The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the

Carboniferous The Carboniferous ( ) is a geologic period and system of the Paleozoic that spans 60 million years from the end of the Devonian Period million years ago ( Mya), to the beginning of the Permian Period, million years ago. The name ''Carboniferous ...

Period million years ago (Mya), to the beginning of the

Triassic The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period ...

Period 251.9 Mya. It is the last period of the Paleozoic Era; the following Triassic Period belongs to the Mesozoic Era. The concept of the Permian was introduced in 1841 by geologist Sir Roderick Murchison, who named it after the region of Perm in

Russia Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-eight ...

. The Permian witnessed the diversification of the two groups of

amniote Amniotes are a clade of tetrapod vertebrates that comprises sauropsids (including all reptiles and birds, and extinct parareptiles and non-avian dinosaurs) and synapsids (including pelycosaurs and therapsids such as mammals). They are distin ...

s, the synapsids and the sauropsids ( reptiles). The world at the time was dominated by the supercontinent

Pangaea Pangaea or Pangea () was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It assembled from the earlier continental units of Gondwana, Euramerica and Siberia during the Carboniferous approximately 335 million y ...

, which had formed due to the collision of

Euramerica Laurasia () was the more northern of two large landmasses that formed part of the Pangaea supercontinent from around ( Mya), the other being Gondwana. It separated from Gondwana (beginning in the late Triassic period) during the breakup of Pa ...

and Gondwana during the Carboniferous. Pangaea was surrounded by the superocean Panthalassa. The Carboniferous rainforest collapse left behind vast regions of desert within the continental interior. Amniotes, which could better cope with these drier conditions, rose to dominance in place of their amphibian ancestors. Various authors recognise at least three, and possibly four extinction events in the Permian. The end of the Early Permian (

Cisuralian The Cisuralian is the first series/epoch of the Permian. The Cisuralian was preceded by the Pennsylvanian and followed by the Guadalupian. The Cisuralian Epoch is named after the western slopes of the Ural Mountains in Russia and Kazakhstan and ...

) saw a major faunal turnover, with most lineages of primitive "

pelycosaur Pelycosaur ( ) is an older term for basal or primitive Late Paleozoic synapsids, excluding the therapsids and their descendants. Previously, the term ''mammal-like reptile'' had been used, and pelycosaur was considered an order, but this is no ...

" synapsids becoming extinct, being replaced by more advanced

therapsids Therapsida is a major group of eupelycosaurian synapsids that includes mammals, their ancestors and relatives. Many of the traits today seen as unique to mammals had their origin within early therapsids, including limbs that were oriented more ...

. The end of the

Capitanian In the geologic timescale, the Capitanian is an age or stage of the Permian. It is also the uppermost or latest of three subdivisions of the Guadalupian Epoch or Series. The Capitanian lasted between and million years ago. It was preceded by ...

Stage of the Permian was marked by the major

Capitanian mass extinction event The Capitanian mass extinction event, also known as the end-Guadalupian extinction event or the pre-Lopingian crisis was an extinction event that predated the end-Permian extinction event and occurred around 260 million years ago during a period ...

, associated with the eruption of the

Emeishan Traps The Emeishan Traps constitute a flood basalt volcanic province, or large igneous province, in south-western China, centred in Sichuan province. It is sometimes referred to as the Permian Emeishan Large Igneous Province or Emeishan Flood Basalts. Li ...

. The Permian (along with the Paleozoic) ended with the Permian–Triassic extinction event, the largest mass extinction in Earth's history (which is the last of the three or four crises that occurred in the Permian), in which nearly 81% of marine species and 70% of terrestrial species died out, associated with the eruption of the Siberian Traps. It took well into the Triassic for life to recover from this catastrophe; on land, ecosystems took 30 million years to recover.

Etymology and history

Prior to the introduction of the term "Permian", rocks of equivalent age in Germany had been named the

Rotliegend The Rotliegend, Rotliegend Group or Rotliegendes (german: the underlying red) is a lithostratigraphic unit (a sequence of rock strata) of latest Carboniferous to Guadalupian (middle Permian) age that is found in the subsurface of large areas in we ...

and

Zechstein The Zechstein ( German either from ''mine stone'' or ''tough stone'') is a unit of sedimentary rock layers of Middle to Late Permian (Guadalupian to Lopingian) age located in the European Permian Basin which stretches from the east coast of Engla ...

, and in Great Britain as the New Red Sandstone. The term "Permian" was introduced into geology in 1841 by Sir Roderick Impey Murchison, president of the Geological Society of London, after extensive Russian explorations undertaken with

Édouard de Verneuil Philippe Édouard Poulletier de Verneuil (13 February 180529 May 1873) was a French paleontologist.Ural Mountains in the years 1840 and 1841. Murchison identified "vast series of beds of marl, schist, limestone, sandstone and conglomerate” that succeeded

strata in the region. Murchison, in collaboration with Russian geologists, named the period after the surrounding Russian region and the city of Perm, which itself take their name from the medieval kingdom of

Permia Great Perm, or simply Perm, in Latin ''Permia'', was a medieval historical region in what is now the Perm Krai of the Russian Federation. Cherdyn is said to have been its capital. The origin of the name ''Perm'' is uncertain. Most common exp ...

that occupied the same region hundreds of years prior, and which now lies in the

Perm Krai Perm Krai (russian: Пе́рмский край, r=Permsky kray, p=ˈpʲɛrmskʲɪj ˈkraj, ''Permsky krai'', , ''Perem lador'') is a federal subject of Russia (a krai) that came into existence on December 1, 2005 as a result of the 2004 ref ...

of Russia. Between 1853 and 1867,

Jules Marcou Jules Marcou (April 20, 1824 – April 17, 1898) was a French-Swiss-American geologist. Biography He was born at Salins, in the ''département'' of Jura, in France. He was educated at Besançon and at the Collège Saint Louis, Paris. After co ...

recognised Permian strata in a large area of North America from the Mississippi River to the

Colorado River The Colorado River ( es, Río Colorado) is one of the principal rivers (along with the Rio Grande) in the Southwestern United States and northern Mexico. The river drains an expansive, arid watershed that encompasses parts of seven U.S. sta ...

and proposed the name "Dyassic", from "Dyas" and "Trias", though Murchison rejected this in 1871. The Permian system was controversial for over a century after its original naming, with the United States Geological Survey until 1941 considering the Permian a subsystem of the Carboniferous equivalent to the Mississippian and Pennsylvanian.

