The Ediacaran macroalga Zhongbaodaophyton Chen et al. from South China

Abstract

Wang, Y., Wang, Y., Du, W. & Xang, X., 13.2.2015. The Ediacaran macroalga Zhongbaodaophyton Chen et al. from South China. Alcheringa 39, xxx–xxx. ISSN 0311-5518Zhongbaodaophyton Chen et al. (including two species Z. crassa Chen et al. and Z. robustus Wang et al.) is an Ediacaran macroscopic genus in the Wenghui biota from black shales of the upper Doushantuo Formation (ca 551–593 Ma) in northeastern Guizhou, South China. Zhongbaodaophyton has an unequally dichotomous thallus and a robust holdfast, resembling phaeophytes in morphology; however, its cytological features are not determinable from the carbonaceous compression fossils. Its thallus bears at least nine photosynthetic branches, and its holdfast consists of a globose tuberous rhizome with many unbranched or dichotomous filamentous rhizoids. In addition, these Ediacaran macroalgal species bear pith in the stipe and tuberous rhizome, which is a key feature of phaeophytes. Based on the measurements of 129 Z. robustus specimens, the degree of branching is closely related to the thallus length, the stipe width, and the width ratio of two primary branches; and the stipe width is correlated with the thallus length, the two primary branch widths, and the first branching angle. The thallus grew primarily upward to enhance its competitiveness for sunlight and/or nutrient uptake in the Ediacaran marine ecosystem. A turning point toward reduced growth rates may have occurred in the life history of Z. robustus individuals (at the fourth or fifth axial bifurcation).Yue Wang [gzyuewang@126.com], School of Resources and Environments, Guizhou University, Guiyang 550003, PR China; Ye Wang [gboywangye@126.com] and Xunlian Wang [wxl@cugb.edu.cn], School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, PR China; Wei Du [duwei@ea.c.u-tokyo.ac.jp], Department of Earth Science and Astronomy, The University of Tokyo, Tokyo 153-8902, Japan.