Other forms: Permians
The Permian, the final period of the Paleozoic era, started around 299 million years ago. It ended with the "Great Dying," the greatest mass extinction in Earth's history, about 252 million years ago.
During the Permian, most of Earth's land merged into the supercontinent Pangea, which was surrounded by the global ocean Panthalassa. This created vast deserts and extreme climates in the land's interior. The Permian saw the rise of synapsids, mammal-like reptiles such as dimetrodon, which had a large sail of elongated spines along its back, probably used to regulate its temperature. The extinction event at the end of the Permian was likely triggered by volcanic eruptions, along with climate change and ocean acidification.