New discovery of Mahonia fossils from the Pliocene of Yunnan, China, and its biogeographical significance

Mahonia Nuttall (Berberidaceae Jussieu) is an East Asian-North American disjunct evergreen genus. There are many fossil records of Mahonia from the Eocene to Pleistocene in North America and Europe, but only a few reliable fossils have been reported from East Asia. Compressed fossil leaflets, described here as Mahonia mangbangensis sp. nov. and Mahonia cf. oiwakensis, were collected from the Pliocene Mangbang Formation in Tengchong County, Yunnan Province, southwest China. These new fossil specimens show the same leaf architectural characteristics as those belonging to the Group Orientales of Mahonia, and represent the youngest occurrence of the genus in East Asia. This new fossil discovery extends the stratigraphic range of Mahonia in East Asia and provides new insights into the potential differentiation and migration routes of the Group Orientales in China. Mahonia probably differentiated during the Pliocene in western Yunnan, representing part of the diversification history of this genus in East Asia.