Geology

The Permian Period is divided into three

epochs In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured. The moment of epoch is usually decided by ...

, from oldest to youngest, the Cisuralian, Guadalupian, and Lopingian. Geologists divide the rocks of the Permian into a

stratigraphic Stratigraphy is a branch of geology concerned with the study of rock layers ( strata) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks. Stratigraphy has three related subfields: lithostra ...

set of smaller units called

stages Stage or stages may refer to: Acting * Stage (theatre), a space for the performance of theatrical productions * Theatre, a branch of the performing arts, often referred to as "the stage" * ''The Stage'', a weekly British theatre newspaper * St ...

, each formed during corresponding time intervals called ages. Stages can be defined globally or regionally. For ''global'' stratigraphic correlation, the International Commission on Stratigraphy (ICS) ratify global stages based on a

Global Boundary Stratotype Section and Point A Global Boundary Stratotype Section and Point (GSSP) is an internationally agreed upon reference point on a stratigraphic section which defines the lower boundary of a stage on the geologic time scale. The effort to define GSSPs is conducted ...

(GSSP) from a single

formation Formation may refer to: Linguistics * Back-formation, the process of creating a new lexeme by removing or affixes * Word formation, the creation of a new word by adding affixes Mathematics and science * Cave formation or speleothem, a secondar ...

stratotype A stratotype or type section in geology is the physical location or outcrop of a particular reference exposure of a stratigraphic sequence or stratigraphic boundary. If the stratigraphic unit is layered, it is called a stratotype, whereas the stan ...

) identifying the lower boundary of the stage. The ages of the Permian, from youngest to oldest, are:Cohen, K.M., Finney, S.C., Gibbard, P.L. & Fan, J.-X. (2013; updated
The ICS International Chronostratigraphic Chart
Episodes 36: 199-204. For most of the 20th century, the Permian was divided into the Early and Late Permian, with the Kungurian being the last stage of the Early Permian. Glenister and colleagues in 1992 proposed a tripartite scheme, advocating that the Roadian-Capitanian was distinct from the rest of the Late Permian, and should be regarded as a separate epoch. The tripartite split was adopted after a formal proposal by Glenister et al. (1999). Historically, most marine biostratigraphy of the Permian was based on

ammonoids Ammonoids are a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs, commonly referred to as ammonites, are more closely related to living coleoids (i.e., octopuses, squid and cuttlefish ...

; however, ammonoid localities are rare in Permian stratigraphic sections, and species characterise relatively long periods of time. All GSSPs for the Permian are based around the

first appearance datum First appearance datum (FAD) is a term used by geologists and paleontologists to designate the first appearance of a species in the geologic record. FADs are determined by identifying the geologically oldest fossil discovered, to date, of a particu ...

of specific species of

conodont Conodonts (Greek ''kōnos'', " cone", + ''odont'', "tooth") are an extinct group of agnathan (jawless) vertebrates resembling eels, classified in the class Conodonta. For many years, they were known only from their tooth-like oral elements, whic ...

, an enigmatic group of jawless

chordate A chordate () is an animal of the phylum Chordata (). All chordates possess, at some point during their larval or adult stages, five synapomorphies, or primary physical characteristics, that distinguish them from all the other taxa. These five ...

s with hard tooth-like oral elements. Conodonts are used as

index fossils Biostratigraphy is the branch of stratigraphy which focuses on correlating and assigning relative ages of rock strata by using the fossil assemblages contained within them.Hine, Robert. “Biostratigraphy.” ''Oxford Reference: Dictionary of Bi ...

for most of the Palaeozoic and the Triassic.

Cisuralian

The Cisuralian Series is named after the strata exposed on the western slopes of the Ural Mountains in Russia and Khazakhstan. The name was proposed by J. B. Waterhouse in 1982 to comprise the Asselian, Sakmarian, and Artinskian stages. The Kungurian was later added to conform to the Russian "Lower Permian".

Albert Auguste Cochon de Lapparent Albert Auguste Cochon de Lapparent (30 December 18395 May 1908) was a French geologist. Life He was born at Bourges. After studying at the École polytechnique from 1858 to 1860 he became ''ingénieur au corps des mines'', and took part in drawi ...

in 1900 had proposed the "Uralian Series", but the subsequent inconsistent usage of this term meant that it was later abandoned. The Asselian was named by the Russian stratigrapher V.E. Ruzhenchev in 1954, after the

Assel River Assel (russian: Ассель; ba, Әселе, ''Äsele'') is a river in Russia, that flows through Bashkortostan and the Orenburg Oblast. The river mouth is 14 km along the left bank of the Bolshoy Ik. The river is 51 km long and the ...

in the southern Ural Mountains. The GSSP for the base of the Asselian is located in the Aidaralash River valley near

Aqtöbe Aktobe ( kz, Ақтөбе, Aqtöbe; russian: Актобе, Aktobe) is a city on the Ilek River in Kazakhstan. It is the administrative center of Aktobe Region. In 2020, it had a population of 500,757 people. Aktobe is located in the west of Ka ...

, Kazakhstan, which was ratified in 1996. The beginning of the stage is defined by the first appearance of '' Streptognathodus postfusus.'' The Sakmarian is named in reference to the Sakmara River in the southern Urals, and was coined by

Alexander Karpinsky Alexander Petrovich Karpinsky (russian: Александр Петрович Карпинский, trl. Aljeksandr Pjetrovič Karpinskij; 7 January 1847 ( NS) – 15 July 1936) was a prominent Russian and Soviet geologist and mineralogist, and ...

in 1874. The GSSP for the base of the Sakmarian is located at the Usolka section in the southern Urals, which was ratified in 2018. The GSSP is defined by the first appearance of '' Sweetognathus binodosus''. The Artinskian was named after the city of Arti in Sverdlovsk Oblast, Russia. It was named by Karpinsky in 1874. The Artinskian currently lacks a defined GSSP. The proposed definition for the base of the Artinskian is the first appearance of ''Sweetognathus aff. S. whitei.'' The Kungurian takes its name after

Kungur Kungur (russian: Кунгу́р) is a town in the southeast of Perm Krai, Russia, located in the Ural Mountains at the confluence of the rivers Iren and Shakva with the Sylva (Kama's basin). Population: 64,800 (1959); 36,000 (1939). His ...

, a city in Perm Krai. The stage was introduced by Alexandr Antonovich Stukenberg in 1890. The Kungurian currently lacks a defined GSSP. Recent proposals have suggested the appearance of ''Neostreptognathodus pnevi'' as the lower boundary.

