Isotopic paleoecology of the Pleistocene megamammals from the Brazilian Intertropical Region: Feeding ecology (delta C-13), niche breadth and overlap

摘要

The extinct megamammals Eremotherium laurillardi (weight 6550 kg), Notiomastodon platensis (w = 6000 kg), Toxodon platensis (w = 3090 kg), Valgipes bucklandi (w = 980 kg) and Equus (Amerhippus) neogaeus (w = 370 kg) are recorded for the late Pleistocene of the Brazilian Intertropical Region. In order to evaluate the isotopic paleoecology (feeding diet, niche breadth and overlap) of these species,C-14 dates, delta C-13 and delta O-18 analyzes were performed. Our results suggest that E. laurillardi (mu delta(3C) = -435 +/- 2.87%o; mu B-A = 0.77 +/- 0.25), T platensis (mu C-13 = -5.74 +/- 4.80%o; mu B-A = 0.57 +/- 0.40) and N. platensis (mu delta C-13 = -1.17 +/- 2.76%o; mu B-A = 0.56 +/- 0.20) were mixed feeders with a wide niche breadth, while E. (A.) neogaeus (mu delta C-13 = 0.73 +/- 1.19%o; mu B-A = 0.38 +/- 0.22) was a grazer, and V. bucklandi (delta C-13 = -10.17%o; B-A = 0.13) was a specialist browser. A narrow niche overlap occurred between V. bucklandi and the species that fed principally on C-4 plants (>70%; O = 0.24-0.43). In contrast, there was a high niche overlap between E. neogaeus and N. platensis (O = 0.75) and between E. laurillardi and T. platensis (O = 0.86). Therefore, E. laurillardi was probably a key species in this Pleistocene community due to its high body weight and wide niche breadth, suggesting that E. laurillardi was a great competitor for resources in the BIR. (C) 2017 Elsevier Ltd. All rights reserved.