Fossil calibration of Magnoliidae, an ancient lineage of angiosperms

Abstract

In order to investigate the diversification of angiosperms, an accurate temporal framework is needed. Molecular dating methods thoroughly calibrated with the fossil record can provide estimates of this evolutionary time scale. Because of their position in the phylogenetic tree of angiosperms, Magnoliidae (10,000 species) are of primary importance for the investigation of the evolutionary history of flowering plants. The rich fossil record of the group, beginning in the Cretaceous, has a global distribution. Among the hundred extinct species of Magnoliidae described, several have been included in phylogenetic analyses alongside extant species, providing reliable calibration points for molecular dating studies. Until now, few fossils have been used as calibration points of Magnoliidae, and detailed justifications of their phylogenetic position and absolute age have been lacking. Here, we review the position and ages for 10 fossils of Magnoliidae, selected because of their previous inclusion in phylogenetic analyses of extant and fossil taxa. This study allows us to propose an updated calibration scheme for dating the evolutionary history of Magnoliidae.