New trilobite association over 400 mln years ago found in Yunnan

Photo shows the newly documented trilobite association during the Late Ordovician discovered in Zhenxiong County, southwest China's Yunnan Province. (Xinhua)

Chinese scientists have documented a new trilobite association during the Late Ordovician in Zhenxiong County, southwest China's Yunnan Province.

The discovery by researchers from Peking University, Nanjing Institute of Geology and Palaeontology under the Chinese Academy of Sciences and Xi'an Geological Survey Center was recently published in Palaeoworld.

The trilobite association includes 17 species of 15 genera, among which four species are new, according to Wei Xin, one of the researchers from Peking University.

Photo shows the newly documented trilobite association during the Late Ordovician discovered in Zhenxiong County, southwest China's Yunnan Province. (Xinhua)

Scientists said that the discovery will provide a great opportunity for researchers to investigate the marine organisms in southern China during the Late Ordovician.

Based on the distribution of trilobite species, it is reasonable to infer that a migration event took place in southern China before the end-Ordovician mass extinction, said Wei.

Affected by tectonic movement, the marine environments of southern China's palaeoplate gradually deteriorated, forming an anoxic semi-enclosed basin, which led to the extinction of most of the trilobites. Only a few trilobites migrated to "shelters" in relatively shallower and oxygenated environments, such as Zhenxiong, Wei added. ■