50 million years AP

At the end of the Lentocene epoch, Antarctica is completely unrecognizable from our present: the Earth is facing a hothouse period, causing a drastic increase in biodiversity at higher latitudes. This condition was probably caused by the development of massive volcanic hotspots, which have increased greenhouse gas in the atmosphere. Antarctica has never been so biodiverse since the Eocene.
Rainfalls are more abundant than in the past, creating a new plant association in the Ronne gulf, the mossy forest, rich in arboreal mosses and lichens. Sea levels have also slightly increased, enlarging pre-existing bays and fjords. Internal regions of the mainland and a few other territories maintain a dry climate, which creates large steppes and scrublands; the Day-Night steppe, for example, is still present.

Volcanic activity is now more frequent around the three major islands, with the creation of small volcanic islets that partially connect Weddell to Ellsworth. A second large volcanic hotspot is also emerging around the Transantarctic mountains and the Lorentz peninsula.
The Ross rift is now moving at a higher speed than in the past, increasing the size of the Green Channel, a shallow sea that separates Marie Byrd from Polarica, with a minimum width being around 350 km (220 miles).