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.2013.[J].Acta Geologica Sinica(),87(3):690-706
A New Material of Lindera (Lauraceae) of the Late Pliocene from Tengchong, Yunnan and the Genus' Biogeography Significance    Download PDF
DAO Kequn  CHEN Junlin  JIN Peihong  DONG Chong  YANG Yi  XU Xiaohui  WU Jingyu  XIE Sanping  LIN Zhicheng  SUN Bainian
1 School of Earth Sciences and Key Laboratory of Mineral Resources in Western China, (Gansu Province)
, Lanzhou University, Lanzhou 730000, China 2 School of Petroleum Engineering, Chongqing University of Science & Technology, Chongqing 401331, China
This work was conducted under the National Basic Research Program of China (973: No. 2012CB822000); the National Natural Science Foundation of China (Nos. 41172022 and 41172021); the Fundamental Research Funds for the Central Universities (No. lzujbky-2012-127).
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Abstract:
      Lindera is a large genus of graceful, pleasantly scented and common native trees and shrubs of southern China and neighboring regions of SE Asia. There is a well-documented Cenozoic fossil record not only in these regions but also from elsewhere. A new fossil leaf record has been found in diatomite beds from the Upper Pliocene Mangbang Formation of Tuantian, Tengchong County, Yunnan. The leaves are identified and assigned to Lindera acuminatissima K. Q. Dao et B. N. Sun sp. nov., by comparing their leaf architecture and epidermal characteristics with those of 51 extant Lauraceae species and with 15 known fossil Lindera taxa. The specimens have well-preserved cuticles, with typical leaf architecture and epidermal characteristics of the Lauraceae, including entire leaf margin, intramarginal veins, basal ternate acrodromous primary veins, one-cell trichome base, paracytic stomatal apparatus, sunken guard cells, subsidiary hardly staining cells and presence of oil cells. These characteristics are consistent with Lindera sect. Daphnidium but are different from reported fossil and extant species of Lindera. The cuticles of Lindera are fragile and delicate with only three Lindera fossils reported based on this tissue. In terms of paleobiogeography, the fossil record indicates that Lindera is distributed in high- to mid-latitude regions of the Late Cretaceous to Paleocene northern hemisphere. Coincidentally, the records of Lindera located on both sides of the Bering Land Bridge possibly support the hypothesis that ancient plants extended via transcontinental exchanges through the Bering Corridor. In the Eocene, ancient Lindera spread to Europe through the Northern Degeer Route and the Southern Thulian Route. At the same time, ancient Lindera spread into Central Asia. Climatic changes and tectonization since the Neogene prevented the propagation of Lindera throughout Asia, North America and Europe, and hence the distribution areas have just regressed to the low-latitude regions in Asia and North America. From the Paleogene to the Neogene, Lindera has changed its distribution by surviving extreme climate changes. Quaternary glaciations ultimately led to Lindera becoming extinct in Europe. The new record from Tengchong, Yunnan, with its lower latitude located in tropical and subtropical regions, indicates that Lindera has lived in those regions since the late Pliocene.
Key words:paleobotany, fossil leaves, cuticle, biogeography, Piacenzian, Yunnan province
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