Miaolingian

The Miaolingian or Mid-Late Cambrian is the third Series of the Cambrian Period, and was named in 2018. It lasted from about 506.5 to 497 million years ago and is divided into three stages: the Wuliuan, Drumian, and Guzhangian.

This time saw many important changes in life and the environment on Earth.

The Miaolingian is named after the Miaoling Mountains in southeastern Guizhou Province, China. This name helps scientists remember where the idea for this time period came from. The Miaolingian comes after the unnamed Cambrian Series 2 and is followed by the Furongian series.

This part of the Cambrian is very important for understanding how life evolved on our planet. Many new types of animals appeared. Scientists study rocks and fossils from this time to learn more about Earth's early history.

Definition

The Miaolingian is a time period from about 506.5 to 497 million years ago. It was named in 2018. Scientists used fossils to decide when this period began and ended. They picked a special fossil called Oryctocephalus indicus to mark the start. This fossil was found in the Kaili Formation in Guizhou, China. The end of the Miaolingian is marked by another fossil, Glyptagnostus reticulatus, that appeared about 497 million years ago.

Subdivision

The Miaolingian has three main parts: the Wuliuan, Drumian, and Guzhangian. These parts help scientists learn about events from long ago. There was another part called the Ordian, used mostly in Australia. Scientists are still figuring out where it fits in the timeline.

Major events

During a time called the Cambrian Series 2–Miaolingian boundary, many ancient sea creatures called trilobites went extinct. This was the first big loss of trilobites, especially families like Ollenellidae and Redlichiidae in places such as Laurentia and South China. After this extinction, a new kind of trilobite called O. indicus appeared. Where fossils of O. indicus are not found, scientists use special chemical clues in rocks to find this boundary.

Paleontology

During the Miaolingian time period, many sea creatures called graptolites lived all over the world. These graptolites were small, plant-like animals that built colonies together. Two families, Rhabdopleuridae and Dithecodendridae, started to change and evolve early in this time. One common graptolite from the Wuliuan stage was called Sphenoecium. Its strong colonies have been found in many places around the world.