Molecular Phylogenetic Support for the Taxonomic Merger of Fitzalania and Meiogyne (Annonaceae): New Nomenclatural Combinations Under the Conserved Name Meiogyne

Abstract—

Meiogyne (Annonaceae) currently comprises 15 species of trees and shrubs, distributed in India, Southeast Asia, Australasia, Micronesia and Polynesia. Previous molecular phylogenetic studies have shown that the Australian endemic genus Fitzalania (consisting of only two species) is nested within Meiogyne, and preliminary morphological data have indicated that several south Pacific Polyalthia species may be misclassified and also associated with Meiogyne. We use maximum parsimony, maximum likelihood and Bayesian analyses based on seven chloroplast regions (matK, ndhF, ndhF-rpl32, rbcL, rpl32-trnL, trnL-F and ycf1) to reconstruct the most comprehensive phylogeny of Meiogyne available to date, inclusive of 13 Meiogyne species, the two Fitzalania species, as well as four Polyalthia species from Fiji and Tonga. The results show that Fitzalania and the four Polyalthia species are nested within Meiogyne, and that two species, M. cylindrocarpa and M. stenopetala, are not natural as currently defined. Meiogyne cylindrocarpa subsp. trichocarpa and M. stenopetala subsp. insularis are not conspecific with their respective autonymic subspecies and are morphologically distinct. Based on the plastid marker phylogeny, and corroborated by morphological observations, both subspecies are elevated to species rank, and the four Polyalthia species and the two Fitzalania species are transferred to Meiogyne, thereby increasing the number of species in the genus to 24.