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Abstract Detail



Systematics Section/ASPT

Livshultz, Tatyana [1], Liede, Sigrid [2], Meve, Ulrich [3], Forster, Paul [4], Wanntorp, Livia [5].

Phylogeny of Marsdenieae (Apocynaceae, Asclepiadoideae) and circumscription of Marsdenia R.Br. based on chloroplast and nuclear loci.

We present the first taxonomically densely sampled molecular phylogenetic analysis of Marsdenieae, a pan-tropical, predominantly forest-dwelling lineage of about 570 species classified into 29 genera in the most recent revision (Omlor, 1998). Most Marsdenieae species are woody lianas with the notable exception of Hoya (ca. 100 spp.) and Dischidia (ca. 80 spp.), species of which are mostly succulent epiphytic vines. Several species are important in traditional pharmacopias and currently the objects of active research for anti-diabetic and anti-tumor activity. The circumscription of Marsdenia R. Br. has been particularly problematic and variable ranging from Marsdenia sensu Bullock (ca. 8 Asian species closely related to the type M. tinctoria) to Marsdenia sensu Forster (ca. 250 species distributed throughout the range of the tribe with the segregate genera Gongronema, Stephanotis, Dregea, Wattakaka, Cionura, and Gymnema all in synonoymy). We sequenced parts of the chloroplast (trnT-trnF introns and spacers and rps16 intron) and two single copy nuclear loci (At2g06530 and At2g34620) from 102 species from 20 of the 29 genera recognized by Omlor as well as outgroups from the other Asclepiadoideae tribes. In parsimony and likelihood analyses, Marsdenia sensu lato is highly polyphyletic, divided among three (3) primary clades: 1) an Asian-Australasian clade that includes the epiphytes Dischidia and Hoya and the type species, M. tinctoria; 2) a small African clade that includes the monotypic South African genus Rhyssolobium and two Madagascan species of Marsdenia; and 3) a cosmopolitan clade that includes the rest of Marsdenieae with four (4) moderately to well-supported sub-clades that span tropical Asia and Africa. All American species of Marsdenia form a monophyletic sub-clade of the cosmopolitan clade. A monophyletic Marsdenia sensu lato would subsume all species of Marsdenieae. We discuss alternative classifications that maintain Dischidia and Hoya as distinct genera and morphological characters that can be used to diagnose subclades of this phylogeny.

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1 - Academy of Natural Sciences of Drexel University, Department of Biodiversity, Earth, and Environmental Sciences, 1900 Benjamin Franklin Parkway, Philadelphia, Pennsylvania, 19103, USA
2 - University of Bayreuth, Dept. of Plant Systematics, Bayreuth, 95440, Germany
3 - University of Bayreuth, Bayreuth, 95440, Germany
4 - Queensland Herbarium, Mt Coot-tha Road, Toowong, Brisbane, Queensland, 4066, Australia
5 - Swedish Museum of Natural History, Sweden

Keywords:
Apocynaceae
Asclepiadoideae
phylogeny
nuclear markers
amphitropical
bioigeography
classification.

Presentation Type: Oral Paper:Papers for Sections
Session: 33
Location: Rosedown/Riverside Hilton
Date: Tuesday, July 30th, 2013
Time: 1:30 PM
Number: 33001
Abstract ID:346
Candidate for Awards:None


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