Molecular phylogeny and taxonomic synopsis of the angraecoid genus Ypsilopus (Orchidaceae, Vandeae)

Abstract

Previous phylogenetic analyses focused on angraecoid orchids suggested that the genus Ypsilopus was paraphyletic and that some species of Tridactyle and Rangaeris belong to a clade that included Ypsilopus. These studies, based on three to four genes, sampled few taxa in each genus, and did not include the type of Rangaeris, nor did they take morphological variation into account. To delineate Ypsilopus more precisely, we reconstructed phylogenetic relationships of the genus and seven other closely related genera by analysing sequence variation at the nuclear ribosomal internal transcribed spacer (ITS‐1) and at five plastid markers (matK, rps16, trnC‐petN intergenic spacer, trnL‐trnF intergenic spacer, ycf1), from 42 specimens representing 36 taxa. Trees based on maximum likelihood and Bayesian inference confirm that two species of Tridactyle are nested with three Ypsilopus species, including the type of the latter, and two species of Rangaeris are grouped with this clade. Moreover, we examined morphological variation among all species belonging to these three genera, highlighting morphological features that characterize Ypsilopus, and we used these data to assign the two species of Tridactyle included in the molecular analyses, three other species of Tridactyle not included in the molecular analyses and two species of Rangaeris to Ypsilopus. New combinations for Tridactyle citrina, T. furcistipes, T. sarcodantha, T. tanneri, T. tricuspis, Rangaeris amaniensis and R. schliebenii in Ypsilopus are thus proposed, and one new section (i.e., Ypsilopus sect. Barombiella) is described. Keys to the species of Ypsilopus and closely related genera are provided, along with a table of characters that can be used to differentiate these species.

An Elegy to Rangaeris, Including a Description of Two New Genera in the Cyrtorchis–Tridactyle Clade (Orchidaceae, Angraecinae)

“…The 63 newly obtained sequences were combined with 71 previously published sequences (Carlsward et al, 2006;Simo-Droissart et al, 2018a;D'haijère et al, 2019) retrieved from GenBank (,https://www.ncbi.nlm.nih.gov/ genbank/.). Voucher specimens and respective metadata are provided in Appendix 1.…”

“…Within the largest subfamily, Epidendroideae, and more specifically within the tribe Vandeae, several recent studies have focused on the systematics of subtribe Angraecinae in Madagascar and the Mascarene Islands (see Carlsward et al, 2006;Micheneau et al, 2008;Andriananjamanantsoa et al, 2016), in the Neotropics (Carlsward et al, 2003;Pessoa et al, 2018), and in tropical Africa (Simo- Droissart et al, 2018a). Based on the results of Simo- Droissart et al (2018a), five papers were recently published that together have reassessed the taxonomy of most African angraecoid genera (Descourvières et al, 2018;Farminhão et al, 2018;Simo-Droissart et al, 2018b, 2018cD'haijère et al, 2019), although some groups remain to be treated. Among these, the genus Rangaeris (Schltr.)…”

“…f., Podangis Schltr., Plectrelminthus Raf., Tridactyle Schltr., and Ypsilopus Summerh. (Carlsward et al, 2006;Simo-Droissart et al, 2018a;D'haijère et al, 2019). Based on both molecular and morphological evidence, the process of dismantling Rangaeris has recently started, with one species being moved to Podangis (Cribb & Carlsward, 2012) and two species to Ypsilopus (D'haijère et al, 2019).…”

“…Given the new availability of samples from these species, we have investigated the phylogenetic relationships within Rangaeris, which could not be unraveled by Simo-Droissart (2018a). We have followed an approach combining maximum likelihood and Bayesian analyses that has proved useful for exploring relationships among angraecoids in other recent studies (Martos et al, 2017;D'haijère et al, 2019). The goal of this study is to assess the monophyly of Rangaeris by clarifying the phylogenetic position of R. longicaudata and R. trilobata relative to the generic type, R. muscicola, and of the genus relative to the other genera in the larger clade that includes Cyrtorchis and Tridactyle, using both molecular phylogenetic analyses and complementary morphological observations.…”

A near comprehensive phylogenetic framework gives new insights toward a natural classification of the African genus Cyrtorchis (Angraecinae, Orchidaceae)

“…In tropical Africa, Simo‐Droissart & al. (2018a), by providing a new molecular phylogenetic framework, have furthered our understanding of the taxonomy of continental African angraecoid orchids, and thus has enabled the taxonomic revision of many genera (Descourvières & al., 2018; Farminhão & al., 2018, 2020; Simo‐Droissart & al., 2018b,c; D'haijère & al., 2019). However, some genera are still in need of a taxonomic revision, as in the case of Cyrtorchis Schltr.…”