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The Wuliuan stage is the fifth stage of the Cambrian, and the first stage of the Miaolingian Series of the Cambrian. It was formally defined by the ICS in 2018. Its base is defined by the first appearance of the trilobite species Oryctocephalus indicus; it ends with the beginning of the Drumian stage, marked by the first appearance of the trilobite Ptychagnostus atavus around 504.5 million years ago.
Three sections are currently discussed as GSSP candidates: the Wuliu-Zengjiayan section near Balang in Guizhou province (China), a section on Split Mountain in Nevada (USA) and the "Molodo river section" along the Molodo river. The Wuliu-Zengjiayan section is an outcrop of the Kaili Formation in the Wuliu quarry. The first candidate for the beginning of Stage 5 is the trilobite Oryctocephalus indicus, the second candidate is the trilobite Ovatoryctocara granulata.
- "ChronostratChart2018-08" (PDF).
- "GSSP Table - Paleozoic Era". Retrieved 15 November 2012.
- "ISCS Annual Report 2017.pdf" (PDF).
- "The 13th International Field Conference of the Cambrian Stage Subdivision Working Group" (PDF). Episodes. 31 (4): 440–441.
- Sundberg, F.A.; Zhao, Y.L.; Yuan, J.L.; Lin, J.P. (22 September 2011). "Detailed trilobite biostratigraphy across the proposed GSSP for Stage 5 ("Middle Cambrian" boundary) at the Wuliu-Zengjiayan section, Guizhou, China". Bulletin of Geosciences: 423–464. doi:10.3140/bull.geosci.1211.