Editing Cambrian (section)

==== Miaolingian ====
[[File:Diorama of the Burgess Shale Biota (Middle Cambrian) - sponges, arthropods (44691571505).jpg|thumb|250px|Diorama of the [[Paleobiota of the Burgess Shale|Burgess Shale Biota]]]]
The [[Miaolingian]] is the third series/epoch of the Cambrian, lasting from c. 506.5 Ma to c. 497 Ma, and roughly identical to the middle Cambrian in older literature.<ref>{{cite journal |url=https://www.tandfonline.com/doi/full/10.1080/11035897.2019.1621374 |last=Nielsen |first=Arne Thorshøj |title=The Miaolingian, a new name for the 'Middle' Cambrian (Cambrian Series 3): identification of lower and upper boundaries in Baltoscandia |journal=GFF |volume=141 |issue=2 |pages=162–173 |date=October 3, 2019 |doi=10.1080/11035897.2019.1621374 |bibcode=2019GFF...141..162N |access-date=January 2, 2025}}</ref> It is divided into three stages: the [[Wuliuan]] c. 506.5 Ma to 504.5 Ma; the [[Drumian]] c. 504.5 Ma to c. 500.5 Ma; and the Guzhangian c. 500.5 Ma to c. 497 Ma.<ref name="ICS" /> The name replaces Cambrian Series 3 and was ratified by the IUGS in 2018.<ref name="Zhao-2019">{{Cite journal |last1=Zhao |first1=Yuanlong |last2=Yuan |first2=Jinliang |last3=Babcock |first3=Loren E. |last4=Guo |first4=Qingjun |last5=Peng |first5=Jin |last6=Yin |first6=Leiming |last7=Yang |first7=Xinglian |last8=Peng |first8=Shanchi |last9=Wang |first9=Chunjiang |last10=Gaines |first10=Robert R. |last11=Esteve |first11=Jorge |last12=Tai |first12=Tongsu |last13=Yang |first13=Ruidong |last14=Wang |first14=Yue |last15=Sun |first15=Haijing |date=2019-06-01 |title=Global Standard Stratotype-Section and Point (GSSP) for the conterminous base of the Miaolingian Series and Wuliuan Stage (Cambrian) at Balang, Jianhe, Guizhou, China |journal=Episodes Journal of International Geoscience |language=en |volume=42 |issue=2 |pages=165–184 |doi=10.18814/epiiugs/2019/019013|doi-access=free }}</ref> It is named after the Miaoling Mountains in southeastern [[Guizhou|Guizhou Province]], South China, where the GSSP marking its base is found. This is defined by the first appearance of the [[Oryctocephalidae|oryctocephalid]] trilobite ''[[Oryctocephalus indicus]]''. Secondary markers for the base of the Miaolingian include the appearance of many [[acritarch]]s forms, a global [[marine transgression]], and the disappearance of the polymerid trilobites, ''Bathynotus'' or ''Ovatoryctocara.'' Unlike the Terreneuvian and Series 2, all the stages of the Miaolingian are defined by GSSPs''.''<ref name="Zhao-2019" />

The [[Olenelloidea|olenellids]], [[Eodiscidae|eodiscids]], and most [[Redlichiida|redlichiids]] trilobites went extinct at the boundary between Series 2 and the Miaolingian. This is considered the oldest mass extinction of trilobites.<ref name="Peng-2020" />