Tuesday, March 30, 2021

[Botany • 2021] Phylogeny of Anisopappus (Asteraceae: Athroismeae) with Species Circumscriptions revisited


A, Anisopappus paucidentatus from Chimanimani mountains, Mozambique;
 B & C, Anisopappus lastii subsp. lastii from Pico Muli, Mozambique;
D & E, Anisopappus buchwaldii subsp. iodotrichus from Serra Choa, Mozambique;
 F, Anisopappus davyi from Mutinodo Wilderness, Zambia.

in Bengtson, Osborne & Anderberg, 2021. 
— Photos by Jo Osborne, B & C taken during an expedition to Mt. Lico and Pico Muli in Mozambique organized by Julian Bayliss.

Abstract
Anisopappus (Asteraceae: Athroismeae) is a genus with its main distribution in Africa (one species also in Asia), currently considered to include around 21 species. A molecular phylogenetic study of Anisopappus is presented for the first time, based on plastid (ndhF, trnL‐trnF, trnQ‐rps16) and nuclear (ETS, ITS) data. Anisopappus is confirmed to be monophyletic, and species interrelationships are resolved. The results differ from earlier treatments based on morphology, and the phylogenetic analyses reveal a need for changes in species circumscriptions as compared to those of the most recent treatment. Consequently, many taxa currently treated as synonyms are here shown to represent separate species indicating that the genus includes well over 40 species. Distribution patterns now emerge where several clades are found to consist of species restricted to a particular geographical region. The Anisopappus of Madagascar, many of which were earlier placed in synonymy with species found on the African continent, are here shown to be endemic, and the results reveal a need for further studies of that group.

Keywords: Anisopappus, Asteraceae, Athroismeae, Compositae, molecular phylogenetics, taxonomy

 
Representatives of Anisopappus.
A, Anisopappus paucidentatus from Chimanimani mountains, Mozambique; capitula ca 2.2 cm diam.; B & C, Anisopappus lastii subsp. lastii from Pico Muli, Mozambique; capitula ca 1.6 cm diam.;
D & E, Anisopappus buchwaldii subsp. iodotrichus from Serra Choa, Mozambique; capitula ca 2.8 cm diam.; F, Anisopappus davyi from Mutinodo Wilderness, Zambia; capitula ca 1.8 cm diam.

— Photos by Jo Osborne, B & C taken during an expedition to Mt. Lico and Pico Muli in Mozambique organized by Julian Bayliss.


Conclusions: 
The study presents a first molecular phylogenetic study of the genus Anisopappus that aims at resolving the relationships between the different taxa and testing earlier classifications of species delimitations. The results show the synonymization and classification of Ortiz & al. (1996; Ortiz, 2005), where a large number of species were synonymized under Anisopappus chinensis, to be largely unsupported, and instead support the classification of Wild (1964) to a major extent. The results reveal a need for changes in species circumscriptions. The number of species is here shown to be well over 40 rather than the 21 recognized prior to this study (Bengtson & al., 2017). Almost all species that were recognized prior to the revision by Ortiz & al. (1996) are resurrected. Several new species have recently been discovered, and yet more may be found as the taxa from Madagascar are studied in detail. Additionally, a few of the species recognized by Wild (1964) are here shown to consist of more than one morphologically similar taxon. Closely related species are often found in the same area, and several clades show a distinct geographical pattern with species limited to a particular region. Most of the taxa found on Madagascar form a Malagasy endemic clade, and the study reveals a need for further studies of the group.


Annika Bengtson, Jo Osborne and Arne A. Anderberg. 2021. Phylogeny of Anisopappus with Species Circumscriptions revisited (Asteraceae: Athroismeae). Taxon. DOI: 10.1002/tax.12448