Great inter-American exchange
The great exchange inter-American was an important event paleozoogeographic during which terrestrial fauna and of fresh water migrated of North America via the Central America towards the South America and vice versa, when the volcanic isthmus of Panama was drawn up with the top of the sea level and acted as footbridge between the two continents. The migration culminated in a spectacular way there are approximately 3 million years (during the Piacenzien, first half of higher Pliocène).
That led to the connection of the écozone néotropicale and the nearctic écozone. Its most spectacular effect was on the zoogeography of the mammals but it also gave an opportunity to the apterous birds, the arthropods, the reptiles, and the Amphibians and even to fresh water fish to migrate.
South American fauna during major the part of Cenozoic was characterized by the presence of endemic mammals which one nowhere found elsewhere on the sphere, composed primarily of marsupials and xenarthra (armadillos, fourmilliers, and of lazy like the lazy terrestrial giant or mégathérium), and various groups of ongulés South American: notongulés (" ongulés of Sud"), litopternes, astrapotheres, and pyrotheres. The marsupials present in South America included/understood didelphimorphes (opposums and related), but also of many predatory forms existed, like borhyaenidés and the marsupial with tooth of Thylacosmilus saber. The predatory marsupials coexisted with the large predatory ones like the terrible apterous bird Phorusrhacidé. Notongulés and litopternes presented strange forms like Macrauchenia, small a litopterne with a horn. The two groups started to evolve/move with the Paleocene inferior, probably starting from the Condylarthra, diversified, declined before the great exchange, and died out at Pleistocene. The pyrotheres and astrapotheres were not less strange but they were diversified and disappeared well before the great exchange.
Fauna mammalienne of North America was typically boréoeuthérienne.
- Colombian Exchange
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