Lopingian

The Permian
Permian is a geologic period and system which spans 46.7 million years from the end of the Carboniferous
Carboniferous Period 298.9 million years ago (Mya), to the beginning of the Triassic
Triassic period 251.902 Mya. It is the last period of the Paleozoic
Paleozoic era; the following Triassic
Triassic period belongs to the Mesozoic
Mesozoic era. The concept of the Permian
Permian was introduced in 1841 by geologist Sir Roderick Murchison, who named it after the city of Perm. The Permian
Permian witnessed the diversification of the early amniotes into the ancestral groups of the mammals, turtles, lepidosaurs, and archosaurs. The world at the time was dominated by two continents known as Pangaea
Pangaea and Siberia, surrounded by a global ocean called Panthalassa. The Carboniferous
Carboniferous rainforest collapse left behind vast regions of desert within the continental interior.[6] Amniotes, who could better cope with these drier conditions, rose to dominance in place of their amphibian ancestors. The Permian
Permian (along with the Paleozoic) ended with the Permian– Triassic
Triassic extinction event, the largest mass extinction in Earth's history, in which nearly 90% of marine species and 70% of terrestrial species died out.[7] It would take well into the Triassic for life to recover from this catastrophe.[8] Recovery from the Permian– Triassic
Triassic extinction event was protracted; on land, ecosystems took 30 million years to recover.[9]

Contents

1 Discovery 2 ICS Subdivisions 3 Oceans 4 Paleogeography 5 Climate 6 Life

6.1 Marine biota 6.2 Terrestrial biota

6.2.1 Insects 6.2.2 Synapsid
Synapsid and amphibian fauna

7 Permian– Triassic
Triassic extinction event 8 See also 9 References 10 Further reading 11 External links

Discovery[edit] The term "Permian" was introduced into geology in 1841 by Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Édouard de Verneuil.[10][11] The region now lies in the Perm Krai of Russia. ICS Subdivisions[edit] Official ICS 2017 subdivisions of the Permian
Permian System from most recent to most ancient rock layers are:[12]

Lopingian
Lopingian epoch [259.8 ± 0.4 Mya - 251.902 ± 0.06 Mya]

Changhsingian (Changxingian) [254.1 ± 0.07 Mya - 251.902 ± 0.06 Mya] Wuchiapingian (Wujiapingian) [259.8 ± 0.4 Mya - 254.1 ± 0.07 Mya] Others:

Waiitian (New Zealand) [260.4 ± 0.7 Mya - 253.8 ± 0.7 Mya] Makabewan (New Zealand) [253.8 - 251.0 ± 0.4 Mya] Ochoan (North American) [260.4 ± 0.7 Mya - 251.0 ± 0.4 Mya]

Guadalupian
Guadalupian epoch [272.3 ± 0.5 - 259.8 ± 0.4 Mya]

Capitanian stage [265.1 ± 0.4 - 259.8 ± 0.4 Mya] Wordian stage [268.8 ± 0.5 - 265.1 ± 0.4 Mya] Roadian
Roadian stage [272.3 ± 0.5 - 268.8 ± 0.5 Mya] Others:

Kazanian or Maokovian (European) [270.6 ± 0.7 - 260.4 ± 0.7 Mya][13] Braxtonian stage (New Zealand) [270.6 ± 0.7 - 260.4 ± 0.7 Mya]

Cisuralian
Cisuralian epoch [298.9 ± 0.15 - 272.3 ± 0.5 Mya]

Kungurian stage [283.5 ± 0.7 - 272.3 ± 0.5 Mya] Artinskian
Artinskian stage [290.1 ± 0.7 - 283.5 ± 0.7 Mya] Sakmarian stage [295. ± 0.8 - 290.1 ± 0.7 Mya] Asselian stage [298.9 ± 0.15 - 294.6 ± 0.8 Mya] Others:

Telfordian (New Zealand) [289 - 278] Mangapirian (New Zealand) [278 - 270.6]

