Phragmodictya jinshaensis sp. nov., a hexactinellid dictyosponge from the Cambrian of Jinsha, south China

Abstract

A new fossil species from Cambrian strata of Jinsha, south China, is interpreted as the earliest known hexactinellid dictyosponge. Phragmodictya jinshaensis sp. nov. occurs within the Niutitang Biota, the oldest known Burgess Shale-type biota. The new species is characterized by a convex, disc-shaped body consisting of reticular skeletal network surrounded by frill-bearing radial ridges. The discovery of this sponge is unexpected and provides additional evidence bearing on the nature of Precambrian sponges and the early evolution of hexactinellid dictyosponges. It also invites re-evaluation of the taxonomy of both Ediacaran and Phanerozoic sponges.

Keywords::

• hexactinellid dictyosponge
• Cambrian
• Jinsha, south China

Acknowledgements

This research was supported by the National Natural Sciences Foundation of China (Nos. 41362002, 40902003, 41172005), National Basic Research Program of China (2013CB835002), Guizhou Natural Science Foundation (No. Gui J. 2011-2035) and State Key Laboratory of Palaeobiology and Stratigraphy (Nanjing Institute of Geology and Palaeontology, CAS) (No. 113109). Special thanks are due to Zhao Jian, Liu Chao and Yang Zhongqun from Guizhou University for assistance in the field, Chen Zhouqing from Nanjing Institute of Geology and Palaeontology, and Chinese Academy of Sciences for photograph of fossils. Two anonymous reviewers provided critical comments, and Heyo Van Iten of Hanover College improved the English writing of the manuscript.