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 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. The series saw the appearance of beetles and flies 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 and is followed by the Permian Guadalupian 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 Ishimbayoil 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 provides a numerical age of 298.9 ± 0.15 – 272.3 ± 0.5 Mya. The base of the Cisuralian series and the Permian system 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 is located in the valley of the Aidaralash River, near Aqtöbe in the Ural Mountains of Kazakhstan.
At the start of the Permian, the Earth was still in an ice age, which began in the Carboniferous. Glaciers receded around the mid-Permian period as the climate gradually warmed, drying the continent's interiors.
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 Carboniferous continued and the herbivores, Diadectes and Edaphosaurus. The dry interior with small insectivores. Caseids and proto-therapsid Tetraceratops made their appearance. The marine life was probable more diverse than modern times as the climate warmed. Unusual sharks such as Helicoprion continued in this series. bessonovi with characteristic 'tooth-whorl' at front of jaw. Early Permian terrestrial faunas were dominated by pelycosaurs, diadectids and amphibians, The pelycosaurs appeared during the Late Carboniferous 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 therapsids.
