Fossil Podocarpus (Podocarpaceae) from the lower Pliocene of Tengchong, Yunnan Province, China and its biogeographic significance

ABSTRACT

Numerous pollens and a few wood fossils with probable affinity to Podocarpus L’Heritier ex Persoon have been discovered from China. However, the leaf fossils of Podocarpus were not well documented. In this study, we describe a new species, Podocarpus pliomacrophyllus sp. nov., from the lower Pliocene of Tengchong, western Yunnan, southwestern China, with detailed cuticular structures. According to gross morphology and cuticular structure of leaves, the present species mostly resembles extant P. macrophyllus (Thunberg) Sweet, which is attributed to the subgenus Foliolatus de Laubenfels. Molecular data support that the genus Podocarpus derived from Gondwana, and the subgenus Foliolatus diverged from the subgenus Podocarpus during the early Miocene. Therefore, the present fossils from Tengchong indicate that the subgenus Foliolatus had spread from India to western Yunnan before the early Pliocene, and then to southeastern China. The Pleistocene glacial events forced Podocarpus to retreat from western Yunnan and the uplifted Hengduan Mountains hindered its reconnection during the subsequent warm interglacials.

KEYWORDS:

• Podocarpus
• Pliocene
• cuticle
• palaeobiogeography
• Yunnan

Acknowledgments

We thank the two reviewers for their constructive suggestions. We also thank Dr. Xiaoli Yan and Dr. Junling Dong from the Key Laboratory of Mineral Resources in western China (Gansu Province), Lanzhou University for their help in obtaining the SEM photos.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Strategic Priority Research Program (B) of the Chinese Academy of Sciences [grant number XDB26000000], the National Natural Science Foundation of China [grant number 31870200], the State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, CAS [grant number 183124], the Fundamental Research Funds for the Central Universities [grant number Lzujbky-2018-51].