Phylogenomic inference of the African tribe Monodoreae (Annonaceae) and taxonomic revision of Dennettia, Uvariodendron and Uvariopsis

Abstract

Monodoreae (Annonaceae) is a tribe composed of 11 genera and 90 species restricted to the tropical African rain forests. All the genera are taxonomically well circumscribed except the species rich genera Uvariodendron and Uvariopsis which lack a recent taxonomic revision. Here, we used a robust phylogenomic approach, including all the 90 currently accepted species, with several specimens per species, and based on more than 300 Annonaceae-specific nuclear genes, to infer the phylogenetic tree of the Monodoreae and test the limits between the genera and species. We recover all the genera as monophyletic, except the genus Uvariopsis for which the species Uvariopsis tripetala falls outside this clade. We thus reinstate the monotypic genus Dennettia for its single species Dennettia tripetala. We also erect a new tribe, Ophrypetaleae trib. nov., to accommodate the genera Ophrypetalum and Sanrafaelia, as we recover them excluded from the Monodoreae tribe with good support. Below the genus level, the genera Isolona, Monodora, Uvariastrum, Uvariodendron and Uvariopsis show weakly supported nodes and phylogenetic conflicts, suggesting that population level processes of evolution might occur in these clades. Our results also support, at the molecular level, the description of several new species of Uvariodendron and Uvariopsis, as well as several new synonymies. Finally, we present a taxonomic revision of the genera Dennettia, Uvariodendron and Uvariopsis, which contain one, 18 and 17 species respectively. We provide a key to the 11 genera of the Monodoraeae and describe four new species to science: Uvariodendron kimbozaense Dagallier & Couvreur, sp. nov., Uvariodendron mossambicense Robson ex Dagallier & Couvreur, sp. nov., Uvariodendron pilosicarpum Dagallier & Couvreur, sp. nov. and Uvariopsis oligocarpa Dagallier & Couvreur, sp. nov., and provide provisional descriptions of three putatively new species. We also present lectotypifications and nomenclatural changes implying synonymies and new combinations (Uvariodendron citriodorum (Le Thomas) Dagallier & Couvreur, comb. et stat. nov., Uvariodendron fuscum var. magnificum (Verdc.) Dagallier & Couvreur, comb. et stat. nov., Uvariopsis congensis var. angustifolia Dagallier & Couvreur, var. nov., Uvariopsis guineensis var. globiflora (Keay) Dagallier & Couvreur, comb. et stat. nov., and Uvariopsis solheidii var. letestui (Pellegr.) Dagallier & Couvreur, comb. et stat. nov.).