bystropogon

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Molecular Ecology (2005) 14, 1177–1189

doi: 10.1111/j.1365-294X.2005.02487.x

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

Blackwell Publishing, Ltd.

J E N N I F E R L . T R U S T Y ,*¶ R I C H A R D G . O L M S T E A D ,† A R N O L D O S A N T O S - G U E R R A ,‡ S U S A N A S Á - F O N T I N H A ,§ and J A V I E R F R A N C I S C O - O R T E G A * *Department of Biological Sciences, Florida International University, University Park Campus, Miami, FL 33199, USA †Department of Biology, University of Washington, PO Box 355325, Seattle, WA 98195, USA, ‡Jardín de Aclimatación de La Orotava, Calle Retama Num. 2, Puerto de La Cruz, E-38400, Tenerife, Canary Islands, Spain, §Parque Natural da Madeira/CEM, Caminho do Meio, Bom Sucesso, PT-9050-251, Funchal, Madeira, Portugal, ¶Fairchild Tropical Botanic Garden, 11935 Old Cutler Road, Coral Gables, FL 33156, USA

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. Keywords: adaptive radiation, biogeography, evolution, molecular phylogenetics, oceanic islands, quantum speciation Received 20 October 2004; revision received 6 January 2005; accepted 6 January 2005

Introduction The Macaronesian Islands comprise the Atlantic archipelagos of the Azores, Madeira, Selvagens, Canaries, and Cape Verde. In the last 10 years, many evolutionary biology studies have focused on this region, and these island systems have played an important role in the understanding of Correspondence: Javier Francisco-Ortega, Fax: 1305 3481986; E-mail: ortegaj@fiu.edu © 2005 Blackwell Publishing Ltd

plant speciation processes in archipelagos worldwide (Baldwin et al. 1998; Juan et al. 2000; Emerson 2002; Silvertown 2004; Valido et al. 2004). Research into the interisland relationships of Macaronesian endemics gives insight into the relative roles of dispersal and ecological adaptation as evolutionary avenues (Francisco-Ortega et al. 1996, 2002; Panero et al. 1999). However, none of these studies have focused on interpreting phylogenetic patterns in the framework of the geological history of Macaronesia. The island of Tenerife (Canary Islands) has a complex geological history


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