Oceans[edit] Sea levels in the Permian
Permian remained generally low, and near-shore environments were reduced as almost all major landmasses collected into a single continent – Pangaea. This could have in part caused the widespread extinctions of marine species at the end of the period by severely reducing shallow coastal areas preferred by many marine organisms. Paleogeography[edit]

Geography of the Permian
Permian world

During the Permian, all the Earth's major landmasses were collected into a single supercontinent known as Pangaea. Pangaea
Pangaea straddled the equator and extended toward the poles, with a corresponding effect on ocean currents in the single great ocean ("Panthalassa", the "universal sea"), and the Paleo-Tethys Ocean, a large ocean that was between Asia and Gondwana. The Cimmeria continent rifted away from Gondwana
Gondwana and drifted north to Laurasia, causing the Paleo-Tethys Ocean to shrink. A new ocean was growing on its southern end, the Tethys Ocean, an ocean that would dominate much of the Mesozoic
Mesozoic era. Large continental landmass interiors experience climates with extreme variations of heat and cold ("continental climate") and monsoon conditions with highly seasonal rainfall patterns. Deserts seem to have been widespread on Pangaea. Such dry conditions favored gymnosperms, plants with seeds enclosed in a protective cover, over plants such as ferns that disperse spores in a wetter environment. The first modern trees (conifers, ginkgos and cycads) appeared in the Permian. Three general areas are especially noted for their extensive Permian deposits – the Ural Mountains
Ural Mountains (where Perm
Perm itself is located), China, and the southwest of North America, including the Texas
Texas red beds. The Permian
Permian Basin in the U.S. states of Texas
Texas and New Mexico
New Mexico is so named because it has one of the thickest deposits of Permian
Permian rocks in the world. Climate[edit]

Selwyn Rock, South Australia, an exhumed glacial pavement of Permian age

The climate in the Permian
Permian was quite varied. At the start of the Permian, the Earth
Earth was still in an ice age, which began in the Carboniferous. Glaciers receded around the mid- Permian
Permian period as the climate gradually warmed, drying the continent's interiors.[14] In the late Permian
Permian period, the drying continued although the temperature cycled between warm and cool cycles.[14] Life[edit]

Hercosestria
Hercosestria cribrosa, a reef-forming productid brachiopod (Middle Permian, Glass Mountains, Texas).

