Fossil leaves of subtropical lineages in the Eocene–?Oligocene of southern Patagonia

Abstract

Here I describe and illustrate 19 leaf morphospecies from the Paleogene Río Turbio Formation, Santa Cruz Province, Argentina. They were referred to the extant tropical and subtropical families Lauraceae (9 morphospecies), Malpighiaceae (1 morphospecies), Vitaceae (2 morphospecies), Anacardiaceae (2 morphospecies) and Sapindaceae (5 morphospecies). These taxa were recorded throughout the unit, but they are more abundant in the lower member of the Río Turbio Formation. The observed decreasing trend in megathermal taxa throughout the unit indicates the beginning of the flora turnover that characterized Patagonian ecosystems from the Late Eocene onwards and it is in agreement with the marked global cooling trend of the terminal Paleogene.