Guadalupian

The Guadalupian Series is named after the Guadalupe Mountains in Texas and New Mexico, where extensive marine sequences of this age are exposed. It was named by George Herbert Girty in 1902.Glenister, B.F., Wardlaw, B.R. et al. 1999
Proposal of Guadalupian and component Roadian, Wordian and Capitanian stages as international standards for the middle Permian series
''Permophiles'', 34, 3–11. The Roadian was named in 1968 in reference to the Road Canyon Member of the Word Formation in Texas. The GSSP for the base of the Roadian is located 42.7m above the base of the Cutoff Formation in Stratotype Canyon, Guadalupe Mountains, Texas, and was ratified in 2001. The beginning of the stage is defined by the first appearance of ''Jinogondolella nankingensis''. The Wordian was named in reference to the Word Formation by Johan August Udden in 1916, Glenister and Furnish in 1961 was the first publication to use it as a chronostratigraphic term as a substage of the Guadalupian Stage. The GSSP for the base of the Wordian is located in Guadalupe Pass, Texas, within the sediments of the Getaway Limestone Member of the Cherry Canyon Formation, which was ratified in 2001. The base of the Wordian is defined by the first appearance of the conodont ''Jinogondolella aserrata.'' The Capitanian is named after the Capitan Reef in the Guadalupe Mountains of Texas, named by George Burr Richardson in 1904, and first used in a chronostratigraphic sense by Glenister and Furnish in 1961 as a substage of the Guadalupian Stage. The Captianian was ratified as an international stage by the ICS in 2001. The GSSP for the base of the Captianian is located at Nipple Hill in the southeast Guadalupe Mountains of Texas, and was ratified in 2001, the beginning of the stage is defined by the first appearance of ''Jinogondolella postserrata.''

Lopingian

The Lopingian was first introduced by

Amadeus William Grabau Amadeus William Grabau (January 9, 1870 – March 20, 1946) was an American geologist who worked in China. Biography Grabau's grandfather, J.A.A. Grabau, led a group of dissident Lutheran immigrants from Germany to Buffalo, New York. His educa ...

in 1923 as the “Loping Series” after

Leping Leping () is a county-level city in the northeast of Jiangxi province, China. It is under the administration of the prefecture-level city of Jingdezhen. Administrative divisions Leping City has 2 subdistricts, 14 towns and 2 townships. ;2 subdist ...

Jiangxi Jiangxi (; ; formerly romanized as Kiangsi or Chianghsi) is a landlocked province in the east of the People's Republic of China. Its major cities include Nanchang and Jiujiang. Spanning from the banks of the Yangtze river in the north into ...

, China. Originally used as a lithostraphic unit, T.K. Huang in 1932 raised the Lopingian to a series, including all Permian deposits in South China that overlie the Maokou Limestone. In 1995, a vote by the Subcommission on Permian Stratigraphy of the ICS adopted the Lopingian as an international standard chronostratigraphic unit.''; 2006
''The Global Stratotype Section and Point (GSSP) for the boundary between the Capitanian and Wuchiapingian Stage (Permian)''
Episodes 29(4), pp. 253–262'' The Wuchiapinginan and Changhsingian were first introduced in 1962, by J. Z. Sheng as the "Wuchiaping Formation" and "Changhsing Formation" within the Lopingian series. The GSSP for the base of the Wuchiapingian is located at Penglaitan, Guangxi, China and was ratified in 2004. The boundary is defined by the first appearance of ''Clarkina postbitteri postbitteri'''''' The Changhsingian was originally derived from the Changxing Limestone, a geological unit first named by the Grabau in 1923, ultimately deriving from

Changxing County () is a county of the prefecture-level city of Huzhou, in the northwest of Zhejiang province, China. Situated on the southwest shore of Lake Tai, it borders the provinces of Jiangsu to the north and Anhui to the west. It has a total area of a ...

, Zhejiang .The GSSP for the base of the Changhsingian is located 88 cm above the base of the Changxing Limestone in the Meishan D section, Zhejiang, China and was ratified in 2005, the boundary is defined by the first appearance of ''Clarkina wangi.'' The GSSP for the base of the Triassic is located at the base of Bed 27c at the Meishan D section, and was ratified in 2001. The GSSP is defined by the first appearance of the conodont '' Hindeodus parvus''.

Regional stages

The Russian Tatarian Stage includes the Lopingian, Capitanian and part of the Wordian, while the underlying Kazanian includes the rest of the Wordian as well at the Roadian. In North America, the Permian is divided into the Wolfcampian (which includes the Nealian and the Lenoxian stages) corresponding to the Asselian through lower Kungurian; the Leonardian (Hessian and Cathedralian stages) corresponding to the upper Kungurian; the Guadalupian; and the Ochoan, corresponding to the Lopingian.

Paleogeography

During the Permian, all the Earth's major landmasses were collected into a single supercontinent known as

, with the microcontinental terranes of Cathaysia to the east. 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 The Paleo-Tethys or Palaeo-Tethys Ocean was an ocean located along the northern margin of the paleocontinent Gondwana that started to open during the Middle Cambrian, grew throughout the Paleozoic, and finally closed during the Late Triassic; exi ...

, a large ocean that existed between Asia and Gondwana. The Cimmeria continent

rift In geology, a rift is a linear zone where the lithosphere is being pulled apart and is an example of extensional tectonics. Typical rift features are a central linear downfaulted depression, called a graben, or more commonly a half-graben wi ...

ed away from Gondwana and drifted north to

Laurasia Laurasia () was the more northern of two large landmasses that formed part of the Pangaea supercontinent from around ( Mya), the other being Gondwana. It separated from Gondwana (beginning in the late Triassic period) during the breakup of Pan ...

, causing the Paleo-Tethys Ocean to shrink. A new ocean was growing on its southern end, the Neotethys Ocean, an ocean that would dominate much of the Mesozoic Era. The

Central Pangean Mountains The Central Pangean Mountains were an extensive northeast–southwest trending mountain range in the central portion of the supercontinent Pangaea during the Carboniferous, Permian and Triassic periods. They were formed as a result of collision be ...

