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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.

The tragic fire at the National Museum (Brazil) in September 2018 caused invaluable losses to South American natural and cultural heritage. However, previous visits to the paleontological collection generated photographic and descriptive records of mammalian fossil specimens from the Pleistocene of Brazil. Thus, it was possible to redescribe and revise the taxonomy of Cervidae fossils from two important paleontological sites in the Brazilian Intertropical Region (Joao Cativo and Lage Grande). These fossils include antlers and lower teeth, and they were described and taxonomically identified by morphological comparisons with all extant and extinct South American deers. A new diversity of Cervidae was recognized, differently from that proposed in the literature, which recognized the presence of Hippocamelus sulcatus, Mazama americana, and Ozotoceros bezoarticus. Instead, the Cervidae fossils from Joao Cativo and Lage Grande sites belong to the extinct deer Morenelaphus. Although some specimens could not be identified at a specific level (Cervidae indet.), a comparative analysis of the estimated body mass pointed out the most massive deer in South America (including extinct and extant) and recognized Morenelaphus as the second heaviest. The record of these large deers with huge antlers suggests the presence of natural grasslands areas and milder climatic conditions for late Pleistocene in the Brazilian Intertropical Region. Climatic and environmental changes may have driven these large deers to extinction in the Pleistocene/Holocene transition. This study reveals an unprecedented Cervidae diversity for the Brazilian Intertropical Region, emphasizes the relevance of dental features, together with antlers morphology, in taxonomic studies of Cervidae, and also highlights the importance of South American natural heritage in the retrieving of knowledge and new scientific discoveries through collection specimens.

As grutas da Provincia Espeleologica Bambui, em Aurora do Tocantins, norte do Brasil, tem revelado importantes acumulacoes fossiliferas atribuidas ao intervalo Pleistoceno Superior–Holoceno. Recentemente, os primeiros registros fosseis da Gruta Tacho de Ouro foram recuperados, sendo estes atribuidos aos taxons Tayassu pecari, Cervidae indet., Odocoileus virginianus, Mazama sp., Palaeolama major, Tapirus sp., Coendou sp. e Catonyx cuvieri. A presenca de taxons extintos entre os achados sugere que a tafocenose pode ser atribuida ao intervalo Neopleistoceno–Holoceno. Informacoes quanto aos habitats reconhecidos para os taxons encontrados na caverna indicam um ambiente afetado por variacoes climaticas neste intervalo, corroborando com a hipotese da nao contemporaneidade dos especimes. A ocorrencia de O. virginianus na Gruta Tacho de Ouro representa o registro mais meridional para a especie no Brasil. A analise tafonomica indica que os animais provavelmente pereceram externamente a gruta, em um clima arido e, posteriormente, foram carreados para o interior da caverna por um fluxo hidraulico de baixa energia, onde foram rapidamente soterrados entrando em contato com o nivel vadoso da gruta. A analise quanto aos vestigios de alimentacao (Fodinichnia) observados nos fosseis apontou que tais danos estao associados a predacao ou necrofagia realizada por carnivoros. Palavras-chave: Provincia Espeleologica Bambui, Aurora do Tocantins, Intervalo Pleistoceno–Holoceno. DOI: http://dx.doi.org/10.4072/rbp.2017.2.05

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.

The drivers of the global Quaternary megafaunal extinction are constantly being updated and discussed. Most paleoarchaeological sites in South America with proboscideans and humans in association are considered as clear killing sites, an interpretation that might not consider their taphonomic aspects and neglect other ecological interactions. Here we describe a unique example of megafaunal killing by humans in South American, a skull of a young Notiomastodon platensis from Brazil with an artifact embedded in its rostral area. This fossil proboscidean is from Lagoa Santa Karst, the homeland of some of the oldest evidence for humans in South America, the Lagoa Santa culture. The late Pleistocene/early Holocene deposits from Lagoa Santa may record a bottleneck ecological process for megafaunal populations, and the hunting activity of past humans perhaps played an important role in Notiomastodon platensis extinction.

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.