Home | Contact | Sitemap | 中文 | CAS
Search: 
About Us Research People Cooperation News Education & Training Join Us Societies & Publications Newsletter Resources Links
 
Research
Research Progress
Research Divisions
Supporting System
Achievements
Research Programs
How to Join Us
  Location: Home > Research > Research Progress
Early–Mid Ordovician Yangtzeella (Syntrophiidina, Brachiopoda) and its evolutionary significance
       Updatetime: 2010-07-14 Printer      Text Size:A A A 
by ZHAN RENBIN*, JISUO JIN† and PENGFEI CHEN†
 *State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China; e-mail rbzhan@nigpas.ac.cn 
 †Department of Earth Sciences, University of Western Ontario, London, ON N6A 5B7, Canada; e-mail jjin@uwo.ca
Copyright © The Palaeontological Association, 2010
KEYWORDS: Yangtzeella • ornamentation • macroevolution • Ordovician • South China
Abstract: Re-examination of newly collected topotype material confirms that the type species of Yangtzeella, Y. poloi, a widespread Early and Mid Ordovician syntrophiidine brachiopod in South China, has a finely costellate shell rather than being smooth as previously thought. Thus, the subgenus Yangtzeella (Vadimella) Nikitina et al., established on the basis of fine costellae, is invalidated. Among 15 species of Yangtzeella, five species are recognized as valid based on multivariate analyses: Y. poloi, Y. unsulcata, Y. songziensis, Y. kueiyangensis and Y. igori, among which the type species was the oldest known. Six are synonymized: Y. septata, Y. reticulata, Y. lensiformis, Y. depressa, Y. yichangensis and Y. minuta. Four are rejected from Yangtzeella: Y. extensa, Y. similior, Y. yohi and Y. poloi var. minor. Regional biostratigraphy indicates that Yangtzeella first appeared in a relatively deep-water setting on the Lower Yangtze Platform (South China palaeoplate) during late Tremadoc time (Scolopodus warendensis conodont biozone) and then expanded to the deeper Jiangnan Slope as well as to the shallower Upper Yangtze Platform. The genus experienced two episodes of heightened abundance and diversity on the Upper Yangtze Platform during late Dapingian and mid Darriwilian times, respectively. Outside South China, Yangtzeella occurs sporadically in a few microplates or terranes, such as Tarim, Chu-Ili (southern Kazakhstan) and Taurides (southern Turkey) during the Dapingian and Darriwilian. Worldwide, Yangtzeella became extinct by the end of the Darriwilian.
 
Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences
No.39 East Beijing Road ,Nanjing 210008, CHINA Phone: 0086-25-83282105 Fax: 0086-25-83357026 Email: ngb@nigpas.ac.cn