP), and a δ13C value of −8.99‰, which indicates a generalist diet (BA = 0.96) with similar proportions of C3 (pi = 57%) and C4 (pi = 43%) plants consumed. The stereomicrowear results also suggests a mixed diet, although the high values of scratches could be associated to the significant consumption of grasses. Coarse features on the orthodentine surface indicate possible ingestion of exogenous grit due to the behavior of foraging close to or at the ground. The generalist behavior corroborates previous studies from other localities of the BIR. E. laurillardi from midwestern Brazil possibly consumed higher proportions of shrub/tree foliage, whilst in northeastern Brazil it probably had a dominant diet of C4 herbaceous plants. The distinct feeding behavior is a consequence of different climatic and environmental conditions between these regions during late Pleistocene. Our integrative study was efficient to improve the understanding about the paleoecology of this emblematic ground sloth that inhabited midwest region of the BIR during the late Pleistocene, but additional work is needed for more detailed interpretations.