Phylogenetic relationships in Acanthaceae based on nuclear and chloroplast sequences with particular focus on the Thunbergioideae
(English)Manuscript (preprint) (Other academic)
Phylogenetic analyses using maximum parsimony and Bayesian inference of one nuclear (ETS) and three chloroplast DNA regions (rpl16, rps16, trnT-trnL) were used to infer detailed phylogenetic relationships within the tropical and subtropical subfamily Thunbergioideae and among major lineages of Acanthaceae. For the first time, sequencing of the monotypic genus Anomacanthus is reported and its position as sister to Mendoncia gains strong support. Relationships among South and Central American Mendoncia species are poorly resolved, most likely reflecting an earlier rapid radiation. The clade with Anomacanthus and Mendoncia is sister to the clade comprising Pseudocalyx and Thunbergia. Relationships within the larger genus Thunbergia are generally well resolved. Two species (Thunbergia heterochondros and T. colpifera) appear morphologically intermediate between Pseudocalyx and Thunbergia. We discuss evolutionary relationships, including unclear species boundaries revealed by the molecular data, in a morphological context. Relationships among and within the four genera shed light on the biogeographic history of the group. All four genera are represented in Africa, from where Mendoncia appears to have dispersed to South and Central America and subsequently diversified into a large number of closely related species. The geographic origin of Thunbergia is uncertain, and the data point to interesting biogeographical patterns in this genus.
Anomacanthus, biogeography, Lamiales, morphology, Nelsonia, Pseudocalyx
Research subject Plant Systematics; Plant Morphology; Systematic Botany
IdentifiersURN: urn:nbn:se:su:diva-71076OAI: oai:DiVA.org:su-71076DiVA: diva2:483774