Abstract:The Quaternary fossil record of Águas de Araxá (QAA) is represented mainly by an accumulation of skeletal elements of several sizes, which are assigned to a population of Stegomastodon waringi. We analyzed 97 molars according to the wear stages of Simpson and Paula-Couto (1957), and developed a morphometric wear index. The population structure (proportion of immature, subadult, adult, mature adult and senile adult individuals) was identified, and these five age classes were compared to those of extant elephant… Show more
“…The QAA N. platensis had been previously recognized as a single population (Simpson and Paula Couto, 1957;Mothé et al, 2010) and its age was established by dating a single tooth (DGM104-M) and its associated sediment, representing the dating for the entire population. This N. platensis tooth is currently housed at the paleontological collection of Departamento Nacional de Produção Mineral, Rio de Janeiro State, Brazil.…”
Section: Methodsmentioning
confidence: 99%
“…Gomphotheres fossils have been found in almost all Brazilian states, but the Quaternary of Águas de Araxá (QAA) outcrop is noted for its great abundance of dental and postcranial fossils of N. platensis (Simpson and Paula Couto, 1957;Mothé et al, 2010). Previous studies suggested that the gomphothere remains from the QAA outcrop represents a single N. platensis population (Simpson and Paula Couto, 1957;Mothé et al, 2010). These papers are the basis for several other studies that investigated aspects of the taphonomy and paleoecology of South American gomphotheres (e.g.…”
“…The QAA N. platensis had been previously recognized as a single population (Simpson and Paula Couto, 1957;Mothé et al, 2010) and its age was established by dating a single tooth (DGM104-M) and its associated sediment, representing the dating for the entire population. This N. platensis tooth is currently housed at the paleontological collection of Departamento Nacional de Produção Mineral, Rio de Janeiro State, Brazil.…”
Section: Methodsmentioning
confidence: 99%
“…Gomphotheres fossils have been found in almost all Brazilian states, but the Quaternary of Águas de Araxá (QAA) outcrop is noted for its great abundance of dental and postcranial fossils of N. platensis (Simpson and Paula Couto, 1957;Mothé et al, 2010). Previous studies suggested that the gomphothere remains from the QAA outcrop represents a single N. platensis population (Simpson and Paula Couto, 1957;Mothé et al, 2010). These papers are the basis for several other studies that investigated aspects of the taphonomy and paleoecology of South American gomphotheres (e.g.…”
“…Following this idea, the biomass of herbivore communities is closely regulated by food availability (i.e. habitat's carrying capacity; see a study with African ungulates in Fritz and Duncan, 1994) and, in accordance with Mothé et al (2010), the family structure of Notiomastodon is analogous to those from current African elephants (Loxodonta africana). Also, Thomas et al (2008) show that summer home range (environmental requirements) of current African elephants is four times wider than its winter one.…”
The late Quaternary extinctions have been widely debated for a long time, but the varying magnitude of human vs. climate change impacts across time and space is still an unresolved question. Here we assess the geographic range shifts in response to climate change based on Ecological Niche Models (ENMs) and modeled the timing for extinction under human hunting scenario, and both variables were used to explain the extinction dynamics of Proboscideans during a full interglacial/glacial cycle (from 126 ka to 6 ka) in South America. We found a large contraction in the geographic range size of two Proboscidean species studied (Cuvieronius hyodon and Notiomastodon platensis) across time. The largest contractions of their geographical ranges occurred in the northern part of South America, where we previously reported no evidence of coexistence among earliest humans and non-sloth megafauna, including Proboscideans. Our results herein support a strong effect of climatic changes on geographical range dynamics of Proboscideans throughout late Quaternary, although this does not fully support climate change as the single cause of their extinctions. We show that both Proboscideans were narrowly distributed on scattered patches of suitable habitats (i.e., refugia) around 11 ka, period in which the earliest humans potentially arrived in South America, increasing the population density thereafter. Under this overall unsuitable climatic condition at 11 ka, both Proboscideans would be extinct after around 550 years of human hunting, but if climatic conditions were suitable like in Last Glacial Maximum (LGM), the time-for-extinction would be at least 3 times longer under the same human hunting pressures. Thus, our findings support the "Broken Zig-Zag" model and show that South American Proboscideans might have been completely extinct due to human impacts during periods of climate crisis. We conclude, in agreement with an increasing body of evidence in the recent literature, that the late Quaternary megafaunal extinction event was the result of additive effects from different stressors, and that the relative magnitude of these impacts vary across space and time. Indeed, climate changes set the place where the Proboscideans were extinct in South America, whereas the humans set the time of these extinctions.
“…Width reaches 75 mm at the level of the third raw, 67 mm at the fourth and 47.5 mm at the heel.This gomphothere had the mass of an Asian elephant. It is reported from several Brazilian sites such as Águas de Araxá (Minas Gerais) (Mothé et al, 2010), Lagoa São Vitor (Piauí) and Lagoa Uri de Cima (Pernambuco state) (Faure & Guérin, 2013, Figures 3 and 4). Recently, Mothé et al (2020) observed some traces of projectile points on a Gomphothere calf skull from Lapa do Caetano (Lagoa Santa region, Minas Gerais state).…”
Northeastern Brazil has thousands of wetland fossiliferous deposits with megafauna and, in some cases, associated lithic artifacts. The timing of the arrival of humans in South America and the extinction of megafauna is still debated and these sites contribute both to this discussion and to the reconstruction of the Late Pleistocene and Holocene paleoenvironment. Lagoa do Quari, 40 km south of São Raimundo Nonato, Piauí state, is a marsh deposit in the present semiarid caatinga environment, excavated by an interdisciplinary team in 2002–2003. This paper presents the archaeological, palaeontological, geological, chronological, stratigraphical and palynological results and their implications for the Quaternary of northeastern Brazil. The site has a rich megafaunal bonebed at the bottom, dominated by Eremotherium giant sloth remains with poor biodiversity, and a sandy‐silty deposit at the top; two 14C dates constrain this latter layer to 9,944–9,557 and 6,308–6,177 cal. years BP and the associated rich lithic industry of quartz and chert shows a technical continuity throughout the Holocene in the region. Palynology describes an open landscape with periodic wet phases, which could explain the richness of the archaeological occurrences in Holocenic Brazilian prehistory. This study offers a model of interdisciplinary enquiry into the paleoenvironment and prehistory of lowland South America.
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