THE LATE MIOCENE BANGMAI FLORA FROM LINCANG COUNTY OF YUNNAN,SOUTHWESTERN CHINA

Abstract

The late Miocene Bangmai Formation flora from Zhongzhai Town in the Lincang Municipality of Yunnan,southwestern China is made up mainly of fossil leaves.It comprises 37 families,59 genera and 71 species(including 37 new species) in total.Amongst them,pteridophyte includes one family one genus and one species(new species).There are two families two genera and two species of gymnosperms.Others are all angiosperms which include 67 species attributing to 55 genera and 34 families.In them there are 32 families 53 genera 65 species(including 35 new species)of dicotyledons and 2 species allocating to 2 genera within 2 families of monocotyledons.In addition to the leaf flora,there is one species of fossil fruit Carpolithes orbitopterus sp.nov.of uncertain affinity.The palaeoflora represents a mixed evergreen and deciduous broad-leaved forest,indicating a slightly humid subtropical climate.The evidence from the fossil plants indicates that the uplifted altitude of the Tibetan Plateau had reached enough height to obstruct the moist Indian ocean atmospheric circulation which resulted in a monsoon climate formation in South and Southeast Asia.A dry and moist alternation of seasonal climate has already existed since then.The Bangmai flora is the late Miocene in age,about later than 11.6 Ma.