middlePermian

The middle Permian, also referred to as the Guadalupian, is a subdivision of the Permian period that spans roughly from 272 to 259 million years ago. It sits between the Early Permian (Cisuralian) and the Late Permian (Lopingian) and marks a middle phase in the assembly of continental landmasses and the evolution of marine and terrestrial ecosystems. The name Guadalupian derives from the Guadalup Mountains in Texas, where representative fossil-bearing rocks were studied.

Stratigraphically, the middle Permian is divided into three ages (or stages): Roadian, Wordian, and Capitanian. These subdivisions are based on distinct fossil assemblages and sedimentary records, including changes in fusulinid and ammonoid communities, as well as shifts in carbonate and clastic sedimentation in episodic seaways.

Paleogeography during the middle Permian was dominated by the supercontinent Pangaea, with climate ranging from arid interior regions to warm, seasonal coastal zones. Widespread shallow seas and epicontinental basins persisted in some areas, while others experienced arid or semi-arid conditions. Oceanic circulation and sea levels fluctuated, influencing marine biodiversity and reef development.

Biologically, the middle Permian saw continued diversification of marine invertebrates, including abundant brachiopods, bryozoans, fusulinids, and ammonoids, as well as reef-building organisms. Terrestrial ecosystems produced diversification among therapsids and other synapsids, along with evolving plant communities in Gondwanan regions.

The middle Permian ended with a notable biotic turnover at the Guadalupian–Lopingian boundary, including losses in several marine and terrestrial groups. This end-mid Permian event preceded the more extensive end-Permian mass extinction at the close of the Permian, shaping the trajectory of life in the late Paleozoic.