New Material Of Elatocladus And Its Associated Sporopollen And Other Plant Fossils From Lower Cretaceous Shahezi Formation Of Changtu In Liaoning,China

The Lower Cretaceous strata in eastern margin of the Songliao basin are rich in yielding oil,coal and other fossil fuel mineral resources,in which the Lower Cretaceous Shahezi Formation is an important part of the strata.Shahezi of Changtu in Liaoning,is the stratotype section site of the Shahezi Formation,and therefore the study of its mega-plant and sporopollen fossils is very significant for paleobotany and geology.Elatocladus,as a common genus in conifers,is widely distributed in the Mesozoic strata from Northeast China.However,the taxonomy of this genus and its use in classification have been controversial for a long time,due to the lack of research on its reproductive organs and cuticles.Based on the new materials collected by the author in the Lower Cretaceous Shahezi Formation in Shahezi of Changtu,the leaf cuticles of Elatocladus submanchurica are studied comprehensively for the first time,in which the author found that the cuticles of this taxon are amphistomatic in type,and disoriental in stomata.In gross morphology,the taxon E.submanchurica is also much different from E.manchurica,the well-known Jurassic taxon in the Mesozoic floras.Thus,the author has suggested that E.submanchurica is an independent species of Elatocladus,and its specific name should be used continuously and independently.The achievement would be very significant for the taxonomic study of the genus Elatocladus.Besides,the author has also found sporopollen and other mega-plant fossils associated with the fossil Elatocladus,from the studied beds and locality.The synthetic study suggests that it was probably a warm temperate climate and in humid and semi-humid environment during the Shahe Formation deposits in the Early Cretaceous.The achievement would enrich the knowledge on the composition and ecology of the Early Cretaceous flora from the Shahezi Formation.In sum,this paper has reported a detailed study of the leaf cuticles of Elatocladus submanchurica in Northeast China for the first time,promoting the research level of taxonomy of Elatocladus.Meanwhile,the synthetic study of Elatocladus with its associated sporopollen and other mega-plant fossils,would put forward the in-depth study of the Shahezi Formation in regional correlation and sedimental environment during the Early Cretaceous.