CONICET | Buscador de Institutos y Recursos Humanos

We performed phylogenetic analyses on different populations of eight taxa from the Tillandsia capillaris complex within subgenus Diaphoranthema, a polymorphic and (tetra-) polyploid group of highly specialized Tillandsia, distributed in mountanous arid regions from central Peru and Bolivia to northern and centralArgentina and Chile. We aimed to investigate the evolutionary relationships and phylogeographic patterns among microtaxa of the complex with chloroplast and low-copy nuclear markers. We obtained sequences from almost 100 individuals from 69 populations of the complex in addition to more than 20 outgroup taxa.We edited and aligned two matrices, one made of three plastid markers (rpoB-trnC-petN, ycf1, matK-trnK) with 8100 bp, and another of the nuclear marker (phyC) with 1200 bp. We constructed Bayesian phylogenetic trees and only unrooted phylogenetic networks for the nuclear marker. For the phylogeographic analyses, chloroplast markers were used and haplotype networks using parsimony and Bayesian trees were rebuilt. Both datasets, the plastid and nuclear, indicated the existence of two main evolutionary lineages, which could berecognized in the two species proposed by Till in 1984: T. capillaris and T. virescens, this last group includes T. kuehhasii (described in 1995 as outside the complex). The nuclear data had less resolution but still two main groups can be distinguished; only a few individuals identified morphologically as ?capillaris? appear in the ?Virescens? group, results that hint at hybridization. Regarding phylogeographic patterns, the distribution of 63 cpDNA haplotypes in 69 populations also resulted in two main lineages co-ocurring from northern Peru to southern Argentina and Chile, with high haplotype diversity and a set of haplotypes defined for each species. Despite the geographic similarities, including the presence of both species in some localities, we found some differences between the two main lineages. T. capillaris is molecularly and morphologically a homogeneous group and comprises populations with enough genetic variation to seemingly have the ability to expand into new habitats but maintain enough cohesion to be recognized as part of the same reproductive unit. T. virescens is genetically and morphologically more divergent with most of the forms growing in high and arid mountains and a recent subclade "Cordobensis" growing in low and moist montane habitats from central Bolivia and Argentina. Results suggest evidence of ancient speciation for the two main clades of the T. capillaris complex, and a complex evolutionary history involving geographic expansion, adaptive radiation and probably polyploidization events.