, which began forming due to the collision of Laurasia and Gondwana during the Carboniferous, reached their maximum height during the early Permian around 295 million years ago, comparable to the present Himalayas, but became heavily eroded as the Permian progressed. The

Kazakhstania Kazakhstania ( kk, Qazaqstaniya), the Kazakh terranes, or the Kazakhstan Block, is a geological region in Central Asia which consists of the area roughly centered on Lake Balkhash, north and east of the Aral Sea, south of the Siberian craton and ...

block collided with Baltica during the Cisuralian, while the North China Craton, the

South China Block The Yangtze Plate, also called the South China Block or the South China Subplate, comprises the bulk of southern China. It is separated on the east from the Okinawa Plate by a rift that forms the Okinawa Trough which is a back-arc basin, on the so ...

and Indochina fused to each other and Pangea by the end of the Permian. 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

spore In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, ...

s in a wetter environment. The first modern trees (

conifers Conifers are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single extant class, Pinopsida. All exta ...

, ginkgos and

cycad Cycads are seed plants that typically have a stout and woody ( ligneous) trunk with a crown of large, hard, stiff, evergreen and (usually) pinnate leaves. The species are dioecious, that is, individual plants of a species are either male or ...

s) appeared in the Permian. Three general areas are especially noted for their extensive Permian deposits—the Ural Mountains (where Perm itself is located), China, and the southwest of North America, including the Texas red beds. The Permian Basin in the

U.S. state In the United States, a state is a constituent political entity, of which there are 50. Bound together in a political union, each state holds governmental jurisdiction over a separate and defined geographic territory where it shares its sov ...

s of Texas and New Mexico is so named because it has one of the thickest deposits of Permian rocks in the world.

Paleoceanography

Sea levels dropped slightly during the earliest Permian (Asselian). The sea level was stable at several tens of metres above present during the Early Permian, but there was a sharp drop beginning during the Roadian, culminating in the lowest sea level of the entire Palaeozoic at around present sea level during the Wuchiapingian, followed by a slight rise during the Changhsingian.

Climate

At the start of the Permian, the Earth was still in the

Late Paleozoic icehouse The late Paleozoic icehouse, also known as the Late Paleozoic Ice Age (LPIA) and formerly known as the Karoo ice age, was an ice age that began in the Late Devonian and ended in the Late Permian, occurring from 360 to 255 million years ago (Mya), ...

, which began in the latest Devonian. At the beginning of the Pennsylvanian around 323 million years ago, glaciers began to form around the South Pole, which would grow to cover a vast area. This area extended from the southern reaches of the

Amazon basin The Amazon basin is the part of South America drained by the Amazon River and its tributaries. The Amazon drainage basin covers an area of about , or about 35.5 percent of the South American continent. It is located in the countries of Boliv ...

and covered large areas of southern Africa, as well as most of Australia and Antarctica.

Cyclothems In geology, cyclothems are alternating stratigraphic sequences of marine and non-marine sediments, sometimes interbedded with coal seams. Historically, the term was defined by the European coal geologists who worked in coal basins formed during ...

indicate that the size of the glaciers were controlled by Milankovitch cycles akin to recent ice ages, with

glacial period A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate betw ...

s and

interglacial An interglacial period (or alternatively interglacial, interglaciation) is a geological interval of warmer global average temperature lasting thousands of years that separates consecutive glacial periods within an ice age. The current Holocene i ...

s. The oldest cyclotherms are around 313 million years old while the youngest are around 293 million years old, corresponding to the coldest part of the Late Paleozoic icehouse. Deep ocean temperatures during this time were cold due to the influx of cold bottom waters generated by seasonal melting of the ice cap. By 287 million years ago, temperatures warmed and the South Pole ice cap retreated in what was known as the Artinskian Warming Event (AWE), though glaciers would remain present in the upland regions of eastern Australia, the Transantarctic Mountains, and the mountainous regions of far northern Siberia until the end of the Permian. The Permian was cool in comparison to most other geologic time periods, with modest Pole to Equator temperature gradients. This was interrupted by the Emeishan Thermal Excursion in the late part of the Capitanian, around 260 million years ago, corresponding to the eruption of the

. The end of the Permian is marked by the much larger temperature excursion at the Permian-Triassic boundary, corresponding to the eruption of the Siberian Traps, which released more than 5 teratonnes of CO₂ , more than doubling atmospheric carbon dioxide concentrations.Alt URL
/ref> In addition to becoming warmer, the climate became notably more arid at the end of the Carboniferous and beginning of the Permian, with a significant trend of increasing aridification being observed over the course of the Cisuralian, particularly during the AWE.

Life

Marine invertebrates

Permian marine deposits are rich in fossil mollusks, echinoderms, and

brachiopod Brachiopods (), phylum Brachiopoda, are a phylum of trochozoan animals that have hard "valves" (shells) on the upper and lower surfaces, unlike the left and right arrangement in bivalve molluscs. Brachiopod valves are hinged at the rear end, wh ...

s. Brachiopods were highly diverse during the Permian. The extinct order Productida was the predominant group of Permian brachiopods, accounting for up to about half of all Permian brachiopod genera. Conodonts experienced their lowest diversity of their entire evolutionary history during the Permian. Amongst

, Goniatitida were a major group during the Early-Mid Permian, but declined during the Late Permian. Members of the order

Prolecanitida Prolecanitida is an order of extinct ammonoid cephalopods with discoidal to thinly lenticular shells with goniatitic or ceratitic sutures and which retained the simple retrochoanitic siphuncle with backward extending septal necks. As typical for ...

were less diverse. The Ceratitida originated from the family

Daraelitidae The Daraelitidae form a family in the ammonoid order Prolecanitida from the Upper Mississippian - Middle Permian characterized by discoidal shells with no prominent sculpture, moderately large umbilicus, and goniatitic or ceratitic sutures with a ...

within Prolecanitida during the mid-Permian, and extensively diversified during the Late Permian. Only three families of trilobite are known from the Permian,

Proetidae Proetidae is a family of proetid trilobites. The first species appeared in the Upper Ordovician, and the last genera survived until the Middle Permian. However, if the closely related family Phillipsiidae is actually a subfamily of Proetidae, ...

, Brachymetopidae and

Phillipsiidae Phillipsiidae is a family of proetid trilobites, the various genera of which comprise some of the last of the trilobites, with a range that extended from the Kinderhookian epoch of the Lower Mississippian, to the end of Changhsingian age at Pe ...

. Diversity, origination and extinction rates during the Early Permian were low. Trilobites underwent a diversification during the Kungurian-Wordian, the last in their evolutionary history, before declining during the Late Permian. By the Changhsingian, only a handful (4-6) genera remained.

