The Grevilleoideae (Proteaceae) are distributed widely throughout former Gondwanan landmasses (South America, Australia, New Zealand, New Caledonia, Africa, and Madagascar) and have even crossed Wallace’s Line into tropical Asia. Fossil evidence suggests the group originated in mesic biomes but present-day hotspots of mega-diversity are found in dry temperate and Mediterranean ecosystems. This group is a thus prime candidate for understanding the role of historical environmental change on regional biodiversity patterns, but to date no species-level phylogeny has been available to analyze diversification patterns. We generated a species-level phylogenomic dataset for nearly all members of the subfamily Grevilleoidea (>800 species), and produced a set of alternative phylogenetic hypotheses, accounting for discordant gene-tree histories. We compiled a large fossil dataset and applied alternative calibration strategies for divergence dating, capturing uncertainty in fossil placements. This pipeline allows us to test the role of historical climate change and plate tectonics on the biogeography and diversity of Grevilleoideae, accounting for many sources of uncertainty in phylogenetic inference. We used paleoenvironmental reconstruction of biomes around the globe to constrain biogeographic estimation models and inferred the biogeographic origin of the clade, and vicariance and dispersal events between major biomes throughout the southern hemisphere and Asia. Our results highlight the role of paleoenvironmental dynamics on the evolution of a megadiverse plant group.
Phylogenomics of a hyper-diverse plant clade (Grevilleoidea; Proteaceae) reveals the paleoenvironmental origins of a fractured distribution