From Gondwana to the Great American Biotic Interchange: The Birth of South American Fauna

Abstract

The Great American Biotic Interchange (GABI) is one of the biggest biogeographical events, which has shaped the modern South American fauna. It refers to several migratory pulses of continental fauna between North and South America, beginning during the Miocene and continuing to the present day. It intensified during the Pliocene with the closure of the Isthmus of Panama and has been fundamental in the settling of the Neotropical and Nearctic realms as we know them today. However, this is far from being the only time that South America has been colonized or being part of a biotic exchange with other continental masses. During approximately 400 million years South America was part of the ancient supercontinent Gondwana, being connected with the other large land masses of the Southern Hemisphere. The later break-up of this supercontinent paid an enormous impact in the composition of faunas across the whole hemisphere, and the resulting extended period of South American isolation gives birth to a unique assemblage of animals and plants. This chapter aims to offer an introduction to the biogeographical events and processes that shaped the South American fauna during the Cenozoic, with an emphasis on those that took place before the GABI. It provides a broad context to understand the processes at work during the Late Pleistocene when the Pilauco site was formed and the origin of the animals that inhabited it.