【作者】 董曼；

【导师】 孙革；

【作者基本信息】 吉林大学 ， 古生物学与地层学， 2008， 硕士

【摘要】 白垩世早期是银杏属(Ginkgo)在地史时期演化和分异一个重要时期。对该属化石的研究在研究银杏类系统分类与演化中占有重要地位。内蒙古东部霍林河煤田早白垩世银杏属化石十分丰富,多保存完好。本文通过对银杏属化石叶部角质层的形态解剖学研究,详细描述了霍林河煤田早白垩世霍林河组采得的一些新材料,并与以往发现于本区的革质银杏(Ginkgo coriacea Florin)等做了详细的比较,补充了对G. coriacea形态及解剖特征的认识;与此同时,提出外部形态在分类研究工作中同样不容被忽视。此外,作者还发现了Ginkgo sp.新材料,该种分裂次数多,且分裂较深,末级裂片较窄,叶片上下表皮均普遍发育毛状体,它可能是银杏属的一个新的种级分类群。上述研究在一定程度上提高了本区银杏属化石的分类研究水平,对深入研究早白垩世早期银杏属在霍林河地区的发展演化等,具有重要意义。此外,结合植物群特征,本文也对本区早白垩世的古气候及古地理进行了总体上的分析和论述,认为早白垩世早期或早中期本区可能处于温暖潮湿具季节性变化的暖温带。上述成果为深入研究霍林河地区早白垩世时期古地理、古气候等补充了新的资料。更多还原

【Abstract】 Early Cretaceous is an important period for the evolution and early diversity of Ginkgo. The study of the Early Cretaceous Ginkgo, as well as its associated Ginkgoaleans, plays an important role for study of the earlier evolution and evolutionary history of Ginkgo.The Early Cretaceous Ginkgo leaves from Huolinhe in Inner Mongolia, China are rich in composition and well-preserved in cuticles. In this thesis the author made anatomic study of the fossil leaves of Ginkgo, mainly in cuticle study and described some new material of Ginkgo, which provided new and supplementary data for better understanding the known species of Ginkgo reported before. Moreover, the author found also a new taxon, Ginkgo sp., in which the leaves are deeply dissected into thin and narrow lobes with well-developed trichomes in both epidermal surfaces, and show probably a new species of Ginkgo. The above-mentioned results of the present study appear to benefit the improvement for the taxonomic research level of fossil Ginkgo, and are significant for further study of the evolution of Ginkgo in northeastern China during the Early Cretaceous time.In addition, the author analyzes the paleoclimate and paleophyto- geography in the Huolinhe area in Early Cretaceous, and suggest that the paleoclimate of this area might be seasonally warm and humid during the Early Cretaceous time.更多还原