The evolution and global migration of the Aceraceae

This article shows how a large palaeontological database (the Plant Fossil Record version 2.2, available on the Internet) can be used to draw evolutionary and migratory pathways. 2946 published records of the family Aceraceae have been found as leaf, fruit and seed, wood or pollen fossils, and their geographical and stratigraphical distributions are presented here in different graphical forms. Manipulation and analysis of the data have produced palaeo-geographic maps of these distributions, curves of the number of records in five global regions over the last 100 million years, and cladograms of taxa and their geography. The results give objective evidence which shows that early members of the family became well established on upland slopes of the north Pacific rim during the Palaeogene. Some of these early species migrated eastwards across Greenland to Europe before the North Atlantic opened to the Arctic. Later and larger migrations started in the Oligocene, from Asia westwards to central Europe, bringing a diversification in species both there and in the regions of origin.