Megafauna-human interaction in central Mexico 35,000 years ago? Late Pleistocene bones and artifacts from Cedral, San Luis Potosí

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During the past 15 kyr Mexican ecosystems were subject to rapid climate fluctuations resulting in spatially and temporally changing biodiversity patterns. In North-Central Mexico, this is influenced to the north-south orientation of both the Sierra Madre Oriental and Occidental mountain ranges. The plains between them allowed for a north-south migration of biota. In contrast the Trans-Mexican Volcanic Belt running in an East-West direction hindered the biotic interchange between North and South America. The fossiliferous sediments between the Sierras are perfect for analyzing fluctuations of biodiversity, environment and climate. Mexico also has a long history of peopling that is proved as early as ca. 13,000 kyr.In September 2019, a contact with an employee of the Santa Maria Silver Mine in Villa de la Paz, San Luis Potosí, Central Mexico, resulted in a scientific weekend meeting combined with a one day field trip to the Amapola Ranch at the town of Cedral. The local outcrops are full of fossils of Late Pleistocene age and prove an unusual biodiversity. Fossil wood and charcoal nests interpreted as hearths, associated with artifacts, were dated to about 35,000 years bp.During the past decade, an interdisciplinary investigation of localities at Cedral has been carried out by an archaeology work group of the University of San Luis Potosí. During the weekend meeting in Villa de La Paz, the UASLP it turned out that most of their results are based on doubtful methods and that the dating produced by a state institution has never been confirmed nor have bone samples been dated. The proposed project is based on scientific two pilot excavations in an extremely fossiliferous pit that has not been investigated. Based on the results of these excavations with respect to biodiversity, geological age and environmental proxies we will be able to draw conclusions on the faunal and environmental changes across the Pleistocene-Holocene boundary in the Cedral region and compare these data with those of other coeval localities. We will also search the bones for scratch marks and discuss the mass extinction of megafauna in the context of environmental changes and humans settlement. Additionally we have access to an artifact collection containing more than 17,000 specimens, amongst them large un-fluted blades intermediate between Solutrean and Clovis style. The exact provenance of these blades is known and should be sediment sampled. Of special interest is the correlation between the artifacts found at Amapola and the material in the collection.We are aware that the funding requested here will only allow us to establish new environmental for a future larger German-Mexican joined project.