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

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.

Automated summary

A new species, Podocarpus pliomacrophyllus sp. nov., has been described from lower Pliocene deposits in western Yunnan, China, showing gross morphology and cuticular structure similar to extant P. macrophyllus. Molecular data suggests that the genus Podocarpus originated from Gondwana, with the subgenus Foliolatus diverging from the subgenus Podocarpus during the early Miocene. Fossils from Tengchong indicate the subgenus Foliolatus spread from India to western Yunnan before the early Pliocene, and subsequently to southeastern China.