The evolution of afro-montane Delphinium (Ranunculaceae): Morphospecies, phylogenetics and biogeography

Author(s)
Marion Chartier, Stefan Dressler, Jürg Schönenberger, Alfonso Rojas Mora, Corinne Sarthou, Wei Wang, Florian Jabbour
Abstract

The genus Delphinium (Ranunculaceae) consists of ca. 300 species and has a mainly holarctic distribution. Few species have been described from high-altitude areas in West and East Tropical Africa, where the environmental conditions are mostly temperate-like. We aim to clarify the taxonomy of these afro-montane Delphinium species and to understand their evolutionary history in terms of their floral morphology and their phylogenetic and biogeographic relationships. Based on herbarium specimens, we analyze flower shape variation, map the geographic distribution of the morphologically defined taxa and reconstruct the molecular phylogeny of the group. Our quantitative analyses of flower shapes indicate that three species can be defined based on floral morphological traits, hence confirming the latest taxonomic treatment of the group where D. dasycaulon, D. leroyi and D. macrocentrum were described. The examination of herbarium specimens indicates that these three species are almost parapatric. However, their respective monophyly is not supported by molecular data. Considering their relatively young age, the non-monophyly of each of the three morphospecies could be due to incomplete lineage sorting and/or hybridization events. Alternatively, the transition to the D. leroyi floral morph could be the result of evolutionary convergence in the two main groups of afro-montane Delphinium driven by similar pollinators in different sky islands of the East African Rift System. We hypothesize that the main branches of the East African Rift System, as physical barriers to dispersal, may have prevented genetic exchange among geographic clusters.

Organisation(s)
Department of Botany and Biodiversity Research
External organisation(s)
Senckenberg Forschungsinstitut und Naturmuseum, Université de Neuchâtel, Chinese Academy of Sciences (CAS), Museum national d'Histoire Naturelle, Ludwig-Maximilians-Universität München
Journal
Taxon
Volume
65
Pages
1313-1327
No. of pages
15
ISSN
0040-0262
DOI
https://doi.org/10.12705/656.6
Publication date
2016
Peer reviewed
Yes
Austrian Fields of Science 2012
106042 Systematic botany, 106008 Botany, 106012 Evolutionary research
Keywords
Portal url
https://ucris.univie.ac.at/portal/en/publications/the-evolution-of-afromontane-delphinium-ranunculaceae-morphospecies-phylogenetics-and-biogeography(60573843-2e1f-4365-b5a7-e98fff7bd08e).html