Alseodaphne changchangensis sp. nov. (Lauraceae), with a perfectly preserved fossil leaf, was found in the Eocene Changchang Formation from the Changchang Basin of Hainan Island, China. This represents the earliest occurrence at the lowest latitude for the genus Alseodaphne, and offers important fossil evidence for further investigation of the origin and evolution of this genus and the paleo-climate of Hainan Island in the Eocene. Based on leaf morphology and cuticle characteristics, our fossil specimen is closest to the living species A. hainanensis Merrill, which is distributed mainly in tropical lowland rain forests, tropical montane rain forests, and subtropical montane evergreen broad-leafed forests on Hainan Island, and also found on the Wanshan Islands of Zhuhai of Guangdong Province and in northern parts of Vietnam. In the above areas, the climate factors are similar, i.e., the mean annual temperature is 20-22.6℃, the mean annual range of temperature 12-12.6℃ and the mean annual precipitation 1784-2500 mm. Based on the nearest living species analysis, we conclude that the climate of the Changchang Basin on Hainan Island during the Eocene was close to that of the distribution areas of the living A. hainanensis.
