Three Types Of Tropical Plant Fossils From The Miocene Of Fujian And Their Significance

Over the years,many well preserved fossil plants,especially angiosperm fossils,were successively found in the Miocene of Zhangzhou,Fujian.These plant fossils can provide new insights into the plants evolution.Furthermore,the fossil plants from Zhangpu County will greatly help us to understand the paleoenvironment of Fujian during the Miocene.In this thesis,we systematically described angiosperm fossils from the Miocene Fotan Group.Using the methods of Leaf Architectural Analysis and Schulze Solution,3 genera and 4 species belonging to 3 families are reported: Nerium fujianensis sp.nov.(Apocynaceae),Sabalites sp.(Palmae),Shorea fujianensis(Dipterocarps),and Shorea sp.(Dipterocarps).Most of them are tropical plants.This thesis focus on 4 species of these plants based on gross morphology and microstructure.These species are compared with related extant and the known fossil species.According to the method of Nearest Living Relative species(NLRs),integrated the other related fossil evidences,the phytogeographical history of these 3 genera is discussed.Meanwhile,the paleoclimate of Fujian is explored during the Miocene.The Nerium is little known because of the paucity of the fossil records.The occurrence of Nerium fujianensis not only supplements the fossil records of the Nerium,but also is the first occurrence in Asia.After being compared with related extant and the known fossil species,it is inferred that the Nerium was originated from the tropical areas of Eurasia.Palm and Dipterocarps are both of dominant species of tropical rain forests,they can be used to track rainforest evolution.The Sabalites reported here,not only supplements a new fossil record,but also provides a new important fossil evidence for studying the phytogeographical history of this genus.The winged fruits of Shorea from the Fotan Group have been reported,and the Shorea leaves founded in this article provide comprehensive characteristics to study Shorea plants.The Sabalites and Shorea occurred here,combining with associated plants found in the same sedimentary strata,further proved the existence of tropical rain forests in Zhangpu County.In addition,according to the fossils data of the Nerium,Sabalites and Shorea,it is shown that the 3 genera have a tendency to evolve toward the high latitude after the origin.To the Miocene,the maximum distribution rangehad reached.After the Miocene,the distribution range was gradually reduced because of the cold climate,and formed the modern distribution pattern.The Nerium,Sabalites and Shorea are strong tropical components,and live in the warm and moist environment.Especially,Palms survive in a lot of water condition.Combining with the previous plant fossils,it can be speculated that there is a warm and humid tropical climate in Zhangpu County during the Miocene.