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Eperua is a genus of Neotropical trees that forms a major component of tropical lowland forests in Amazonia, especially in the Guiana Shield and on white-sand forests. One species occurs in the Cerrado-Caatinga ecotone, and the genus also inhabits riverine and terra firme forests. Species in Eperua exhibit one of two drastically different floral architectures and inflorescence types, each associated with distinct pollinators. Prior phylogenetic studies of Eperua have revealed an unstructured topology concerning floral architectures and inflorescence types. In addition, no investigation has been conducted on how the evolution of these traits and habitat preferences influenced the dispersal and diversification of Eperua. Using target capture sequencing, we inferred the most comprehensive phylogeny for Eperua to date, sampling all 19 known species, five for the first time. We used coalescence, concatenation, and network methods to infer the Eperua phylogeny and investigate sources of incongruence impacting resolution and support. We reconstructed the biogeographic history and ancestral states for the flower architecture, inflorescence type, and habitat preference. Our phylogenomic analyses successfully resolved relationships within Eperua, attributing conflicts between the species tree and concatenated tree to gene tree discordance linked to reticulation events. Biogeographical analyses indicate that Eperua originated and initially diversified in the white-sand forests of the Guiana Shield. A subsequent adaptation to riverine and terra firme forests enabled Eperua to expand into new habitats and regions. Still, its historical preference for white-sand forests probably accounts for its absence in the southern and western parts of Amazonia. Ancestral geographic areas and corolla morphotype reconstructions suggest that speciation in Eperua has occurred in sympatry, likely driven by pollinator shifts mediated by drastic changes in floral architecture., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Premise: The Amazonian hyperdominant genus Eperua (Fabaceae) currently holds 20 described species and has two strongly different inflorescence and flower types, with corresponding different pollination syndrome. The evolution of these vastly different inflorescence types within this genus was unknown and the main topic in this study., Methods: We constructed a molecular phylogeny, based on the full nuclear ribosomal DNA and partial plastome, using Bayesian inference and maximum likelihood methods, to test whether the genus is monophyletic, whether all species are monophyletic and if the shift from bat to bee pollination (or vice versa) occurred once in this genus., Results: All but two species are well supported by the nuclear ribosomal phylogeny. The plastome phylogeny, however, shows a strong geographic signal suggesting strong local hybridization or chloroplast capture, rendering chloroplast barcodes meaningless in this genus., Conclusions: With our data, we cannot fully resolve the backbone of the tree to clarify sister genera relationships and confirm monophyly of the genus Eperua. Within the genus, the shift from bat to bee and bee to bat pollination has occurred several times but, with the bee to bat not always leading to a pendant inflorescence., (© 2023 The Authors. American Journal of Botany published by Wiley Periodicals LLC on behalf of Botanical Society of America.)