Marine biota[edit] Permian
Permian marine deposits are rich in fossil mollusks, echinoderms, and brachiopods.[15] Fossilized shells of two kinds of invertebrates are widely used to identify Permian
Permian strata and correlate them between sites: fusulinids, a kind of shelled amoeba-like protist that is one of the foraminiferans, and ammonoids, shelled cephalopods that are distant relatives of the modern nautilus. By the close of the Permian, trilobites and a host of other marine groups became extinct. Terrestrial biota[edit] Terrestrial life in the Permian
Permian included diverse plants, fungi, arthropods, and various types of tetrapods. The period saw a massive desert covering the interior of Pangaea. The warm zone spread in the northern hemisphere, where extensive dry desert appeared.[15] The rocks formed at that time were stained red by iron oxides, the result of intense heating by the sun of a surface devoid of vegetation cover. A number of older types of plants and animals died out or became marginal elements. The Permian
Permian began with the Carboniferous
Carboniferous flora still flourishing. About the middle of the Permian
Permian a major transition in vegetation began. The swamp-loving lycopod trees of the Carboniferous, such as Lepidodendron
Lepidodendron and Sigillaria, were progressively replaced in the continental interior by the more advanced seed ferns and early conifers. At the close of the Permian, lycopod and equisete swamps reminiscent of Carboniferous
Carboniferous flora survived only on a series of equatorial islands in the Paleo-Tethys Ocean
Paleo-Tethys Ocean that later would become South China.[16] The Permian
Permian saw the radiation of many important conifer groups, including the ancestors of many present-day families. Rich forests were present in many areas, with a diverse mix of plant groups. The southern continent saw extensive seed fern forests of the Glossopteris flora. Oxygen
Oxygen levels were probably high there. The ginkgos and cycads also appeared during this period. Insects[edit] From the Pennsylvanian subperiod of the Carboniferous
Carboniferous period until well into the Permian, the most successful insects were primitive relatives of cockroaches. Six fast legs, four well-developed folding wings, fairly good eyes, long, well-developed antennae (olfactory), an omnivorous digestive system, a receptacle for storing sperm, a chitin-based exoskeleton that could support and protect, as well as a form of gizzard and efficient mouth parts, gave it formidable advantages over other herbivorous animals. About 90% of insects at the start of the Permian
Permian were cockroach-like insects ("Blattopterans").[17] Primitive forms of dragonflies (Odonata) were the dominant aerial predators and probably dominated terrestrial insect predation as well. True Odonata
Odonata appeared in the Permian,[18][19] and all are effectively semi-aquatic insects (aquatic immature stages, and terrestrial adults), as are all modern odonates. Their prototypes are the oldest winged fossils,[20] dating back to the Devonian, and are different in several respects from the wings of other insects.[21] Fossils
Fossils suggest they may have possessed many modern attributes even by the late Carboniferous, and it is possible that they captured small vertebrates, for at least one species had a wing span of 71 cm (28 in).[22] Several other insect groups appeared or flourished during the Permian, including the Coleoptera
Coleoptera (beetles) and Hemiptera (true bugs). Synapsid
Synapsid and amphibian fauna[edit] Early Permian
Permian terrestrial faunas were dominated by pelycosaurs, diadectids and amphibians,[23][24] the middle Permian
Permian by primitive therapsids such as the dinocephalia, and the late Permian
Permian by more advanced therapsids such as gorgonopsians and dicynodonts. Towards the very end of the Permian
Permian the first archosaurs appeared, a group that would give rise to the crurotarsans and the dinosaurs in the following period. Also appearing at the end of the Permian
Permian were the first cynodonts, which would go on to evolve into mammals during the Triassic. Another group of therapsids, the therocephalians (such as Lycosuchus), arose in the Middle Permian.[25][26] There were no aerial vertebrates (with the exception of gliding reptiles, the avicephalans). The Permian
Permian period saw the development of a fully terrestrial fauna and the appearance of the first large herbivores and carnivores. It was the high tide of the anapsids in the form of the massive Pareiasaurs and host of smaller, generally lizard-like groups. A group of small reptiles, the diapsids, started to abound. These were the ancestors to most modern reptiles and the ruling dinosaurs as well as pterosaurs and crocodiles. The synapsid, early ancestors to mammals, also thrived at this time. Synapsids included some large members such as Dimetrodon. The special adaptations of reptiles enabled them to flourish in the drier climate of the Permian
Permian and they grew to dominate the vertebrates.[23] Permian
Permian amphibians consisted of temnospondyli, lepospondyli and batrachosaurs.

Edaphosaurus pogonias
Edaphosaurus pogonias and Platyhystrix
Platyhystrix – Early Permian, North America and Europe

Dimetrodon
Dimetrodon grandis and Eryops
Eryops – Early Permian, North America

Ocher fauna, Estemmenosuchus uralensis
Estemmenosuchus uralensis and Eotitanosuchus
Eotitanosuchus – Middle Permian, Ural Region

Titanophoneus
Titanophoneus and Ulemosaurus
Ulemosaurus – Ural Region

Inostrancevia
Inostrancevia alexandri and Scutosaurus
Scutosaurus – Late Permian, North European Russia (Northern Dvina)

Permian– Triassic
Triassic extinction event[edit]

The Permian– Triassic
Triassic extinction event, labeled "End P" here, is the most significant extinction event in this plot for marine genera which produce large numbers of fossils.

