Lost in the collections. A critical re-appraisal on Equus major provides a new perspective on the paleobiogeography of the Plio-Pleistocene European equids and on the Equus Datum

Abstract

Despite its description at the end of the XIX Century, the alpha-taxonomy, paleobiogeography and biochronology of Equus major remains obscure and ill-defined, leaving a gap of knowledge in the evolutionary history of the Eurasian Palearctic Early Pleistocene Equus species. In this contribution, we describe the Early Pleistocene E. major samples from Pardines and Senèze, providing a comparison by multivariate and statistical analyses with the Early and Middle Pleistocene European stenonid fossil Equus species. Moreover, we explore the paleoecology of E. major by mesowear and body mass estimates, comparing its palaeobiogeographic distribution with European paleoclimatic conditions during the Early Pleistocene. Our outcomes help to clarify the fossil record of E. major, leading to our interpretation that it was the largest Early Pleistocene Equus in Europe, it had a browse-dominated to mixed-feeding diet and was well adapted to humid and forested parts of Europe during the earliest Pleistocene. Eventually, the comparison of our paleoclimatic map with the European fossil record provides new insights in understanding their distribution in time and space during the Early Pleistocene, allowing to clarify details surrounding the Equus Datum in Western Eurasia.