The interplay of biogeographic history, floral morphology, and climatic niche in Palicourea (Rubiaceae), a species-rich Neotropical plant radiation

Ana Maria Bedoya , Charlotte Taylor, Aislinn Mumford, Laymon Ball, Laura Lagomarsino

Investigating how biotic and abiotic factors interact to shape species evolution is critical to understanding biodiversity patterns in the Neotropics, a region where an interplay of processes promoting diversification shaped the assembly of the world’s richest flora. Using Palicourea, a species-rich and ecologically and morphologically diverse group of Neotropical plants in the coffee family, we aimed to identify patterns resulting from the interplay of biogeographic history, floral morphology, and climatic niche evolution. We inferred the most completely sampled multi-locus phylogeny of Palicourea to date, modeled species historical ranges, detected shifts in climatic and elevational preferences, and reconstructed the evolution of inflorescence morphology. Lowland Eastern-Northeastern South America and the montane Andean region are centers of species richness. Evolutionary dynamics in the two regions differ and result from a tradeoff between climatic niche disparity and lability of characters related to pollination. The latter is not related to climatic filtering of reliable pollinators across elevation. The interaction of biotic and abiotic factors has led to a continental radiation of plants that form an important ecological cornerstone of the Neotropics. Decades of botanical research in Palicourea and newly generated genomic data helped reveal patterns and processes shaping niche and range shifts in this diverse group.