Terrestrial biota

Terrestrial life in the Permian included diverse plants, fungi,

arthropod Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and cuticle made of chitin, o ...

s, and various types of tetrapods. The period saw a massive desert covering the interior of

. The warm zone spread in the northern hemisphere, where extensive dry desert appeared. 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 began with the Carboniferous flora still flourishing. About the middle of the Permian a major transition in vegetation began. The swamp-loving

lycopod Lycopodiopsida is a class of vascular plants known as lycopods, lycophytes or other terms including the component lyco-. Members of the class are also called clubmosses, firmosses, spikemosses and quillworts. They have dichotomously branching s ...

trees of the Carboniferous, such as ''

Lepidodendron ''Lepidodendron'' is an extinct genus of primitive vascular plants belonging to the family Lepidodendraceae, part of a group of Lycopodiopsida known as scale trees or arborescent lycophytes, related to quillworts and lycopsids (club mosses). Th ...

'' and ''

Sigillaria ''Sigillaria'' is a genus of extinct, spore-bearing, arborescent (tree-like) plants. It was a lycopodiophyte, and is related to the lycopsids, or club-mosses, but even more closely to quillworts, as was its associate ''Lepidodendron''. Fossil ...

'', were progressively replaced in the continental interior by the more advanced seed ferns and early

as a result of the Carboniferous rainforest collapse. At the close of the Permian, lycopod and equisete swamps reminiscent of Carboniferous flora survived only on a series of equatorial islands in the

that later would become

South China South China () is a geographical and cultural region that covers the southernmost part of China. Its precise meaning varies with context. A notable feature of South China in comparison to the rest of China is that most of its citizens are not n ...

. The 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 ''Glossopteris'' tymology: from Ancient Greek γλῶσσα (glôssa, " tongue ") + πτερίς (pterís, " fern ")is the largest and best-known genus of the extinct Permian order of seed ferns known as Glossopteridales (also known as Arberia ...

'' flora. Oxygen levels were probably high there. The

ginkgos ''Ginkgo'' is a genus of non-flowering seed plants. The scientific name is also used as the English name. The order to which it belongs, Ginkgoales, first appeared in the Permian, 270 million years ago, and is now the only living genus within t ...

and

s also appeared during this period.

Insects

Permocupes sojanensis holotype and reconstruction

Insects, which had first appeared and become abundant during the preceding Carboniferous, experienced a dramatic increase in diversification during the Early Permian. Towards the end of the Permian, there was a substantial drop in both origination and extinction rates. The dominant insects during the Permian Period were early representatives of

Paleoptera The name Palaeoptera (from Greek ( 'old') + ( 'wing')) has been traditionally applied to those ancestral groups of winged insects (most of them extinct) that lacked the ability to fold the wings back over the abdomen as characterizes the Neopt ...

Polyneoptera The cohort Polyneoptera is a proposed taxonomic ranking for the Orthoptera (grasshoppers, crickets, etc.) and all other Neopteran insects believed to be more closely related to Orthoptera than to any other insect orders. These winged insects, n ...

, and

Paraneoptera Paraneoptera or Acercaria is a superorder of insects which includes lice ( bark lice and true lice), thrips, and hemipterans, the true bugs. It also includes the extinct order Permopsocida, known from fossils dating from the Early Permian to t ...

Palaeodictyopteroidea The Palaeodictyopteroidea or Paleodictyopterida are an extinct superorder of Palaeozoic beaked insects, characterised by unique mouthparts consisting of 5 stylets. They represent the first important terrestrial herbivores, and the first major gr ...

, which had represented the dominant group of insects during the Carboniferous, declined during the Permian. This is likely due to competition by

Hemiptera Hemiptera (; ) is an order of insects, commonly called true bugs, comprising over 80,000 species within groups such as the cicadas, aphids, planthoppers, leafhoppers, assassin bugs, bed bugs, and shield bugs. They range in size from to aroun ...

, due to their similar mouthparts and therefore ecology. Primitive relatives of damselflies and dragonflies (

Meganisoptera Meganisoptera is an extinct order of very large to gigantic insects, informally called griffinflies. The order was formerly named Protodonata, the "proto-Odonata", for their similar appearance and supposed relation to modern Odonata (damselflies ...

), which include the largest flying insects of all time, also declined during the Permian.

Holometabola Endopterygota (from Ancient Greek ''endon'' 'inner' + ''pterón'' 'wing' + New Latin ''-ota'' 'having'), also known as Holometabola, is a superorder of insects within the infraclass Neoptera that go through distinctive larval, pupal, and adult s ...

, the largest group of modern insects, also diversified during this time. The earliest known

beetle Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 describ ...

s, appear at the beginning of the Permian. Early beetles such as members of

Permocupedidae Permocupedidae is a family of Protocoleopteran stem group beetles. They first appeared during the Early Permian, and were one of the dominant groups of beetles during the Middle Permian. They became rare in the Late Permian, with only one species ...

likely

xylophagous Xylophagy is a term used in ecology to describe the habits of an herbivorous animal whose diet consists primarily (often solely) of wood. The word derives from Greek ''ξυλοφάγος'' (''xulophagos'') "eating wood", from ''ξύλον'' (') ...

feeding on decaying wood. Several lineages, such as Schizophoridae expanded into aquatic habitats by the Late Permian. Members of the modern orders

Archostemata The Archostemata are the smallest suborder of beetles, consisting 45 living species in five families. They are an ancient lineage with a number of primitive characteristics. Antennae may be thread-shaped (filiform) or like a string of beads (mon ...

and

Adephaga The Adephaga (from Greek ἀδηφάγος, ''adephagos'', "gluttonous") are a suborder of beetles, and with more than 40,000 recorded species in 10 families, the second-largest of the four beetle suborders. Members of this suborder are collecti ...

are known from the Late Permian. Complex wood boring traces found in the Late Permian of China suggest that members of

Polyphaga Polyphaga is the largest and most diverse suborder of beetles. It comprises 144 families in 16 superfamilies, and displays an enormous variety of specialization and adaptation, with over 350,000 described species, or approximately 90% of the be ...

, the most diverse group of modern beetles, were also present in the Permian.

Tetrapods

The terrestrial fossil record of the Permian is patchy and temporally discontinuous. Early Permian records are dominated by equatorial Europe and North America, while those of the Middle and Late Permian are dominated by temperate Karoo Supergroup sediments of South Africa and the Ural region of European Russia. Early Permian terrestrial faunas of North America and Europe were dominated by primitive

synapsids including the herbivorous edaphosaurids, and carnivorous sphenacodontids,

diadectids Diadectidae is an extinct family of early tetrapods that lived in what is now North America and Europe during the Late Carboniferous and Early Permian in Asia during the Late Permian. They were the first herbivorous tetrapods, and also the first ...

and

amphibian Amphibians are four-limbed and ectothermic vertebrates of the class Amphibia. All living amphibians belong to the group Lissamphibia. They inhabit a wide variety of habitats, with most species living within terrestrial, fossorial, arborea ...

s.Huttenlocker, A. K., and E. Rega. 2012. The Paleobiology and Bone Microstructure of Pelycosaurian-grade Synapsids. Pp. 90–119 in A. Chinsamy (ed.) Forerunners of Mammals: Radiation, Histology, Biology. Indiana University Press.

