| Abstract Detail
Paleobotanical Section Hao, Shougang [1], Xue, Jinzhuang [1], Wang, Deming [1]. Zosterophyllum Penhallow around the Silurian-Devonian boundary of northeastern Yunnan, China and its phytogeographic implications. TWO new species of Zosterophyllum Penhallow (Z. qujingense sp. nov. and Z. xishanense sp. nov.) from respectively Yulongsi Formation (Late Silurian, Přídolí) and Xiaxishancun Formation (Early Devonian, Lochkovian), Qujing, Yunnan, China are described. Both are small and naked plants. At present Z. qujingense is the earliest recorded plant of Zosterophyllum in South China. It has basal H- or K-shaped branching and erect dichotomous axes. Terminal spikes consist of lateral and stalked sporangia of wedge or somewhat elliptical shape. Arising from the rhizome, fertile axes of Z. xishanense bear laterally stalked and more or less round sporangia. Based on well-preserved material, configuration of the rhizomatous part and K- or H-shaped branching of Z. xishanense are discussed. Comparison with other zosterophylls, particularly those of the Late Silurian in Bathurst Island, Canada, indicates that the Late Silurian–Early Devonian flora of the paleoequatorial zone (i.e. Bathurst Island and Qujing, Yunnan) may be characterized by a diversity of zosterophylls, probably differing from coeval floras of other regions dominated by rhyniophytoids. With regard to paleophytogeography, the zosterophylls bearing radially arranged sporangia (including subgenus Zosterophyllum) were prevalent in South China Block (northeastern Gondwana phytogeographic unit) and those with one or two rowed sporangia (subgenus Platyzosterophyllum) were dominant on the Laurussian paleocontinent.
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1 - School of Earth and Space Sciences, Peking University, Beijing 100871, P.R. China,
Keywords:
Zosterophyllum
Late Silurian
Early Devonian
Qujing
Yunnan.
Presentation Type: Oral Paper:Papers for Sections
Session: 5-1
Location: 266/Holt
Date: Monday, July 31st, 2006
Time: 8:15 AM
Abstract ID:118 |
