Weising et al. 2015 (Conference Paper) Pitcairnioideae

Phylogeographic patterns in Bromeliaceae: examples from Pitcairnioideae s.s.

Author(s):—K. Weising, N. Wagner, N. Schütz, F. Krapp, T. Wöhrmann & K. Schubert in Benko-Iseppon, A.M.; Alves, M. & Louzada, R. (2015) An overview and abstracts of the First World Congress on Bromeliaceae Evolution. Rodriguésia 66(2): A1-A66.

Publication:— (2015).

Abstract:—The present talk aims to summarize our current knowledge about phylogenetic relationships among the five genera of Pitcairnioideae s.s., the time scales in which they diversified, and phylogeographic patterns that havebecome apparent within the subfamily. The presented trees and networks are based on sequence data from several chloroplast DNA (cpDNA) loci and the nuclear PHYC gene. On the subfamily level, we analyzed ~30 accessions per genus covering the whole distribution area. The widely distributed genus Pitcairnia is mono-phyletic and sister to the remainder of the subfamily in all trees. Next-branching is the likewise monophyletic genus Fosterella, which is sister to a well-supported xeriphytic clade consisting of Deuterocohnia, Dyckia and Encholirium. The Andean genus Deuterocohnia is paraphyletic in the cpDNA tree but monophyletic in the nuclear tree, suggesting an ancient chloroplast capture event. Dyckia is monophyletic and arises from within a paraphyletic Encholirium. The two latter genera have their diversity centres in the Brazilian Cerrado and Caatinga. Since Pitcairnia, Fosterella, Deuterocohnia and Encholirium will be covered by separate talks in this session, I will put some focus on Dyckia that comprises 158 species with a strongly xeromorphic habit.DNA sequence variation within Dyckia turned out to be extremely low, and phylogenies were hence poorly resolved. A dated cpDNA phylogeny suggests that Dyckia experienced a rather recent radiation beginning around 2.9 Mya. A recent expansion was also suggested by a star-like pattern of a parsimony network based on cpDNA haplotypes. Four major clades were identified that roughly corresponded to the geographic origin of the accessions. Our current working hypothesis based on molecular data and geographical distribution of extant taxa is that the common ancestor of Dyckia and Encholirium started to diversify in NE Brazil where Encholirium still resides nowadays. At least one lineage of Dyckia dispersed to S Brazil, from where a rapid colonization of suitable habitats was initiated. We hypothesize that the radiation of the genus has been triggered by the climatic oscillations of the Cenozoic.

Keywords:—Dated Chloroplast Phylogeography; Haplotype Network; Dyckia.