aiuto per anatomia comparata

Permian Sites

The Permian has few sites with exceptional preservation. Some exceptional arthropod specimens are known from Kansas and Oklahoma (south-central US). The Permian is best known for its vertebrate fossils .

Three important areas for Permian vertebrate fossils are the Early to middle Permian equatorial Red Beds of Texas and Oklahoma, the middle to late Permian Kazanian and Tatarian zones on the Russian platform, and the Late Permian Karoo series (Lower Beaufort) of southern Africa.

The Red Beds are full of the fossil remains of pelycosaurs like the finbacks like Dimetrodon, which was clearly the dominant predator of these environments for some 20 million years. The Russian and South African sites contain the remains of many therapsids. These creatures succeeded the basal synapsids as the rulers of the land, until they in turn were supplanted by the archosaurs during the Early Triassic.