Fagaceous foliage from the latest Cretaceous of the Koryak Upland (northeastern Russia) and its implications for the evolutionary history of Fagaceae

•Fagaceous leaves from the Maastrichtian deposits are described.•Fagopsiphyllum groenlandicum leaf morphology is analyzed.•Fagopsiphyllum leaves are compared with those of the other Fagaceae.

The first record of the genus Fagopsiphyllum (Fagaceae) from the Maastrichtian Kakanaut Formation of the Koryak Upland, northeastern Russia, is described and compared to other recorded of Fagaceae and fagaceous-like leaves from the Cretaceous and Paleogene of the Northern Pacific Region. The distribution and morphological variability of Fagopsiphyllum groenlandicum are investigated. Fagopsiphyllum groenlandicum leaves resemble mainly the foliage of the extinct genera Fagopsis and Barykovia. New finding of Fagopsiphyllum groenlandicum extends the stratigraphic range of this taxon and contributes to the Cretaceous morphological diversity of extinct leaf forms assigned to Fagaceae. Taxonomic position of Fagopsiphyllum is discussed.