EVOLUTIONARY PROCESSES IN THE FOSSIL RECORD: PATAGONIA AS A CASE STUDY (Invited Presentation)

Patagonia is the southernmost area of South America comprising the landmasses between 37° and 55° S. This region has an intense geological history from the beginning of the breakup of Gondwana, accentuated during the Cenozoic when it separated from Antarctica until the completion of the rising of the Andes. Major geotectonic and climatic changes that affected Patagonia include its separation from Antarctica, the establishment of the Circumpolar and Humboldt Currents, the Pacific and Atlantic ingressions, the uplift of the Andes, and the “Arid diagonal” development.

This complex tectonic activity coupled with intense climatic changes turned Patagonia into a natural floristic laboratory in which examples of biogeographic and evolutionary processes were recorded. Such events include diversification, speciation, extinctions, disjunctions, co-evolution, expansions and retraction of geographic areas. In this presentation, we will present iconic examples of these evolutionary processes that occurred in Patagonia in relation to the geological and climatic variables. Examples of evolutionary processes comprise the extinction of Casuarianaceae, Eucalyptus, and Agathis, the retraction of Arecaceae and Ulmaceae, the diversification of Nothofagus, the typical disjunction of Winteraceae, Cunoniaceae, and Araucaria, the expansion of the grass steppe, the co-evolution of Nothofagaceae and Misodendraceae, and the speciation of Proteaceae.