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Among the extinct cervids of the Pleistocene in South America, Morenelaphus has the most abundant fossil record and the broadest geographic distribution. However, the paleoecology of Morenelaphus is poorly known, especially its dietary patterns; thus, this study aims to recognize the feeding habits of this extinct cervid through analysis of microwear. The microwear analysis indicated a mixed-feeder diet for Morenelaphus ; both high pit values and frequency of individuals with low number of fine scratches indicated the consumption of grasses, possibly including grit (siliciclastic sediment), ingested during feeding. Also, our results suggest that Morenelaphus possibly went extinct at the Pleistocene-Holocene transition as a result of climate/environmental changes and/or a physiological/nutritional crisis.

This work identifies and interprets taphonomic features of the deer fossil assemblage recovered from the Gruta do Urso cave, located in Tocantins State, Northern Brazil. Consequently, its results shed light on the origin of the vertebrate assemblages in cave deposits and paleoecological aspects of Quaternary deer of northern Brazil. The cervid fossil accumulation of the Gruta do Urso cave includes individuals of three species that died outside the cave and, then, underwent disarticulation and weathering during a time span between one and five years. During the necrolysis, they experienced scavenging by large-sized felids and small-sized canids. Then, the disarticulated remains and a mummified hindlimb were transported into the cave by multiple events of low-energy hydraulic flows. Inside the cave, some specimens experienced exposure on the water table and incrustation. The biostratinomic data suggest the taphonomic history of deers around Gruta do Urso cave occurred in arid conditions.

The extinction of the Quaternary megafauna stands out among the evolutionary history of Cenozoic mammals. In South America, nearly 80% of the megamammals went extinct, including the native ungulates Macrauchenia patachonica and Xenorhinotherium bahiense. Little is known about the causes of the macraucheniids’ extinction and their paleobiology. Here, we have reconstructed the dietary habits of M. patachonica and X. bahiense using enamel microwear and occlusal enamel index analyses, and also inferred their niches using species distribution modeling and stable isotope paleoecology, in addition to enamel microwear and occlusal enamel index data. We found that both macraucheniids had grazer-feeding habits, although their environmental requirements were different. M. patachonica could live in colder temperatures and arid, subtropical/temperate ecosystems, while X. bahiense was adapted to warmer temperatures and more humid, semi-arid tropical environments. Thus, despite similar feeding habits, these macraucheniids had distinct environmental requirements and ecological niches, which might explain the disjunction in the South American records.

During paleontological surveys conducted in 2013 and 2014 in Quaternary deposits from the Gruta do Urso cave, Tocantins State, nine isolated teeth and five postcranial elements of Equus neogeus were recovered. Absolute datings indicate that E. neogeus inhabited the surroundings of Gruta do Urso cave during the Last Glacial Maximum. The specimens probably represent very young individuals that died outside the cave, were weathered prior to the final burial, with ontogenetic and taphonomic similarities. Herein, we report the first scavenger interaction of ursids and equids in the South American fossil record.