Doing the Time Warp again: Electron Spin Resonance dating reveals oldest numeric age for Notiomastodon platensis Ameghino, 1888 (Mammalia, Proboscidea)

Abstract

Here we used Electron Spin Resonance (ESR) dating methods on seven fossil specimens to update the temporal and geographic distributions of the Quaternary proboscidean Notiomastodon platensis Ameghino 1888, from Córdoba Province, Argentina. While abundant in the Late Pleistocene/Early Holocene South American fossil record, the knowledge about the Early-Middle Pleistocene records of this proboscidean is scarce due to limited numeric datings data. ESR results reveal numeric ages ranging from 560 ± 40 to 47 ± 7 ka, placing the species within the Ensenadan to Lujanian stages of the Pleistocene (Chibanian to Late Pleistocene). The Ensenadan record represents the oldest numeric age of Notiomastodon platensis in South America. The study highlights the importance of numeric dating in addressing the geochronological data gap for South American megafauna and reveals the multiple environments that Notiomastodon platensis inhabited during Quaternary, suggesting slow vertical migrations in response to climatic changes, with mountainous regions of Cordoba province serving as refuges. The need for further numeric datings is emphasized in this study, to improve our understanding of the evolutionary history and extinction drivers of South American proboscideans during the Quaternary.