Amniotes

A faunal turnover occurred at the transition between the Cisuralian and Guadalupian, with the decline of amphibians and the replacement of pelycosaurs with more advanced therapsids. If terrestrial deposition ended around the end of the Cisuralian in North America and began in Russia during the early Guadalupian, a continuous record of the transition is not preserved. Uncertain dating has led to suggestions that there is a global hiatus in the terrestrial fossil record during the late Kungurian and early Roadian, referred to as "Olson's Gap" that obscures the nature of the transition. Other proposals have suggested that the North American and Russian records overlap, with the latest terrestrial North American deposition occurring during the Roadian, suggesting that there was an extinction event, dubbed " Olson's Extinction". The Middle Permian faunas of South Africa and Russia are dominated by therapsids, most abundantly by the diverse Dinocephalia. Dinocephalians become extinct at the end of the Middle Permian, during the

. Late Permian faunas are dominated by advanced therapsids such as the predatory sabertoothed gorgonopsians and herbivorous beaked

dicynodont Dicynodontia is an extinct clade of anomodonts, an extinct type of non-mammalian therapsid. Dicynodonts were herbivorous animals with a pair of tusks, hence their name, which means 'two dog tooth'. Members of the group possessed a horny, typic ...

s, alongside large herbivorous

pareiasaur Pareiasaurs (meaning "cheek lizards") are an extinct clade of large, herbivorous parareptiles. Members of the group were armoured with scutes which covered large areas of the body. They first appeared in southern Pangea during the Middle Permian ...

parareptiles Parareptilia ("at the side of reptiles") is a subclass or clade of basal sauropsids (reptiles), typically considered the sister taxon to Eureptilia (the group that likely contains all living reptiles and birds). Parareptiles first arose near the ...

. The

Archosauromorpha Archosauromorpha (Greek for "ruling lizard forms") is a clade of diapsid reptiles containing all reptiles more closely related to archosaurs (such as crocodilians and dinosaurs, including birds) rather than lepidosaurs (such as tuataras, lizard ...

, the group of reptiles that would give rise to the

pseudosuchia Pseudosuchia is one of two major divisions of Archosauria, including living crocodilians and all archosaurs more closely related to crocodilians than to birds. Pseudosuchians are also informally known as "crocodilian-line archosaurs". Prior to ...

ns, dinosaurs, and

pterosaur Pterosaurs (; from Greek ''pteron'' and ''sauros'', meaning "wing lizard") is an extinct clade of flying reptiles in the order, Pterosauria. They existed during most of the Mesozoic: from the Late Triassic to the end of the Cretaceous (228 to ...

s in the following Triassic, first appeared and diversified during the Late Permian, including the first appearance of the

Archosauriformes Archosauriformes (Greek for 'ruling lizards', and Latin for 'form') is a clade of diapsid reptiles that developed from archosauromorph ancestors some time in the Latest Permian (roughly 252 million years ago). It was defined by Jacques Gauthie ...

during the latest Permian.

Cynodont The cynodonts () ( clade Cynodontia) are a clade of eutheriodont therapsids that first appeared in the Late Permian (approximately 260 mya), and extensively diversified after the Permian–Triassic extinction event. Cynodonts had a wide variet ...

s, the group of therapsids ancestral to modern mammals, first appeared and gained a worldwide distribution during the Late Permian. Another group of therapsids, the

therocephalia Therocephalia is an extinct suborder of eutheriodont therapsids (mammals and their close relatives) from the Permian and Triassic. The therocephalians ("beast-heads") are named after their large skulls, which, along with the structure of thei ...

ns (such as ''

Lycosuchus ''Lycosuchus'' ("wolf crocodile") is an extinct genus of carnivorous therocephalians which lived in the Middle Permian 265—260 Ma existing for approximately . As a member of the Lycosuchidae, the genus represents one of the earliest diverging ...

''), arose in the Middle Permian. There were no flying vertebrates, though the extinct lizard like reptile family

Weigeltisauridae Weigeltisauridae is a family of gliding neodiapsid reptiles that lived during the Late Permian, between 258 and 252 million years ago. Fossils of weigeltisaurids have been found in Madagascar, Germany, Great Britain, and Russia. A possible weigel ...

from the Late Permian had extendable wings like modern gliding lizards, and are the oldest known gliding vertebrates. Synapsids (the group that would later include mammals) thrived and diversified greatly at this time. Permian synapsids included some large members such as '' Dimetrodon''. The special adaptations of synapsids enabled them to flourish in the drier climate of the Permian and they grew to dominate the vertebrates.

Amphibians

Permian stem-amniotes consisted of

temnospondyli Temnospondyli (from Greek τέμνειν, ''temnein'' 'to cut' and σπόνδυλος, ''spondylos'' 'vertebra') is a diverse order of small to giant tetrapods—often considered primitive amphibians—that flourished worldwide during the Carb ...

lepospondyli Lepospondyli is a diverse taxon of early tetrapods. With the exception of one late-surviving lepospondyl from the Late Permian of Morocco ('' Diplocaulus minumus''), lepospondyls lived from the Early Carboniferous ( Mississippian) to the Early ...

and batrachosaurs. Temnospondyls reached a peak of diversity in the Cisuralian, with a substantial decline during the Guadalupian-Lopingian following Olson's extinction, with the family diversity dropping below Carboniferous levels.

Embolomeres Embolomeri is an order of tetrapods or stem-tetrapods, possibly members of Reptiliomorpha. Embolomeres first evolved in the Early Carboniferous ( Mississippian) Period and were the largest and most successful predatory tetrapods of the Late Carbon ...

