Reconstructing the Phylogeny ofCalliandrasect.Androcallis(Fabaceae): Insights from the Inclusion of Colombian Species, with a Focus on the Enigmatic TaxonCalliandra medellinensis

Abstract

ABSTRACTPhylogenetic relationships for the genusCalliandrasectionAndrocallis(Fabaceae) were reconstructed, including previously sequenced species from Central and South America and unexamined species from Colombia, one ofCalliandramain diversity centers. Here, we generated novel DNA sequences ofCalliandraspecies from Colombia for the nuclear Internal Transcribed Spacer (ITS)and the chloroplasttrnLandtrnL-Fintergenic spacer. By incorporating a broader taxonomic sampling, the relationships among main clades inAndrocalliswere clarified, providing a systematics framework in which to test evolutionary hypotheses. Phylogenetic analysis recovered five well-supported clades withinAndrocallis. Most species within each clade had similar geographical distributions and relationships between the five major clades are strongly supported for the first time. However, coreAndrocallisrelationships, including most species from Colombia sequenced here, remain unclear. A second goal of this study was to determine the taxonomic status ofCalliandra medellinensis. This enigmatic taxon emblematic of Medellín, Colombia, is found in limited numbers within the Aburrá Valley and has been proposed to be a hybrid taxon. Here,C. medellinensis,C. magdalenaeandC. haematocephalawere not monophyletic within the coreAndrocallisclade. This suggests thatC. medellinensiscould potentially be an interspecific hybrid betweenC. magdalenaeandC. haematocephala, thus challenging the taxonomic status of this species; however, more informative molecular markers should be used in future studies. Specifically, genomic studies should assess interspecific hybridization demographic models. Such insights can illuminate theC. medellinensisorigin, guiding conservation strategies and providing valuable evolutionary overviews.