Oldest glosselline linguliform brachiopod with soft parts from the Lower Cambrian of Yunnan, Southern China

Abstract

Lingulella chengjiangensis Jin, Huo & Wang, 1993 is one of the most abundant brachiopods from the celebrated Lower Cambrian Chengjiang Lagerstätte. A detailed study of abundant new well-preserved specimens clearly shows that their morphology and preserved soft anatomy differ widely from that of the linguliforms of the subfamily Obolinae, including Lingulella. L. chengjiangensis is herein re-described as the probable earliest member of the subfamily Glossellinae, which was previously known only from the Ordovician, and is referred to the new genus Eoglossa. Eoglossa chengjiangensis differs from species of Lingulella in lacking a dorsal pseudointerarea, having an elevated ventral proparea without flexure lines, and in the lack of pitting on the visceral areas of both valves. The detailed study of the exceptionally preserved specimens of E. chengjiangensis also reveals that it bears a unique musculature, which includes a single umbonal scar and a pair of posterolateral scars on each valve. The material of E. chengjiangensis also permits a more detailed study of the pedicle giving further insights into the early diversification and life habit of the linguliform brachiopods.

Keywords::

• brachiopod
• lingulids
• Obolidae
• Glossellinae
• Lower Cambrian

Acknowledgments

The authors specially thank Prof. Guoxiang Li for various suggestions and kind help, Dongjing Fu for beneficial discussions and Illiam Jackson and Nicolas Campione for linguistic advice. The authors thank two anonymous reviewers and the editor Christian B. Skovsted for valuable comments. The authors also thank Zhiliang Zhang and Juanping Zhai for the preparation of the fossils. Fossil collections by Zhang Z.F. in Xi'an, China, are supported by the National Natural Science Foundation (grant 40702005) and Shaanxi Bureau of Science and Technology (2011kjxx37, 2011JZ006), the Fok Ying Tung Education Foundation (G121016), grant for New Century Excellent Talents in University and a Foundation for the Author of National Excellent Doctoral Dissertation of P.R. China (FANEDD). This research is also supported by The Swedish Research Council (to Lars E. Holmer; VR 2009-4395, 2012-1658).