Nuclear phylogenomics and revised tribal classification of Achariaceae, with a redefinition of <i>Oncoba</i> (Salicaceae)

Abstract A genus-level phylogenetic analysis of Achariaceae is presented, including representatives of all genera of the family and several taxa putatively placed there. We apply a target sequence capture approach using the Angiosperms353 probes to obtain a comprehensive set of genes for the analysis in an attempt to provide improved resolution of their relationships. The results show that the family includes five main clades that largely (but not completely) correspond to currently recognized tribes: (I) Pangieae plus Acharieae, (II) Chlorocarpa and Hydnocarpus, (III) Phyllobotryeae, (IV) Erythrospermeae plus Prockiopsis, and (V) a clade of African taxa currently placed within Lindackerieae. Based on the topologies presented, five tribes are proposed for the family: Acharieae (including genera previously assigned to Pangieae), Hydnocarpeae (a new tribe to accommodate Chlorocarpa and Hydnocarpus), Phyllobotryeae, Erythrospermeae (including Prockiopsis, formerly in Lindackerieae), and Lindackerieae, the last two tribes being maintained out of practicality, pending further review. Generic circumscriptions are challenged. Our results indicate that Caloncoba, Camptostylus and Xylotheca comprise a single genus. Lindackeria is polyphyletic; African and neotropical species are not closely related, and those from Africa may instead comprise a separate genus along with members of Buchnerodendron and Peterodendron. As-yet unidentified specimens used in our analysis may represent new taxa. The position of the recently described genus Salpingifera remains uncertain. We present strong evidence for the re-establishment of Oncoba as the pre-1995 Afro-Arabian genus comprising O. brachyanthera, O. routledgei and O. spinosa.