Permian

The Permian is the last period of the Paleozoic Era, spanning roughly 298.9 to 251.9 million years ago. The name derives from the Perm region of Russia, where rocks of this age were first studied. The period is divided into three epochs: the Cisuralian (Early Permian), Guadalupian (Middle Permian), and Lopingian (Late Permian).

During much of the Permian, the continents assembled into the supercontinent Pangaea, producing vast interior deserts and pronounced climatic seasonality. Seaways along the margins varied with sea level changes. The later Permian saw a trend toward aridity at low latitudes, though tropical and subtropical regions remained biologically productive in some areas. Flora was dominated by gymnosperms, including conifers and other seed plants.

Ecologically, terrestrial life was led by therapsids, a group of mammal-like reptiles, alongside various reptiles, amphibians, and insects. Forests of conifers and other gymnosperms provided habitats, while coastal and inland seas supported diverse marine faunas, including brachiopods, mollusks, echinoderms, and ammonoids.

The Permian ended with the Permian–Triassic extinction event, about 251.9 million years ago, the largest mass extinction in Earth history. It eradicated an estimated 90–96% of marine species and about 70% of terrestrial vertebrate genera, likely driven by a combination of vast Siberian Traps volcanism, rapid climate warming, ocean anoxia, and disruptions to the carbon cycle. Recovery after the boundary was slow, giving way to the rise of the Triassic ecosystems.