TAXONOMY AND PHYLOGENOMICS OF CHRYSOBALANACEAE

The Chrysobalanaceae is a pantropical woody plant family of 546 species and 27 accepted genera. Its centre of diversity is the Amazon where it is among the most numerically important in both number of species and individual trees in forest tree inventories. The family has been extensively studied at the alpha-taxonomic level, culminating in a comprehensive account of all taxa; however, molecular phylogenetics revealed the non-monophyly of several genera, casting doubts as to the relationships suggested by the last classification, published in 2003. The first molecular phylogenetic analyses used single loci (Sanger sequences) and clades were weakly supported, hindering interpretation of results. Phylogenomics, using complete genomes, provided better results with more robust support for clades and uncovered novel relationships among genera. Here I outline the taxonomic history of the family and trace the journey from major taxonomic circumscriptions based on morphology and discuss key findings and contributions from my molecular phylogenetic research starting from 2006, and how results both confirm and contradict the traditional taxonomy. Our analyses retrieve six clades, among them the earliest diverging clade composed of Bafodeya from West Africa and Kostermanthus from Australasia, and a species-rich clade, the Neotropical clade, of ca. 400 species in 11 neotropical genera that includes the three largest, Couepia, Hirtella and Licania, previously considered distantly related. This clade also has a single West African monospecific genus, Afrolicania. Results confirm that genera previously described under Parinari are distinct and more distantly related than previously thought. The most recent molecular phylogenetic studies completed in 2020, suggest the family diversified in the EoceneOligocene transition, ca. 38.9 Mya and support a palaeotropical origin, most probably in Africa, and shows that rates of diversification were highest in the Neotropics. The relationships uncovered in my recent molecular studies have provided a monophyletic classification of genera that is essential for producing accurate conservation assessments and supports hypotheses on the role of species diversification within a historic biogeographical context