New data of early Late Ordovician chitinozoans from the Miaopo Formation at Jieling, Yichang, central China

Abstract

Chitinozoans from the uppermost Darriwilian–lower Sandbian Miaopo Formation at Jieling of western Hubei Province are reported, for the first time, including 30 species of 14 genera from 10 collections which are much more diverse and abundant than previously known. Two chitinozoan assemblages are recognized: the Laufeldochitina cf. striata Assemblage and the Eisenackitina cf. rhenana Assemblage. The L. cf. striata Assemblage is correlative to the upper Hustedograptus teretiusculus graptolite biozone. The base of the E. cf. rhenana Assemblage coincides with the base of the Nemagraptus gracilis graptolite biozone, indicating that E. cf. rhenana has the potential for recognizing the base of Upper Ordovician.

Keywords::

• chitinozoans
• Middle–Upper Ordovician
• the Miaopo Formation
• Jieling section
• Yichang
• central China

Acknowledgements

Our sincere thanks are to LIU Jianbo (for the help in the field) from Peking University, FENG Limei (for help in the laboratory) and FAN Xiaoyi (for help with the SEM photos) from Nanjing Institute of Geology and Palaeontology, CAS. Two reviewers, Dr. Susana de la Puente and an anonymous expert, and the Journal Editors, Mickael Calner and Guillermo Albanesi, provided constructive comments and substantial help that make the manuscript a much better shape. Financial supports are from the National Natural Science Foundation of China (grant numbers 41172012, 41221001, 41290260). This article is a contribution to the IGCP project 591 (The Early to Middle Paleozoic Revolution).