A mega-phylogeny of the Annonaceae: taxonomic placement of five enigmatic genera and support for a new tribe, Phoenicantheae

The Annonaceae, the largest family in the early-divergent order Magnoliales, comprises 107 genera and c. 2,400 species. Previous molecular phylogenetic studies targeting different taxa have generated large quantities of partially overlapping DNA sequence data for many species, although a large-scale phylogeny based on the maximum number of representatives has never been reconstructed. We use a supermatrix of eight chloroplast markers (rbcL, matK, ndhF, psbA-trnH, trnL-F, atpB-rbcL, trnS-G and ycf1) to reconstruct the most comprehensive tree to date, including 705 species (29%) from 105 genera (98%). This provides novel insights into the relationships of five enigmatic genera (Bocagea, Boutiquea, Cardiopetalum, Duckeanthus and Phoenicanthus). Fifteen main clades are retrieved in subfamilies Annonoideae and Malmeoideae collectively, 14 of which correspond with currently recognised tribes. Phoenicanthus cannot be accommodated in any existing tribe, however: it is retrieved as sister to a clade comprising the tribes Dendrokingstonieae, Monocarpieae and Miliuseae, and we therefore validate a new tribe, Phoenicantheae. Our results provide strong support for many previously recognised groups, but also indicate non-monophyly of several genera (Desmopsis, Friesodielsia, Klarobelia, Oxandra, Piptostigma and Stenanona). The relationships of these non-monophyletic genera—and two other genera (Froesiodendron and Melodorum) not yet sampled—are discussed, with recommendations for future research.