Molecular phylogenetics of the Macaronesian-endemic genus Bystropogon (Lamiaceae): palaeo-islands, ecological shifts and interisland colonizations

Authors

  • JENNIFER L. TRUSTY,

    1. Department of Biological Sciences, Florida International University, University Park Campus, Miami, FL 33199, USA
    2. Fairchild Tropical Botanic Garden, 11935 Old Cutler Road, Coral Gables, FL 33156, USA
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  • RICHARD G. OLMSTEAD,

    1. Department of Biology, University of Washington, PO Box 355325, Seattle, WA 98195, USA,
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  • ARNOLDO SANTOS-GUERRA,

    1. Jardín de Aclimatación de La Orotava, Calle Retama Num. 2, Puerto de La Cruz, E-38400, Tenerife, Canary Islands, Spain,
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  • SUSANA SÁ-FONTINHA,

    1. Parque Natural da Madeira/CEM, Caminho do Meio, Bom Sucesso, PT-9050-251, Funchal, Madeira, Portugal,
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  • JAVIER FRANCISCO-ORTEGA

    Corresponding author
    1. Department of Biological Sciences, Florida International University, University Park Campus, Miami, FL 33199, USA
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Javier Francisco-Ortega, Fax: 1305 3481986; E-mail: ortegaj@fiu.edu

Abstract

A molecular phylogenetic study of Bystropogon L’Hèr. (Lamiaceae) is presented. We performed a cladistic analysis of nucleotide sequences of the internal transcribed spacers (ITS), of the nuclear ribosomal DNA, and of the trnL gene and trnL-trnF intergenic spacer of the chloroplast DNA. Bystropogon odoratissimus is the only species endemic to the Canary Islands that occurs in the three palaeo-islands of Tenerife. This species is not part of an early diverging lineage of Bystropogon and we suggest that it has a recent origin. This phylogenetic pattern is followed by most of the species endemic to the palaeo-islands of Tenerife. The two sections currently recognized in Bystropogon form two monophyletic groups. Taxa belonging to the section Bystropogon clade show interisland colonization limited to the Canary Islands with ecological shifts among three ecological zones. Taxa from the section Canariense clade show interisland colonization both within the Canary Islands and between the Canary Islands and Madeira. Speciation events within this clade are mostly limited to the laurel forest. The genus has followed a colonization route from the Canaries towards Madeira. This route has also been followed by at least five other plant genera with species endemic to Macaronesia. Major incongruences were found between the current infrasectional classification and the molecular phylogeny, because the varieties of Bystropogon origanifolius and Bystropogon canariensis do not form two monophyletic groups. The widespread B. origanifolius appears as progenitor of the other species in section Bystropogon with a more restricted distribution.

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