Neotropic - History

History

South America was originally part of the supercontinent of Gondwana, which included Africa, Australia, India, New Zealand, and Antarctica, and the Neotropic shares many plant and animal lineages with these other continents, including marsupial mammals and the Antarctic flora.

After the final breakup of the Gondwana about 110 million years ago, South America was separated from Africa and drifted north and west. Much later, about two to three million years ago, South America was joined with North America by the formation of the Isthmus of Panama, which allowed a biotic exchange between the two continents, the Great American Interchange. South American species like the ancestors of the Virginia opossum (Didelphis virginiana) and the armadillo moved into North America, and North Americans like the ancestors of South America's camelids, including the llama (Lama glama), moved south. The long-term effect of the exchange was the extinction of many South American species, mostly by outcompetition by northern species.