Fossil woods from late Pleistocene sediments from El Palmar Formation, Uruguay Basin, Eastern Argentina

Abstract

The Santa Ana fossiliferous locality (Entre Ríos, Argentina) of the El Palmar Formation is located in the southernmost part of the Uruguay Basin, in eastern Argentina. It contains evidence of a late Pleistocene paleoflora, consisting mainly of fossil woods. These remains were studied and are described based on anatomically preserved secondary xylem. Two new morphospecies of Mimosoxylon Müller-Stoll et Mädel 1967 and Prosopisinoxylon Martínez 2010 are described, as well as two new morphogenera, related to Holocalyx Micheli, 1883 and Amburana Schwacke et Taub. 1894. These two new morphogenera represent the first recorded fossil wood with affinity to Faboideae from the Uruguay Basin. Schinopsixylon heckii Lutz 1979, (Anacardiaceae) was also recognized. These fossil woods are discussed here in terms of floristic composition and palaeoclimatic requirements. The morphotypes described here, as well as previously recorded ones from the Uruguay Basin, increases our understanding of floral diversity during the late Pleistocene in this region.