The Cisuralian is the first series/

epoch 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 ...

of the

Permian The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleo ...

. The Cisuralian was preceded by the Pennsylvanian and followed by the

Guadalupian The Guadalupian is the second and middle series/ epoch of the Permian. The Guadalupian was preceded by the Cisuralian and followed by the Lopingian. It is named after the Guadalupe Mountains of New Mexico and Texas, and dates between 272.95 � ...

. The Cisuralian Epoch is named after the western slopes of the

Ural Mountains The Ural Mountains ( ; rus, Ура́льские го́ры, r=Uralskiye gory, p=ʊˈralʲskʲɪjə ˈɡorɨ; ba, Урал тауҙары) or simply the Urals, are a mountain range that runs approximately from north to south through western ...

in Russia and

Kazakhstan Kazakhstan, officially the Republic of Kazakhstan, is a transcontinental country located mainly in Central Asia and partly in Eastern Europe. It borders Russia to the north and west, China to the east, Kyrgyzstan to the southeast, Uzbeki ...

and dates between 298.9 ± 0.15 – 272.3 ± 0.5 Mya. The Cisuralian is often synonymous with the informal terms early Permian or lower Permian. It corresponds approximately with the Wolfcampian in southwestern North America. The series saw the appearance of

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 and

flies Flies are insects of the order Diptera, the name being derived from the Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advanced m ...

and was a relatively stable warming period of about 21 million years.

Name and background

The Cisuralian is the first series or epoch of the Permian. The Cisuralian was preceded by the last Pennsylvanian epoch (

Gzhelian The Gzhelian ( ) is an age in the ICS geologic timescale or a stage in the stratigraphic column. It is the youngest stage of the Pennsylvanian, the youngest subsystem of the Carboniferous. The Gzhelian lasted from to Ma. It follows the Ka ...

) and is followed by the Permian

Epoch. The name "Cisuralian" was proposed in 1982, and approved by the International Subcommission on Permian Stratigraphy in 1996. The Cisuralian Epoch is named after the western slopes of the Ural Mountains in Russia and Kazakhstan. Limestones on the edge of Russian Platform and make up the Ishimbay oil fields. These oil fields were vital to the Soviet Union during WW2 when the Germans controlled the oil fields to the west. The International Chronostratigraphic Chart (v2018/07) provides a numerical age of 298.9 ± 0.15 – 272.3 ± 0.5 Mya. The base of the Cisuralian series and the Permian

system A system is a group of interacting or interrelated elements that act according to a set of rules to form a unified whole. A system, surrounded and influenced by its environment, is described by its boundaries, structure and purpose and express ...

is defined as the place in the stratigraphic record where fossils of the conodont '' Streptognathodus isolatus'' first appear. The global reference profile for the base (the GSSP or golden spike) is located in the valley of the Aidaralash River, near Aqtöbe in the Ural Mountains of Kazakhstan.

Geography

Gondwana Gondwana () was a large landmass, often referred to as a supercontinent, that formed during the late Neoproterozoic (about 550 million years ago) and began to break up during the Jurassic period (about 180 million years ago). The final sta ...

collided with Laurussia and created the

Alleghenian orogeny The Alleghanian orogeny or Appalachian orogeny is one of the geological mountain-forming events that formed the Appalachian Mountains and Allegheny Mountains. The term and spelling Alleghany orogeny was originally proposed by H.P. Woodward in 195 ...

in present-day North America. In northwestern Europe, the

Hercynian orogeny The Variscan or Hercynian orogeny was a geologic mountain-building event caused by Late Paleozoic continental collision between Euramerica (Laurussia) and Gondwana to form the supercontinent of Pangaea. Nomenclature The name ''Variscan'', comes f ...

continued. This created the large supercontinent,

Pangea 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 ...

, by the middle of the early Permian, which was to have an impact on the climate.

Climate

At the start of the Permian, the Late Palaeozoic Ice Age, which began in 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 ''Carboniferou ...

, as at its peak.

Glaciers A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such as ...

receded over the course of the late Cisuralian as the Earth's climate gradually warmed, particularly during the Artinskian Warming Event, drying the continent's interiors.Palaeos: Life Through Deep Time > The Permian Period
Accessed 1 April 2013. The pan-tropical belt of Pangaea experienced particularly significant aridification during this epoch.

Biodiversity

The swampy fringes were mostly ferns, seed ferns, and lycophytes. The series saw the appearance of beetles and flies. The coal swamps from the

continued and the herbivores,'' Diadectes ''and ''

Edaphosaurus ''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 ...

''. The dry interior with small insectivores. Caseids and prototherapsid'' Tetraceratops'' made their appearance. The marine life was probable more diverse than modern times as the climate warmed. Unusual sharks such as ''

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 ...

'' continued in this series. Early Permian terrestrial faunas were dominated by pelycosaurs, diadectids, 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, arbo ...

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. The pelycosaurs appeared during the

Late Carboniferous Late may refer to: * LATE, an acronym which could stand for: ** Limbic-predominant age-related TDP-43 encephalopathy, a proposed form of dementia ** Local-authority trading enterprise, a New Zealand business law ** Local average treatment effe ...

, and reached their apex in the Cisuralian remaining the dominant land animals for some 40 million years. A few continued into the Capitanian. They were succeeded by the

therapsid 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 ...

s. File:Dimetrodon grandis.jpg, ''

Dimetrodon ''Dimetrodon'' ( or ,) meaning "two measures of teeth,” is an extinct genus of non-mammalian synapsid that lived during the Cisuralian (Early Permian), around 295–272 million years ago (Mya). It is a member of the family Sphenacodont ...

'', a

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 ...

, was at the top of the food chain in the Cisuralian File:Helicoprion bessonovi cropped.png, ''

bessonovi'' with characteristic 'tooth-whorl' at front of jaw

Subdivisions

Global

* Asselian stage (298.9 ± 0.15 – 294.6 ± 0.8 Mya) * Sakmarian stage (294.6 ± 0.8 – 290.1 ± 0.7 Mya) * Artinskian stage (290.1 ± 0.7 – 283.5 ± 0.7 Mya) * Kungurian stage (283.5 ± 0.7 – 272.3 ± 0.5 Mya)

Regional

*New Zealand **Telfordian (289 – 278 Mya) **Mangapirian (278 – 270.6 Mya)

References

{{Geological history, p, m Geological epochs *01