Isotopic paleoecology (δ13C, δ18O) of Late Quaternary megafauna from Mato Grosso do Sul and Bahia States, Brazil

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.…”

“…The isotopic analyses in teeth of Eremotherium from several localities across northeastern to central-western Brazil (Figure 6A-B), have shown a wide diet range, from pure C4 to C3-dominated, but mostly mixed feeding (Dantas et al, 2013;2017;França et al, 2014;Silva, 2015). Despite few analyzed specimens from central-western Brazil, these seem to indicate predominance of C3 plants in the diet towards higher latitudes (Pansani et al, 2019;Oliveira et al, 2020). Being a species of tropical origin, possibly from southeastern-southern North America (Cartelle & De Iuliis, 2006), Eremotherium may have originally fed on arboreal vegetation but was also capable of incorporating significant amounts of C4 plants and C3 grasses in drier environments, thus seems to have been more generalist than Megatherium.…”

“…The teeth of xenarthrans are formed mostly of dentine, regarded as more prone to diagenetic modification compared to enamel because of its higher organic content, lower hardness, and smaller crystallites (MacFadden et al, 2010), thus making enamel the preferred material for isotope analysis. Nevertheless, isotopic studies on teeth of extinct sloths have been performed, showing that such analysis is feasible on dentin as well (Kohn et al, 2005;Ruez, 2005;Domingo et al, 2012;França et al, 2014;Silva, 2015;Dantas et al, 2017;Larmon et al, 2019;Pansani et al, 2019;Oliveira et al, 2020;Tomassini et al, 2020). The teeth of megatheriid sloths are prismatic, hypsodont, with subrectangular to subtriangular transverse outline and bilobate occlusal surfaces formed by transversal sharp crests separated by a deep valley (Owen, 1861;Spillmann, 1948;Sicher, 1953;Cartelle & De Iuliis, 1995;Vizcaíno, 2009).…”

“…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.…”

δ<sup>13</sup>C values in stalagmites from tropical South America for the last two millennia

“…Measurements of carbon isotope (δ 13 C) ratios are essential for (paleo)environmental studies, such as those regarding the carbon cycle, past food consumption by pre-historic societies, paleo-vegetation reconstructions, soil dynamics, aspects regarding animal migration and food consumption, etc. (Rayner et 40 al., 1999;Calo and Cortés, 2009;Pansani et al, 2019;Novello et al, 2019). However, δ 13 C values of speleothems are generally considered difficult to interpret and, in most cases, are not reported in isotopic studies based on speleothems.…”