20 million years AP
Antarctica's climate starts to diversify after 20 million years: internal areas are still influenced by the Big White, maintaining a tundra ecosystem, but coasts have become warm enough to develop the first antarctic forest, called the austral forest. This new habitat has become rapidly a new refuge for a lot of antarctic animals, that finally started to specialize significantly. Wood biomass increase was very relevant for insects like beetles, but also indirectly for a large number of insectivorous birds. Freshwater ecosystems also have drastically increased their range, with the appearance of the first riparian forests. With the glacial retreats, lots of large glacial lakes have formed.
The ongoing sea rise starts increasing the distance between Polarica and the other large islands, causing an increase in endemisms. Ellsworth and Weddell islands still maintain a decent connectivity thanks to steppingstone corridors and due to their proximity, while Marie Byrd remoteness makes any potential land bridge extremely filtering.
