This chapter offers a broad-stroke perspective on changing faunas and habitats of South America over the past 250 (million years) Ma. The observations are based primarily on the Patagonian fossil record, since it is the only region of the continent where nearly all major time intervals are represented. The excellent record in Patagonia is the result of fortuitous geological and climatic factors. For much of the Cenozoic, parts of Patagonia gradually accumulated water- and wind-borne sediments, conditions highly suitable for the preservation of teeth, bones, tracks, and other evidence of past...

This chapter offers a broad-stroke perspective on changing faunas and habitats of South America over the past 250 (million years) Ma. The observations are based primarily on the Patagonian fossil record, since it is the only region of the continent where nearly all major time intervals are represented. The excellent record in Patagonia is the result of fortuitous geological and climatic factors. For much of the Cenozoic, parts of Patagonia gradually accumulated water- and wind-borne sediments, conditions highly suitable for the preservation of teeth, bones, tracks, and other evidence of past life. Some of these sediments were sands and silts derived from the erosion of topographically higher areas, whereas others were ashes from volcanic eruptions. Water and wind erosion in Patagonia continuously expose new fossils. The chapter recognizes five main phases in the evolution of South American mammal faunas.