Xue, Jinzhuang , Hao, Shougang .
A zosterophyll-dominated plant assemblage from the Lower Devonian (Lochkovian) Xitun Formation of Yunnan, China.
Plant fossil records from the Early Devonian Lochkovian deposits still remain very patchy around the world, especially those of South China, where only few species has been reported. In previous reports, we described three species of Zosterophyllum separately from the Yulongsi Formation (Pridoli, Late Silurian), the Xiaxishancun Formation (early Lochkovian, Early Devonian), and the Xitun Formation (mid-late Lochkovian) of Qujing, Yunnan, China. As a subsequent work, this study described a plant assemblage with nine plants from the Xitun Formaiton, among which at least six species are of zosterophyll affinity. Two species of the genus Zosterophyllum (Z. sp. and Z. minorstachyum) and four plants with spirally arranged sporangia (such as Xitunia spinitheca, Gen. nov. A, cf. Huia sp., and Zosterophyllopsida indet. A), thus also showing a zosterophyll affinity, are described. Taeniocrada sp. shows close relationship with zosterophylls because of its K- or H-shaped branching pattern. Only two specimens represent a probable rhyniophytoid. The axes of Uncatoella verticillata, which was considered a dasycladalean alga, are very common in this assemblage. This plant assemblage shows large taxonomic and morphological diversity, especially concerning sporangial morphology. These plants show diverse fertile morphologies and add new data on the diversity of plants in the Lochkovian. Different from the condition of the coeval assemblages from higher latitudes, which are mainly composed of rhyniophytoids, the plant assemblage of the Xitun Formation is dominated by zosterophylls.
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1 - School of Earth and Space Sciences, Peking University, Beijing 100871, P.R. China
Presentation Type: Oral Paper:Papers for Sections
Location: 555B/Convention Center
Date: Monday, August 2nd, 2010
Time: 1:45 PM