, a group of aquatic crocodile-like reptilliomorphs that previously had its last records in the Cisuralian, are now known to have persisted into the Lopingian in China. Modern amphibians (

lissamphibia The Lissamphibia is a group of tetrapods that includes all modern amphibians. Lissamphibians consist of three living groups: the Salientia (frogs, toads, and their extinct relatives), the Caudata (salamanders, newts, and their extinct relatives), ...

ns) are suggested to have originated during Permian, descending from a lineage of

dissorophoid Dissorophoideans are a clade of medium-sized, temnospondyl amphibians that appeared during the Moscovian in Euramerica, and continued through to the Late Permian and the Early Triassic of Gondwana. They are distinguished by various details of t ...

temnospondyls. File:EdaphosaurusDB.jpg, ''

Edaphosaurus pogonias ''Edaphosaurus'' (, meaning "pavement lizard" for dense clusters of teeth) is a genus of extinct edaphosaurid synapsids that lived in what is now North America and Europe around 303.4 to 272.5 million years ago, during the Late Carboniferous to ...

'' and ''

Platyhystrix ''Platyhystrix'' (from el, πλατύς , 'flat' and el, ῠ̔́στρῐξ , 'porcupine') was a temnospondyl amphibian with a distinctive sail along its back, similar to the unrelated synapsids, ''Dimetrodon'' and '' Edaphosaurus''. It lived d ...

'' – Early Permian, North America and Europe File:Dimetr eryopsDB.jpg, '' Dimetrodon grandis'' and ''

Eryops ''Eryops'' (; from Greek , , 'drawn-out' + , , 'face', because most of its skull was in front of its eyes) is a genus of extinct, amphibious temnospondyls. It contains the single species , the fossils of which are found mainly in early Permian ...

'' – Early Permian, North America File:Ocher fauna DB.jpg, Ocher fauna, ''

Estemmenosuchus uralensis ''Estemmenosuchus'' (meaning "crowned crocodile" in Greek) is an extinct genus of large, early omnivorous therapsid. It is believed and interpreted to have lived during the middle part of the Middle Permian around 267 million years ago. The two s ...

'' and ''

Eotitanosuchus ''Eotitanosuchus'' ("dawn giant crocodile") is an extinct genus of biarmosuchian therapsids whose fossils were found in the town of Ochyor in Perm Krai, Russia. It lived about 267 million years ago. The only species is ''Eotitanosuchus olson ...

'' – Middle Permian, Ural Region File:Titanophoneus 3.jpg, ''

Titanophoneus ''Titanophoneus'' ("titanic murderer") is an extinct genus of carnivorous dinocephalian therapsid from the Middle Permian. It is classified within the family Anteosauridae. The type species is ''Titanophoneus potens''. Remains of ''Titanophoneus'' ...

'' and ''

Ulemosaurus ''Ulemosaurus'' is an extinct genus of dinocephalian therapsids that lived 265 to 260 million years ago, at Isheevo in Russian Tatarstan. It was a tapinocephalid, a group of bulky herbivores which flourished in the Middle Permian. ''Ulemosaurus ...

'' – Ural Region File:Inostrancevia 4DB.jpg, '' Inostrancevia alexandri'' and ''

Scutosaurus ''Scutosaurus'' ("shield lizard") is an extinct genus of pareiasaur parareptiles. Its genus name refers to large plates of armor scattered across its body. It was a large anapsid reptile that, unlike most reptiles, held its legs underneath its ...

'' – Late Permian, North European Russia (Northern Dvina)

Fish

The diversity of fish during the Permian is relatively low compared to the following Triassic. The dominant group of

bony fishes Osteichthyes (), popularly referred to as the bony fish, is a diverse superclass of fish that have skeletons primarily composed of bone tissue. They can be contrasted with the Chondrichthyes, which have skeletons primarily composed of cartilage ...

during the Permian were the "Paleopterygii" a paraphyletic grouping of

Actinopterygii Actinopterygii (; ), members of which are known as ray-finned fishes, is a class of bony fish. They comprise over 50% of living vertebrate species. The ray-finned fishes are so called because their fins are webs of skin supported by bony or ho ...

that lie outside of Neopterygii. The earliest unequivocal members of Neopterygii appear during the Early Triassic, but a Permian origin is suspected. The diversity of

coelacanth The coelacanths ( ) are fish belonging to the order Actinistia that includes two extant species in the genus ''Latimeria'': the West Indian Ocean coelacanth (''Latimeria chalumnae''), primarily found near the Comoro Islands off the east coast ...

s is relatively low throughout the Permian in comparison to other marine fishes, though there is an increase in diversity during the terminal Permian (Changhsingian), corresponding with the highest diversity in their evolutionary history during the Early Triassic. Diversity of freshwater fish faunas was generally low and dominated by lungfish and "Paleopterygians". The last common ancestor of all living lungfish is thought to have existed during the Early Permian. Though the fossil record is fragmentary, lungfish appear to have undergone an evolutionary diversification and size increase in freshwater habitats during the Early Permian, but subsequently declined during the middle and late Permian. Permian chondrichthyan faunas are poorly known. Members of the chondrichthyan clade Holocephali, which contains living

chimaera Chimaeras are cartilaginous fish in the order Chimaeriformes , known informally as ghost sharks, rat fish, spookfish, or rabbit fish; the last three names are not to be confused with rattails, Opisthoproctidae, or Siganidae, respectively. A ...

s, reached their apex of diversity during the Carboniferous-Permian, the most famous Permian representative being the "buzz-saw shark" ''

Helicoprion ''Helicoprion'' is an extinct genus of shark-like eugeneodont fish. Almost all fossil specimens are of spirally arranged clusters of the individuals' teeth, called "tooth whorls", which in life were embedded in the lower jaw. As with most extin ...

,'' known for its unusual spiral shaped spiral tooth whorl in the lower jaw.

Hybodonts Hybodontiformes, commonly called hybodonts, are an extinct group of shark-like chondrichthyans, which existed from the late Devonian to the Late Cretaceous. They form the group of Elasmobranchii closest to neoselachians, the clade of modern sha ...

, a group of shark-like chondrichtyans, were widespread and abundant members of marine and freshwater faunas throughout the Permian. Xenacanthiformes, another extinct group of shark-like chondrichtyans, were common in freshwater habitats, and represented the apex predators of freshwater ecosystems.

Flora

The World of the Carboniferous-Permian boundary

Four

floristic provinces A phytochorion, in phytogeography, is a geographic area with a relatively uniform composition of plant species. Adjacent phytochoria do not usually have a sharp boundary, but rather a soft one, a transitional area in which many species from both re ...

in the Permian are recognised, the Angaran, Euramerican, Gondwanan, and Cathaysian realms. The Carboniferous Rainforest Collapse would result in the replacement of

lycopsid Lycopodiopsida is a class of vascular plants known as lycopods, lycophytes or other terms including the component lyco-. Members of the class are also called clubmosses, firmosses, spikemosses and quillworts. They have dichotomously branching s ...

