兰州大学机构库 >地质科学与矿产资源学院
甘肃永昌二叠纪楔叶类和真蕨类化石及其原位孢子
Alternative TitleSphenopsida and Filicinae fossils with in situ spores from the Permian of Yongchang, Gansu
孙凡凯
Thesis Advisor孙柏年
2019-04-17
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name硕士
Degree Discipline古生物学与地层学
Keyword永昌 二叠纪 植物化石 原位孢子 古生物地理
Abstract二叠纪是地球历史上陆生维管植物极为重要的发展时期,植物化石以有节类、石松类、真蕨、种子蕨等为主,这一时期对植物系统演化及古地理分布的研究尤为重要。植物化石是植物在地质历史时期的产物,在研究植物的起源、演化以及与环境之间联系中有着无法替代的作用。甘肃永昌地区二叠系中含有丰富的植物化石,这些材料不仅为日后晚古生代植物化石的研究提供了良好的对比材料,同时对研究区的楔叶属及Cyathocarpus的物种多样性、植物古地理学、晚古生代永昌地区植物群样貌、华北,阿拉善与华南地区植物群组成因子之间的交流以及古板块的相对位置的研究具有重要意义。化石材料采自甘肃省金昌市永昌县二叠系乌拉尔统太原组及山西组,通过对化石的形态结构对比与聚类分析相结合的方法,对楔叶类和真蕨类植物大化石(营养叶、生殖叶和孢子穗)进行了系统分类与鉴定。利用原位孢子分析法获得Cyathocarpus的原位孢子团,使用光学及扫描电子显微镜对其微细结构进行了研究。另外,通过统计全球晚古生代的化石记录,探讨了Cyathocarpus及楔叶属的植物古地理学(起源、演化及地史变迁等)等问题。鉴定出甘肃永昌地区乌拉尔统太原组楔叶类2属5种化石:Sphenophyllum spathulatum、S. thonii、S. kawasakii、S. oblongifolium以及Bowmanites yongchangensis sp. nov.。其中包括营养叶和繁殖器官。基于这些楔叶属的新材料,对椭圆楔叶以及马齿楔叶的茎轴表面纵纹、叶片分裂次数等特征进行了修订。同时报道了楔叶穗属1新种Bowmanites yongchangensis sp. nov.,对其孢子囊及孢子叶的形态特征做了详细的描述。此外,本文对研究区乌拉尔统山西组地层中保存完好的真蕨类营养叶与生殖叶进行了深入研究,共鉴定1属1新种:Cyathocarpus yongchangensis sp. nov.。标本的聚合囊由4–5个孢子囊组成,辐射状排列,并以囊柄着生于叶片上。原位孢子较小,直径在21 μm和30 μm之间,为单缝粒面孢,没有保存环带结构。其中,Cyathocarpus的聚合囊及原位孢子的微细结构为华夏植物群中首次获得,补充了晚古生代华夏植物群真蕨类化石繁殖器官的微细结构特征。结合全球大量化石记录,对甘肃永昌地区中的楔叶属以及Cyathocarpus的物种多样性、起源与地理变迁进行讨论。结果表明研究区晚古生代楔叶属及Cyathocarpus呈现出较高的物种多样性,且上述植物均为晚古生代欧美植物群与华夏植物群的共有分子,表明晚古生代欧美与华夏植物群之间存在较为密切的交流。而通过对真蕨类化石不同属的出现时间、聚合囊特征、孢粉学及叶形特征进行对比与讨论,可以推测Cyathocarpus、Zhutheca、Danaea具有较近的亲缘关系,并推测它们的演化顺序为Cyathocarpus-Zhutheca-Danaea。
Other AbstractThe Permian is an important development period in the Earth history. This period has many kinds of plant contained Articulatae, Lycophytes, Filicophytina, Pteridospermae and is significance to study the paleogeographic distribution and systematic paleobotany evolution. Plant fossils are the products of geological history. They are irreplaceable in the study of plant origin, evolution, and rebuilding environment. The Permian in Yongchang, Gansu contains abundant sporopollen and plant fossils. These materials provide a good contrast material for the study of the Late Paleozoic plant in the future. Besides, these fossils are significance for the study of the species diversity of Sphenophyllum and Cyathocarpus in the study area, plant paleogeography, the Late Paleozoic Yongchang flora, the relative position of the paleo-plates, and the compositions exchange among North China, South China and Alashan floras.The fossil materials were collected from in the Cisuralian Taiyuan and Shanxi Formation of Yongchang, Gansu Province. By the macromorphological comparison and cluster analysis, the macrofossils (leaves and reproductive organs of Sphenopsida and Filicinae) were systematically studied. In situ spores of Cyathocarpus were obtained by analysis in the lab. Spore’s microstructures were studied by optical and scanning electron microscopy. In addition, through the statistics of the fossil records in the late Paleozoic, the paleogeography of Cyathocarpus and Sphenophyllum (origin, evolution and geologic change, etc.) was discussed.In the present study, we reported 2 genera and 5 species as Sphenopsida: Sphenophyllum spathulatum、S. thonii、S. kawasakii、S. oblongifolium and Bowmanites yongchangensis sp. nov., including nutrition and reproductive organs. Based on these new materials, we studied the characters of S. kawasakii and S. oblongifolium and revised their species diagnosis. A new species of Bowmanites was reported as Bowmanites yongchangensis sp. nov. Its sporangium and sporophyll were described in detail. In addition, we studied some sterile and fertile fronds from Shanxi Formation, Cisuralian in the study area in detailed. 1 genus 1 new species was identified: Cyathocarpus yongchangensis sp. nov. In particular, synangium and in situ spores were analyzed in the lab. Data showed that the synangium of this species contained four and five radially arranged pedicellate sporangia. The spores of this plant were small, between 21 and 30 μm, monolete and microgranulate with no visible annule. These spore masses and spores in situ of this genus were described in detail at the first time as a component of the Cathaysian flora, which provided some valuable microstructure taxonomic information.Based on the fossil records, we analyzed the diversity, origin and emigration path of Sphenophyllum and Cyathocarpus in the study area. The two genera reported in the Cisuralian from the study area showed a high diversity and both existed in Euramerican and Cathaysia floras in Late Paleozoic, which showed the close communication these floras. Besides, through comparing and discussing the synangium, palynology and leaf shape characteristic with different genera, it was inferred that Cyathocarpus, Zhutheca, Danaea may have a close genetic relationship and their evolution order is Cyathocarpus-Zhutheca-Danaea.
Pages101
URL查看原文
Language中文
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/338426
Collection地质科学与矿产资源学院
Affiliation地质科学与矿产资源学院
First Author AffilicationSchool of Earth Sciences
Recommended Citation
GB/T 7714
孙凡凯. 甘肃永昌二叠纪楔叶类和真蕨类化石及其原位孢子[D]. 兰州. 兰州大学,2019.
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