Late Darriwilian-early Katian (Ordovician) ostracods of northeastern Yunnan, Southwest China

Ordovician silicified ostracods of the western Yangtze Platform, South China, are documented for the first time from the Huadan Formation of Qiaojia County, northeastern Yunnan Province, Southwest China. Twenty-one species of 17 genera are identified with new taxa including Vendona spinifera n. sp. and Nikitinella songliangensis n. sp. These two species, together with Medianella gigantea are the most common constituents of the fauna. Faunal comparison shows close connections between South China, Baltica, the Argen-tine Precordillera, Kazakhstan, Tarim, and Sibumasu during this time interval. This fauna is considered to be related to a nearshore carbonate environment, and biostratigraphical analysis of it supports a late Darriwilian to early Katian age for the Huadan Formation.(c) 2023 Elsevier B.V. and Nanjing Institute of Geology and Palaeontology, CAS. All rights reserved.

Automated summary

The first record of silicified ostracods from the Huadan Formation in Qiaojia County, Yunnan Province, Southwest China, is presented. A total of 21 species belonging to 17 genera have been identified, including two new taxa. Faunal comparison indicates close connections with other regions during the examined time interval. The fauna is associated with a nearshore carbonate environment, and the biostratigraphical analysis suggests a late Darriwilian to early Katian age for the Huadan Formation.