Abstract Detail



Paleobotany

Oskolski, Alexei [1], Stepanova , Anna [2], Huang, Luliang [3], Jin, Jianhua [4].

Araucarioid fossil wood from the late Oligocene - early Miocene of Hainan Island: the most ancient evidence of the genus Agathis in eastern Asia.

Although many fossil and molecular data suggest migrations from Malesia and Asia to Australia appear to dominate floristic exchange between Australian and Asian rainforests, evidence is emerging  that demonstrate dispersal of plant groups from Australia to Asia. In this paper, a new species Agathis ledongensis sp. nov. is described on the basis of silicified wood from the late Oligocene – early Miocene of the Qiutangling Formation in Ledong, Hainan Island, South China. It is the first fossil record of Agathis in the Northern Hemisphere, and the only known fossil evidence of its dispersal outside of Gondwana. The close affinity of the fossil wood from Ledong with the genus Agathis was confirmed by comparing quantitative traits in 31 wood samples of 20 species representing all three extant genera of the Araucariaceae. The percentage of tracheids with uniseriate pitting on radial walls is shown as an additional diagnostic trait for separating Agathis and Wollemia from Araucaria. The wood of Agathis ledongensis provides evidence for the dispersal of this important plant group from Australia, or another Gondwanan terrane, to eastern Asia based on reliable fossil data. It records the occurrence of this genus in Hainan Island by the early Miocene, i.e. at the beginning of the formation of the island chains between Australia and the South-East Asia and thus the provision of a land migration route. As the land routes between these continents were restricted at that time, the migration of Agathis to Malesia and Asia was presumably facilitated by long-distance dispersal of its winged seeds by wind.   This study was supported by the National Natural Science Foundation of China (NSFC, Grant Nos. 41572011, 41820104002), the joint Project of NSFC and the Russian Foundation for Basic Research (Grant Nos. 41811530082, 18-55-53015), the NRF of South Africa (Incentive Grant No. 109531), the State Key Laboratory of Palaeobiology and Stratigraphy (Nanjing Institute of Geology and Palaeontology, CAS) (No. 173101), and the Guangdong Provincial Key Laboratory of Plant Resources (No. PlantKF04), and by the Komarov Botanical Institute (institutional research Project No. AAAA-A18-118030690081-1).


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1 - University of Johannesburg, Botany and Plant Biotechnology, PO Box 524 Auckland Park, Johannesburg, Gauteng, 2006, South Africa
2 - Komarov Botanical Institute, Prof. Popov 2 , St.Petersburg, 197376, Russia
3 - Sun Yat-sen University, School Of Life Sciences, 135 Xingangxi Road, Guangzhou, 44, 510275, China
4 - School Of Life Sciences, 135 Xingangxi Road, Guangzhou, Guangdong, 44, 510275, China

Keywords:
Agathis
Araucariaceae
Oligocene
Miocene
Fossil Wood
Biogeography
South China
Hainan
wood anatomy.

Presentation Type: Oral Paper
Session: PAL4, Paleobotany II: Cenozoic Paleobotany
Location: Virtual/Virtual
Date: Tuesday, July 28th, 2020
Time: 1:45 PM
Number: PAL4006
Abstract ID:372
Candidate for Awards:None


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