Fruits and leaves of Dipterocarpus from the Miocene of Zhangpu, Fujian, and its geological significance

Dipterocarpus (Dipterocarpaceae), an important component of tropical rainforests, has significant paleoclimate implications. Here some well-preserved leaves and winged fruit fossils of Dipterocarpus from the Miocene of Fotan in Fujian, southeast China, and their cuticle structures are described in detail. The fruit fossils are identified with the previously described as the fossil Dipterocarpus zhengae. Based on detailed gross morphology and cuticle micromorphology of leaves and cluster analysis, the leaf fossils can be attributed to the genus Dipterocarpus and described as Dipterocapus fotanensis sp. nov. The occurrence of the winged fruit and leaves of Dipterocarpus indicates a moist and warm climate during the Middle Miocene in Fujian. Two hypotheses about the origin of Dipterocarpaceae are reviewed on the basis of the comparison of the distribution of modern species and fossil records. One of the two suggests that Gondwana was the cradle of Dipterocarpaceae and is more reasonable than the other one that regards Southeast Asia as the origin of this family. All known Dipterocarpus fossils are collected and labeled on a map, which visually suggests that Dipterocarpus migrated eastwards to Fujian, China, during the Middle Miocene.