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MA Fujun,WANG Qiujun,DONG Junling,YANG Yi,WANG Wenjia,YAN Defei,SUN Bainian.2015.Buxus Leaves from the Oligocene of Guangxi, China and Their Biogeographical Significance[J].Acta Geologica Sinica(),89(5):1453-1469
Buxus Leaves from the Oligocene of Guangxi, China and Their Biogeographical Signi?cance    Download PDF
MA Fujun  WANG Qiujun  DONG Junling  YANG Yi  WANG Wenjia  YAN Defei  SUN Bainian
This research was financially supported by the National Basic Research Program of China (973 Program) (No. 2012CB822003); the Funds of Key Laboratory of Petroleum Resources, Gansu Province (No. SZDKFJJ20150603), the National Natural Science Foundation of China (Nos. 41172022, 41272026); the Funds of Key Laboratory of Economic Stratigraphy and Palaeogeography, Nanjing Institute of Geology and Palaeontology, CAS (No. Y421140303) and the Fundamental Research Funds for the Central Universities (No. lzujbky-2014-285).
DOI:
Abstract:
      The present paper reports two new species of Buxus from the Oligocene Ningming Formation of Guangxi, South China, on the basis of several compressed fossil leaves. Buxus ningmingensis sp. nov. is characterized by an elliptic to ovate shape; pinnate venation with marginal secondary, long hairs on the adaxial side of the midvein base; and amphistomatic, anomocytic stomata with a prominent outer ring. All of these characteristics suggest a closest af?nity to the living Buxus microphylla subsp. sinica. Another new species identi?ed as Buxus preaustro-yunnanensis sp. nov. is characterized by the diagnostic formation of its admedially branched tertiaries, the trunks of which are often strongly thickened by sclereides. This species is most similar to the extant Buxus austro-yunnanensis. The co-occurrence of Buxus ningmingensis sp. nov. and Buxus preaustro-yunnanensis sp. nov. suggests that these two Buxus lived during the Oligocene under a warm, tropical to subtropical climate, similar to the current climate of Ningming. Our ?ndings provide the earliest fossil evidence of Buxus leaves with detailed illustrations of leaf architectural and cuticular features. The occurrence of these two species indicates that Buxus began to diversify in Guangxi no later than the Oligocene.
Key words:Buxus, diversification, paleoclimate, Oligocene, Guangxi
Buxus Leaves from the Oligocene of Guangxi, China and Their Biogeographical Significance    Download Fulltext
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