Brunner, Anna , Douglas, Norman , Hernández-Ledesma, Patricia , Moore, Michael .
The origins and biogeography of gypsophily in Anulocaulis (Nyctaginaceae).
Anulocaulis Standl. (Nyctaginaceae) is a small arid-adapted genus of five species (one of which contains four varieties) that is endemic to southwestern North America, with a center of diversity in the Chihuahuan Desert. Taxa within Anulocaulis are usually highly localized to specific substrates, with four endemic to gypsum or gypseous soils in the Chihuahuan Desert: A. leiosolenus (Torr.) Standl. vars. howardii Spellenberg & T. Wootten, lasianthus I.M. Johnst. and gypsogenus (Waterf.) Spellenb. & T. Wootten, and A. reflexus I.M. Johnst. These taxa are termed gypsophiles. As a first step toward understanding the phylogeography of gypsophily within Anulocaulis, we reconstructed the phylogeny of the genus to address the following questions: (1) Has gypsophily evolved repeatedly, or does a single origin best explain the modern pattern of gypsophily in the genus?; (2) Is the current distribution of gypsophilic taxa within the genus best described by a relictual pattern or by dispersal following initial colonization of gypsum?; and (3) Do geographically isolated conspecific populations of Anulocaulis, particularly A. leiosolenus, display evidence of interpopulational sequence divergence, suggesting genetic isolation? To address these questions, we reconstructed the phylogeny of Anulocaulis by generating and analyzing DNA sequences for ITS and five chloroplast spacer regions (ndhF/rpl32, rpl32/trnL, ndhC/trnV, rps16/trnQ, and petA/psbJ). We sampled all taxa within Anulocaulis, as well as several outgroup taxa, including the closely related monotypic genus Nyctaginia Choisy. Multiple populations were sampled for most ingroup taxa. Preliminary results indicate that A. leiosolenus vars. gypsogenus and lasianthus form highly supported clades derived from within var. leiosolenus, and are equivocal with respect to the placement of Nyctaginia either within or as sister to Anulocaulis. Additionally, this study lays a foundation for future comparative phylogeographic studies for other gypsophilic groups within the Chihuahuan Desert.
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The Origins and Biogeography of Gypsophily in the Chihuahuan Desert
1 - Oberlin College, Biology Department, 119 Woodland St., Oberlin, OH, 44074, USA
2 - North Carolina State University, Department of Plant Biology, Campus Box 7612, Raleigh, NC, 27695, USA
3 - Universidad Nacional Autónoma de México, Depto. de Botánica, Instituto de Biología, Apdo. Postal 70-367, México, D.F., 04510, México
4 - Oberlin College, Biology Department, 119 Woodland Street, Science Center K111, Oberlin, Ohio, 44074-1097, USA
Presentation Type: Poster:Posters for BSA Sections
Location: Event Tent/Cliff Lodge
Date: Monday, July 27th, 2009
Time: 5:30 PM