Otto, Elisabeth , Schneider, Harald .
Reconstructing the adaptive radiation of the ephiphytic, neotropical fern genus Pleopeltis (Polypodiaceae).
The phylogeny of the Pleopeltis clade within the Polypodiaceae is inferred using four chloroplast genome markers: The coding regions rbcL and rps4 and the non-coding regions rps4-trnS IGS and trnL-trnF IGS. The taxonomic sampling comprises one or more samples of more than 30 fern species earlier classified as members of the genera Dicranoglossum, Microphlebodium, Neurodium, Pleopeltis, Polypodium, and Pseudocolysis. Perviously published phylogenetic analyses have suggested that these species form a monophyletic lineage within an assemblage of mainly Neotropical ferns that were partly assigned to the polyphyletic genus Polypodium. This study is part of ongoing efforts to understand the classification of the fern family Polypodiaceae based on molecular phylogenetic reconstruction. Our results show that there is a need to redefine the genus Pleopeltis because the group in its current circumscription is not monophyletic. This supports the previous suggestion to combine all species that fall into the Pleopeltis clade in one genus. Persistent scales on the lamina and/or rachis are a putative apomorphy of this genus, whereas peltate paraphyses evolved at least twice in this clade. We found strong support for the P. squamatum group and also evidence for a clade comprising P. macrocarpa and its relatives. Other species with simple leaves, e.g. P. astrolepis and P. wiesbaueri appear to form the sister group to the latter clade. The inferred phylogeny will not only shed light onto the classification of one of the most widespread and species rich genera in Polypodiaceae but will also allow us to unravel the adaptive radiation of these epiphytic ferns. The key innovation that might have triggered their diversification is the tolerance of water stress including poikilohydry as an extreme response.
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1 - Universität Göttingen, Albrecht von Haller Institut für Pflanzenwissenschaften, Abteilung für Systematische Botanik, Untere Kaspüle 2, Göttingen, 30703, Germany
2 - Natural History Museum, Cromwell Road, London, SW7 5BD, UK
Presentation Type: Poster:Posters for Sections
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM