Two Eocene fossil fruits from the Changchang Basin of Hainan Island,China

Two types of fossil fruit, one belonging to Palaeocarya sp. (Juglandaceae) and the other to Acer cf. A. miofranchetii Hu et Chaney (Aceraceae), are found in the Eocene coal-bearing series from the Changchang Basin of Hainan Island, China. This is the first fossil record of Palaeocarya and Acer in a tropical area of China. These fossils provide evidence for an investigation of the phytogeographic history of these two genera. Since their extant relative genera are distributed mostly in northern temperate or tropical–subtropical mountainous regions, I propose that the Changchang Basin of Hainan Island was close to a mountainous region in the Eocene; the plants bearing these fruits were growing at a mid-high altitude with a relatively cool climate, and the fruits were not preserved in situ but transported to the fossil site. The characters of other associated fossil plants and palynological data also support this hypothesis.