-dominated forests with

tree-fern The tree ferns are arborescent (tree-like) ferns that grow with a trunk elevating the fronds above ground level, making them trees. Many extant tree ferns are members of the order Cyatheales, to which belong the families Cyatheaceae (scaly tre ...

dominated ones during the late Carboniferous in Euramerica, and result in the differentiation of the Cathaysian floras from those of Euramerica. The Gondwanan floristic region was dominated by

Glossopteridales Glossopteridales is an extinct order of plants belonging to Pteridospermatophyta, or seed ferns, also known as Arberiales and Ottokariales. They arose at the beginning of the Permian () on the southern continent of Gondwana, but became extinct a ...

, a group of woody gymnosperm plants, for most of the Permian, extending to high southern latitudes. The ecology of the most prominent glossopterid, ''

'', has been compared to that of

bald cypress ''Taxodium distichum'' (bald cypress, swamp cypress; french: cyprès chauve; ''cipre'' in Louisiana) is a deciduous conifer in the family Cupressaceae. It is native to the southeastern United States. Hardy and tough, this tree adapts to a wide ...

, living in mires with waterlogged soils. The tree-like calamites, distant relatives of modern horsetails, lived in coal swamps and grew in

bamboo Bamboos are a diverse group of evergreen perennial flowering plants making up the subfamily Bambusoideae of the grass family Poaceae. Giant bamboos are the largest members of the grass family. The origin of the word "bamboo" is uncertain, but ...

-like vertical thickets. A mostly complete specimen of ''

Arthropitys ''Arthropitys'' is an extinct genus of calamitacean equisetale. The petrified fossils of ''Arthropitys bistriata'', the type species, can be found at Chemnitz petrified forest, Chemnitz, Germany. History Petrified trunks of tree ferns, seed ...

'' from the Early Permian

Chemnitz petrified forest The Chemnitz petrified forest is a petrified forest in Chemnitz, Germany. Most of the trunks are exhibited in the Museum of Natural History in Chemnitz inside of Kulturkaufhaus Tietz , including slices of trunks with polished edges. A small col ...

of Germany demonstrates that they had complex branching patterns similar to modern angiosperm trees. Diorama of a Permian forest floor - Eryops (45651934102)

Diorama of a Permian forest floor - Eryops (45651934102)

The oldest likely record of

Ginkgoales Ginkgoales are a gymnosperm order containing only one extant species: '' Ginkgo biloba'', the ginkgo tree. It is monotypic, (the only taxon) within the class Ginkgoopsida, which itself is monotypic within the division Ginkgophyta . The order inc ...

(the group containing '' Ginkgo'' and its close relatives) is '' Trichopitys heteromorpha'' from the earliest Permian of France. The oldest known fossils definitively assignable to modern

s are known from the Late Permian. In Cathaysia, where a wet tropical frost free climate prevailed, the

Noeggerathiales Noeggerathiales is a now-extinct order of vascular plants. The fossil range of the order extends from the Upper Carboniferous to the upper Permian (Lopingian). Due to gaps in the fossil record, the group is incompletely known and poorly defined, ...

, an extinct group of tree fern-like

progymnosperm The progymnosperms are an extinct group of woody, spore-bearing plants that is presumed to have evolved from the trimerophytes, and eventually gave rise to the gymnosperms, ancestral to acrogymnosperms and angiosperms (flowering plants). They h ...

s were a common component of the flora The earliest Permian (~ 298 million years ago) Cathyasian Wuda Tuff flora, representing a coal swamp community, has an upper canopy consisting of

tree ''

,'' with a lower canopy consisting of Marattialean tree ferns, and Noeggerathiales. Early conifers appeared in the Late Carboniferous, represented by primitive

walchia ''Walchia'' is a fossil conifer, cypress-like genus found in upper Pennsylvanian (Carboniferous) and lower Permian (about 310-290 Mya) rocks of Europe and North America. A forest of in-situ Walchia tree-stumps is located on the Northumberland ...

n conifers, but were replaced with more derived voltzialeans during the Permian. Permian conifers were very similar morphologically to their modern counterparts, and were adapted to stressed dry or seasonally dry climatic conditions.

Bennettitales Bennettitales (also known as cycadeoids) is an extinct order of seed plants that first appeared in the Permian period and became extinct in most areas toward the end of the Cretaceous. Bennettitales are among the most common Mesozoic seed plants ...

, which would go on to become in widespread the Mesozoic, first appeared during the Cisuralian in China. Lyginopterids, which had declined in the late Pennsylvanian and subsequently have a patchy fossil record, survived into the Late Permian in Cathaysia and equatorial east Gondwana.

Permian–Triassic extinction event

The Permian ended with the most extensive extinction event recorded in paleontology: the Permian–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. Recovery from the Permian–Triassic extinction event was protracted; on land, ecosystems took 30 million years to recover. Trilobites, which had thrived since

Cambrian The Cambrian Period ( ; sometimes symbolized Ꞓ) was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million years ago ( ...

times, finally became extinct before the end of the Permian.

Nautiloids Nautiloids are a group of marine cephalopods (Mollusca) which originated in the Late Cambrian and are represented today by the living ''Nautilus'' and ''Allonautilus''. Fossil nautiloids are diverse and speciose, with over 2,500 recorded species. ...

, a subclass of cephalopods, surprisingly survived this occurrence. There is evidence that magma, in the form of flood basalt, poured onto the Earth's 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.Palaeos: Life Through Deep Time > The Permian Period
Accessed 1 April 2013. 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 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. 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 gas A greenhouse gas (GHG or GhG) is a gas that absorbs and emits radiant energy within the thermal infrared range, causing the greenhouse effect. The primary greenhouse gases in Earth's atmosphere are water vapor (), carbon dioxide (), methane ...

es) 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 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.

References

External links

University of California offers a more modern Permian stratigraphy

* * ttp://www.geo-lieven.com/erdzeitalter/perm/perm.htm Examples of Permian Fossils
Permian (chronostratigraphy scale)
* {{Authority control Geological periods

Etymology and history

Geology

Cisuralian

Guadalupian

Lopingian

Regional stages

Paleogeography

Paleoceanography

Climate

Life

Marine invertebrates

Terrestrial biota

Insects

Tetrapods

Amniotes

Amphibians

Fish

Flora

Permian–Triassic extinction event

See also

References

Further reading

External links