[关键词]
[摘要]
五通组广泛分布于长江下游地区苏、浙、皖一带。近几十年的古植物学研究工作, 使得五通植物群成为全球晚泥盆世属种最为丰富的植物群之一。安徽巢湖狮子口剖面的五通组出露良好, 植物化石丰富。然而, 正式描述及图示的植物仅包括石松类Bothrodendron anhuiense Cai et Wu、Sublepidodendron grabaui (Sze) Wang et Xu、Sublepidodendron songziense Chen和楔叶类Sphenophyllum lungtanense Gothan et Sze。本文对狮子口剖面五通组中的晚泥盆世植物化石进行了再研究, 计有石松类植物Stigmaria ficoides Brongniart、Stigmaria rugulosa Gothan、Sublepidodendron songziense、Sublepidodendron grabaui和Lepidostrobophyllum sp., 以及楔叶类植物Eviostachya hoegii Stockmans和Hamatophyton verticillatum Gu et Zhi。一些石炭纪的全球常见植物如Bothrodendron Lindley et Hutton、Sphenophyllum Brongniart及Sublepidodendron (Nathorst) Hirmer等已出现在狮子口剖面上泥盆统五通组中, 表明华南很可能是这些类群辐射与演化的中心之一。
[Key word]
[Abstract]
The Wutong Formation is widespread in the lower reaches of the Yangtze River, including Jiangsu, Zhejiang and Anhui provinces. Paleobotanical studies during the past decades have revealed that the Wutong flora is one of the most species-rich Late Devonian floras. The Wutong Formation at the Shizikou section of Chaohu, Anhui Province is well-exposed and bears rich plant fossils. Numerous plants have been previously reported from this section, including Bothrodendron anhuiense Cai et Wu, Bothrodendron cf. kiltorkense, Eolepidodendron wusihense (Sze) Wu et Zhao, Eolepidodendron cf. wusihense, Hamatophyton verticillatum Gu et Zhi, Lepidodendropsis dzungariensis Sze, Lepidodendropsis hirmeri Lutz, Lepidostrobus grabaui Sze, Sphenophyllum lungtanense Gothan et Sze, Sphenophyllum pseudotenerrimum Sze, Stigmaria radiatopunctata Gothan et Sze, Sublepidodendron mirabile (Nathorst) Hirmer, Aphyllopteris sp., Archaeopteris sp., Bothrodendron sp., Hamatophyton sp., Paleostachya sp., Rergeria sp., Rhodea? sp., Sphenopteridium sp., and Sublepidodendron sp. However, most of these plants are only listed in general introductions of the Shizikou section without illustrations and formal descriptions. Therefore, their exact occurrences remain unverified. Three lycopsids, i.e., Bothrodedron anhuiense, Sublepidodendron grabaui (Sze) Wang et Xu, and Sublepidodendron songziense Chen, and one sphenopsid, i.e., Sphenophyllum lungtanense are the only plants from the Shizikou section that have been illustrated in previous publications. In this paper, we describe the lycopsids, including Stigmaria ficoides Brongniart, Stigmaria rugulosa Gothan, Sublepidodendron songziense, Sublepidodendron grabaui and Lepidostrobophyllum sp., and the sphenopsids, including Eviostachya hoegii and Hamatophyton verticillatum, from the Shizikou section. The new materials show that Sublepidodendron songziense and Sublepidodendron grabaui are the two dominant components in the Wutong Formation at the Shizikou section. These two species are different from each other in shape and size of leaf bases. Stigmaria ficoides and Stigmaria rugulosa show helically arranged rootlet scars on the surface of the rhizomorphs. The oval-shaped sporophylls of Lepidostrobophyllum sp. are detached and preserved with or without a medial groove. New specimens of Eviostachya hoegii exhibit “sporangiophore” dividing multiple times with terminal sporangia. Specimens of Hamatophyton verticillatum demonstrate isotomously or anisotomously branching patten. Arborescent lycopsids are predominant in the Shizikou section, probably forming early forest ecosystems. Most genera from the Shizikou section are cosmopolitan, while Hamatophyton is endemic. Most plants from the Shizikou section have also been reported from other localities of the Wutong Formation. Bothrodendron, Sphenophyllum and Sublepidodendron are common in the Carboniferous, and their earlier occurrences in the Upper Devonian Wutong Formation at the Shizikou section implies that the South China Block is one of the centers of origin and radiation of these groups.
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[基金项目]
国家自然科学基金(41802003)、江苏省自然科学基金(BK20181108)和中国科学院战略性先导科技专项(B类) (XDB26000000)联合资助