Study On Three Angiosperm Fossil Fruits From The Miocene Of Lincang,Yunnan Province,China

Yunnan Province is the richest biodiversity region in China,which has preserved a large number of endemic genera in addition to plenty of ancient relicted plants,because of the intense uplift of the Tibetan Plateau,the formation of the monsoonal circulation system,the influence of Quaternary glaciers and changes in the climate and environment since the Cenozoic.Yunnan has well-developed Cenozoic strata,which is an important part of the Cenozoic flora of China.The numerous intermountain basins of Lincang in the Neogene preserve rich plant fossils,which are favourable sites for researching plant diversity,flora evolution,angiosperm migration routes as well as the evolution of monsoon formation,and provide palaeobotanical evidence for the synergistic evolution of the paleoclimate,paleoenvironment and organisms of Lincang in Neogene.In this paper,the morphology about fossil fruits of the Bangmai Formation in Miocene from Bangmai flora in Lincang,Yunnan are studied.Based on the comparative analysis with related living plants and fossil records,three genera and three species are identified,including one new species each of Craigia,Fallopia,and one known species of Ventilago.The palaeophytogeography of Craigia,Fallopia and Ventilago is discussed in the light of the global fossil record,extant distribution and molecular biology.It is highly likely that Craigia originated from Sakhalin of Northeast Asia in the Paleocene.Craigia has spread to North America and East Asia during the Eocene,reached continental Europe during the Oligocene,and reached the Lincang of Yunnan by the Miocene,thus forming the modern distribution pattern of Craigia.Fallopia probably originated in southwestern China between Oligocene and Miocene,and thereafter spread eastward and northward to South China and North China,the Korean peninsula and Japan.On the other hand,Fallopia spread westwards to Europe and probably to America via Greenland.Ventilago probably originated in South Asia no later than Oligocene;after its origin in South Asia,Ventilago probably spread eastward to Southeast Asia,East Asia,and Oceania,spread westward to Africa,and possibly spread along Europe-Greenland to the Americas.The paleoenvironment of Lincang was recovered by means of Climate Analysis of Endemic Species and Coexistence Approach,and the differences from the present environment and possible causes were analysed.The paleoclimate in Late Miocene of Lincang was reconstructed quantitatively according to the endemic species and NLRs: the MAT was 16.4-21.0°C,the CMT was 11.5-14.2°C,the WMT was 20.3-25.6°C,and the MAP was1751.0-1863.3 mm.This data is higher than the modern data of Lincang,which indicates that the climate in Miocene of Lincang was warmer and more humid than that of today.It may be related to global cooling as well as the formation and development of East Asian monsoon circulation in the end of Miocene.Based on the coexistence approach of the elevations from the NLRs about the fossil species,the paleoelevation of Lincang in Late Miocene was 883-1233 m,which is 447-797 m lower than the present elevation of 1680 m in Lincang,indicating that Lincang may have uplifted447-797 m to reach the present elevation after Late Miocene.