Main article: Permian– Triassic
Triassic extinction event The Permian
Permian ended with the most extensive extinction event recorded in paleontology: the Permian– Triassic
Triassic extinction event. 90% to 95% of marine species became extinct, as well as 70% of all land organisms. It is also the only known mass extinction of insects.[8][27] Recovery from the Permian- Triassic
Triassic extinction event was protracted; on land, ecosystems took 30 million years to recover.[9] Trilobites, which had thrived since Cambrian
Cambrian times, finally became extinct before the end of the Permian. Nautiluses, a species of cephalopods, surprisingly survived this occurrence. There is evidence that magma, in the form of flood basalt, poured onto the surface in what is now called the Siberian Traps, for thousands of years, contributing to the environmental stress that led to mass extinction. The reduced coastal habitat and highly increased aridity probably also contributed. Based on the amount of lava estimated to have been produced during this period, the worst-case scenario is the release of enough carbon dioxide from the eruptions to raise world temperatures five degrees Celsius.[14] Another hypothesis involves ocean venting of hydrogen sulfide gas. Portions of the deep ocean will periodically lose all of its dissolved oxygen allowing bacteria that live without oxygen to flourish and produce hydrogen sulfide gas. If enough hydrogen sulfide accumulates in an anoxic zone, the gas can rise into the atmosphere. Oxidizing gases in the atmosphere would destroy the toxic gas, but the hydrogen sulfide would soon consume all of the atmospheric gas available. Hydrogen sulfide
Hydrogen sulfide levels might have increased dramatically over a few hundred years. Models of such an event indicate that the gas would destroy ozone in the upper atmosphere allowing ultraviolet radiation to kill off species that had survived the toxic gas.[28] There are species that can metabolize hydrogen sulfide. Another hypothesis builds on the flood basalt eruption theory. An increase in temperature of five degrees Celsius would not be enough to explain the death of 95% of life. But such warming could slowly raise ocean temperatures until frozen methane reservoirs below the ocean floor near coastlines melted, expelling enough methane (among the most potent greenhouse gases) into the atmosphere to raise world temperatures an additional five degrees Celsius. The frozen methane hypothesis helps explain the increase in carbon-12 levels found midway in the Permian– Triassic
Triassic boundary layer. It also helps explain why the first phase of the layer's extinctions was land-based, the second was marine-based (and starting right after the increase in C-12 levels), and the third land-based again.[29] An even more speculative hypothesis is that intense radiation from a nearby supernova was responsible for the extinctions.[30] It has been hypothesised that huge meteorite impact crater (Wilkes Land crater) with a diameter of around 500 kilometers in Antarctica represents an impact event that may be related to the extinction.[31] The crater is located at a depth of 1.6 kilometers beneath the ice of Wilkes Land in eastern Antarctica. The scientists speculate that this impact may have caused the Permian– Triassic
Triassic extinction event, although its age is bracketed only between 100 million and 500 million years ago. They also speculate that it may have contributed in some way to the separation of Australia from the Antarctic landmass, which were both part of a supercontinent called Gondwana. Levels of iridium and quartz fracturing in the Permian- Triassic
Triassic layer do not approach those of the Cretaceous– Paleogene boundary layer. Given that a far greater proportion of species and individual organisms became extinct during the former, doubt is cast on the significance of a meteorite impact in creating the latter. Further doubt has been cast on this theory based on fossils in Greenland that show the extinction to have been gradual, lasting about eighty thousand years, with three distinct phases.[32] Many scientists argue that the Permian– Triassic
Triassic extinction event was caused by a combination of some or all of the hypotheses above and other factors; the formation of Pangaea
Pangaea decreased the number of coastal habitats and may have contributed to the extinction of many clades.[citation needed] See also[edit]

Permian
Permian portal

List of fossil sites
List of fossil sites (with link directory) Olson's Extinction Permian
Permian tetrapods

References[edit]

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