Potential historically intertropical stable areas during the Late Quaternary of South America

Abstract

South America is a pivotal paleontological setting for Late Quaternary megafaunal research. Nonetheless, its paleobiogeography and paleoecology, and the causes for the recent extinction of megafauna in the Late Pleistocene/Early Holocene are not yet fully understood. This study aimed to investigate the potential geographical distribution and historically intertropical stable areas (HISAs) of South American megafauna. We generated maps using Paleo-Species Distribution Models for 12 megafaunal taxa (11 herbivores and one carnivore) during interglacial and glacial periods in the Late Quaternary: 120 and 21 ka. Our models, together with isotopic data, show that the HSIAs occurred mainly in low-altitude plains (<1000 m) and were superimposed on seasonal dry forest biomes. We propose the occurrence of two HSIAs: the West Intertropical Region and the Brazilian Intertropical Region, the latter being redefined. We suggest that the Brazilian Intertropical Region is much smaller than previously proposed, but was still a key zoogeographical region for megafauna in South America during the Late Pleistocene.