Phylogeny and systematics of African Melastomateae (Melastomataceae)

Abstract

Melastomateae are the most species-rich (185 spp./13 gen.) and morphologically diverse tribe within the African Melastomataceae. In this study we present the first in-depth phylogenetic analysis of African Melastomateae using sequences generated from one nuclear (nrITS) and two plastid spacers (accD-psaI, psbK-psbL) sampling 183 accessions representing 75 African, 10 Madagascan and 7 Asian species and a broad outgroup sampling. We infer phylogenetic relationships using maximum likelihood, maximum parsimony and Bayesian approaches and propose a revised generic classification of African Melastomateae based on our molecular trees in combination with a careful reassessment of morphological variation. Our phylogenetic analyses support the monophyly of Old World Melastomateae except Dinophora which clearly falls outside Melastomateae. Asian and Madagascan endemic genera of Melastomateae are nested among the African genera. Of the African genera only two monophyletic groups, Dichaetanthera and Tristemma, are recovered in addition to the monospecific Pseudosbeckia lineage, while Antherotoma, Dissotis and Heterotis as currently circumscribed are polyphyletic. However, the subgenera and sections of these genera are mostly recovered as morphologically distinct and molecularly well-supported clades. Isomorphism versus dimorphism of the stamens is found to be an unreliable character when delimiting genera in Melastomateae. We propose the reinstatement of Argyrella and Dupineta, a new status at generic rank for Dissotis subg. Dissotidendron, a broadened circumscription of Guyonia (to include the species previously placed in Heterotis sect. Cyclostemma), and description of a new, monospecific genus Anaheterotis for the Heterotis pobeguinii lineage. Heterotis is maintained at generic rank but with a narrower circumscription in comparison to earlier treatments. We accommodate the rare Osbeckia porteresii lineage from Mt. Nimba (Guinea) within an expanded Melastomastrum. To complete our generic realignment, a total of 42 new combinations are effected at the species level and below, and a key is provided for the 12 genera presently recognised in African Melastomateae. Denser taxonomic sampling and sequencing of more loci will be needed to resolve relationships within the large clade of Dissotis s.str. and allies (including Antherotoma as well as three West African species erroneously placed in the otherwise Asian Osbeckia).

Systematics and relationships of Tryssophyton (Melastomataceae), with a second species from the Pakaraima Mountains of Guyana

“…However, if this topology holds with increased sampling of taxa and genetic loci, it would suggest that the mostly Asian Sonerileae-Dissochaeteae complex originated in South America and then dispersed to Africa and later to Asia where it diversified. A similar pattern has been found to the Melastomateae (Michelangeli et al 2013, Veranso-Libalah et al 2017. Recent phylogenetic studies of the Sonerileae-Dissochaeteae complex have already shown that most genera are not monophyletic and the group needs considerable further study (Zeng et al 2016, Zhou et al 2019a, 2019b.…”

Novitates Gabonenses 88: additions to the flora of Gabon and new records of little-known species

“…Notes -This uncommon species was first described as Heterotis arenaria by Jacques-Félix (1988) from a single specimen collected in the extreme south of Gabon, and later as H. obamae by Lejoly & Lisowski (1999) from Equatorial Guinea. Parmentier & Geerinck (2003) recognised the two species as identical, an observation overlooked by subsequent authors (Sosef et al 2006, Harris et al 2012, Veranso-Libalah et al 2017. The species is now recorded from six localities along the coast of southern Gabon, and two in Equatorial Guinea.…”

Exploring the generic delimitation of Phyllagathis and Bredia (Melastomataceae): A combined nuclear and chloroplast DNA analysis

“…Molecular phylogenetic analyses have proven useful in resolving relationships at the generic level in Melastomataceae (Ionta et al, 2007;Reginato et al, 2010;Stone & Andreasen, 2010;Stone, 2014;Kriebel, 2016;Reginato & Michelangeli, 2016;Veranso-Libalah et al, 2017). Several phylogenetic studies had included Phyllagathis or Phyllagathis and Bredia in their analyses (Clausing et al, 2000;Clausing & Renner, 2001b;Fritsch et al, 2004;Zeng et al, 2016aZeng et al, , 2016bZhou et al, 2018).…”