Isotopic paleoecology (δ13C, δ18O) of late Quaternary herbivorous mammal assemblages from southwestern Amazon

The paleoecology of Pleistocene giant megatheriid sloths: stable isotopes (δ13C, δ18O) of co-occurring Megatherium and Eremotherium from southern Brazil

“…The δ 13 C value of this individual is similar to specimens from the Amazon and central-western Brazil (Pansani et al, 2019;Oliveira et al, 2020;Asevedo et al, 2021), and intermediate between closed canopy forest and forest gaps/ open woodland (Secord et al, 2008), thus it suggests foraging in riparian forests and neighboring open woodlands and grasslands, similar to the habit inferred for Megalonyx sloths from New Mexico (McDonald & Morgan, 2011). According to Oliveira et al (2002), riparian forests were present along Pessegueiro Creek based on the type of vegetal remains (tree trunks and leaves) associated with the sloth fossils found in the channel deposits.…”

“…Because the levels (pCO 2 ) and isotopic composition (δ 13 C CO2Atm ) of atmospheric CO 2 have varied throughout the Cenozoic (Marino et al, 1992;Tipple et al, 2010), the δ 13 C of the plants also changed, but this variation is difficult to assess because most fossil records do not have associated numerical ages. Despite the lack of numerical ages in the analyzed specimens, the fossil assemblage of Chuí Creek represents some 190 kyrs (~220-30 ka) between the Middle and Late Pleistocene (Lopes et al, 2020;2021), therefore this interval is considered here for reference. The δ 13 C CO2Atm during that interval exhibits marked variations (Figure 2), and although a mean value of -6.5‰ is in general considered for the last glacial period (112.5 to 11.7 ka), during warmer (interglacial and interstadial) phases the values were more positive, and during stadial (cold) phases were more negative, reaching an average of -7.1‰ (Marino et al, 1992;Tipple et al, 2010).…”

“…Despite some anatomical differences in skull and jaw bones, both species share morphological features of browsers (narrow muzzle) and grazers (hypsodont teeth, Figure 6. A, distribution of fossils of Megatherium americanum and Eremotherium laurillardi with associated isotopic data found across South America; records of Eremotherium without isotopic data are also shown (from Paula Couto, 1979;Cartelle & De Iuliis, 1995;Rossetti et al, 2004;Praderio et al, 2005;Martinelli et al, 2012;Bocherens et al, 2017;Lopes & Pereira, 2019;Pansani et al, 2019;Domingo et al, 2020;Oliveira et al, 2020;Tomassini et al, 2020;Asevedo et al, 2021). B, Comparative δ 13 C data of both megatheriids across the continent.…”

Ice Age megafauna rock art in the Colombian Amazon?

“…In South America, Notiomastodon platensis had a more widespread distribution than Cuvieronius hyodon, which was largely restricted to the Andean region, but with similarly mixed diets (i.e. woodland, mixed, grassland) [42][43][44]. Despite overlapping geographical distributions in the mid and northwestern regions of South America, these South American gomphotheres have rarely been recorded in the same locality [45,46].…”

Paleodiet of Lamini camelids (Mammalia: Artiodactyla) from the Pleistocene of southern Brazil: insights from stable isotope analysis (δ13C, δ18O)

“…This analysis is based on the premise that the organism's isotopic composition changes in predictable ways, following the biogeochemical processes of the trophic web (Peterson and Fry 1987). In paleontological studies, the most common isotopes are carbon and oxygen, which can be measured in the inorganic fraction (biological apatite) of skeletal remains (e.g., Yann et al 2016; Ma et al 2019; Domingo et al 2020; Asevedo et al 2021). The isotopic ratios of oxygen (δ 18 O) in inert tissues are mainly related to water ingested by drinking and eating (Luz et al 1984; Kohn 1996).…”