Dispersal and delimitation: Phylogenomics of Connaraceae prompts revised generic delimitation in Cnestideae and reveals global biogeographic patterns

Abstract The tempo and mode of assembly of the world's most diverse, tropical floras remain poorly known. Evolutionary relationships within pantropical plant clades such as Connaraceae (Oxalidales, ca. 220 species) offer an opportunity to address this issue. However, the family has a history of conflicting generic treatments, resulting in incongruent generic concepts across continents. Here, we present a greatly expanded, complete genus‐level phylogeny for the Connaraceae based on phylogenomic data from herbarium specimens using the Angiosperms353 bait kit. We use it in combination with an extensive study of herbarium material to formally revise generic delimitations and to infer the timing of major biogeographic movements, addressing in particular whether its pantropical distribution was achieved via Gondwanan vicariance, boreotropical dispersal, or more recent long‐distance dispersal. Major clades of the well‐supported phylogeny confirm recent revisions at the tribe and subfamily levels and are supported by flower and fruit characters. Within Cnestideae, containing around half of the species of Connaraceae, Rourea is polyphyletic in its most recent circumscription (that united nine earlier recognised genera). It falls into five well‐supported, morphologically coherent clades, interdigitated with other genera, prompting us to newly accept eight genera in Cnestideae. A formal taxonomy including keys to genera, descriptions, and species‐checklists including new names and combinations is provided. Bayesian dating and biogeographic analysis reveal a surprisingly old split of Connaraceae from Oxalidaceae (ca. 82 Ma) and an African origin of Connaraceae. Jump‐dispersal models are statistically preferred, suggesting long‐distance dispersal out of Africa. However, scenarios of a dispersal out of Africa via the Northern Hemisphere in the Eocene, congruent with a boreotropical scenario, cannot be ruled out. Overall, our updated taxonomy and nomenclature aid identification and simplify comparisons between biogeographical regions by maintaining consistency across them. This consistency facilitates research from local to global scales, shedding new light on the assembly of the world's tropical floras.