Xingxueanthus: An Enigmatic Jurassic Seed Plant and Its Implications for the Origin of Angiospermy  

作　　者：WANG Xin WANG Shijun 

机构地区：[1]Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China [2]Fairylake Botanical Garden, Shenzhen 518004, China [3]State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China

出　　处：《Acta Geologica Sinica(English Edition)》2010年第1期47-55,共9页地质学报（英文版）

基　　金：supported by National Natural Science Foundation of China Programs (No. 40772006, 30670140, 40372008, 40632010 and J0630967),the State Key Laboratory of Systematic and Evolutionary Botany at the Institute of Botany, and SRF for ROCS, SEM

摘　　要：The origin of angiosperms has been tantalizing botanists for centuries. Despite the efforts of palaeobotanists, most of the pre-Cretaceous angiosperms are regarded either non-convincing or misdated. The applications of SEM and LM （light microscope） enable us to recognize a coalified fossil plant, Xingxueanthus sinensis gen. et sp. nov., from the Haifanggou Formation （Middle Jurassic, 〉160 Ma） in western Liaoning, China. Xingxueanthus is an ＂inflorescence＂ with more than 20 female units spirally arranged. Each female unit is situated in the axii of a bract. The female unit is composed of an ovule-container and a style-like projection at the top. There is a vertical column bearing several ovules in the ovule-container. The general morphology and the internal structure of Xingxueanthus distinguish itself from any known fossil and extant gymnosperms, and its structures are more comparable to those of angiosperms. Xingxueanthus, if taken as a gymnosperm, would represent a new class, demonstrate an evolutionarily advanced status of ovule-protection in gymnosperms never seen before, and provide new insights into the origin of angiospermy. Alternatively, if taken as an angiosperm, together with Schmeissneria, it would increase the diversity of Jurassic angiosperms, which has been underestimated for a long time, and suggest a much earlier origin of angiospermy than currently accepted.The origin of angiosperms has been tantalizing botanists for centuries. Despite the efforts of palaeobotanists, most of the pre-Cretaceous angiosperms are regarded either non-convincing or misdated. The applications of SEM and LM （light microscope） enable us to recognize a coalified fossil plant, Xingxueanthus sinensis gen. et sp. nov., from the Haifanggou Formation （Middle Jurassic, 〉160 Ma） in western Liaoning, China. Xingxueanthus is an ＂inflorescence＂ with more than 20 female units spirally arranged. Each female unit is situated in the axii of a bract. The female unit is composed of an ovule-container and a style-like projection at the top. There is a vertical column bearing several ovules in the ovule-container. The general morphology and the internal structure of Xingxueanthus distinguish itself from any known fossil and extant gymnosperms, and its structures are more comparable to those of angiosperms. Xingxueanthus, if taken as a gymnosperm, would represent a new class, demonstrate an evolutionarily advanced status of ovule-protection in gymnosperms never seen before, and provide new insights into the origin of angiospermy. Alternatively, if taken as an angiosperm, together with Schmeissneria, it would increase the diversity of Jurassic angiosperms, which has been underestimated for a long time, and suggest a much earlier origin of angiospermy than currently accepted.

关 键 词：ANGIOSPERM FLOWER ORIGIN LIAONING JURASSIC 

分 类 号：Q949.408[生物学—植物学] P534.52[天文地球—古生物学与地层学]