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Abstract Detail



Systematics Section/ASPT

Waselkov, Katherine [1], Olsen, Kenneth [2], Schaal, Barbara [3].

Opportunists in the Lava Fields: Diversification of the Genus Amaranthus in the Galápagos Islands.

The Galápagos Islands are well known for spectacular adaptive radiations in animals, including finches, giant tortoises, and land snails. However, the phylogeography of plant groups in the islands has been less frequently studied, despite multiple Galápagos endemics occurring in several genera. Our study genus, Amaranthus, contains about 75 species native to warm temperate and tropical regions throughout the world, with several individual weedy species having a nearly worldwide distribution. Three endemic Amaranthus species and one native species are found Galápagos, and their evolutionary relationships to each other and other species in the genus have not previously been studied with molecular methods. We have included three of these species in our generic molecular phylogeny using four low-copy nuclear genes and two chloroplast markers, and discovered that each appears to represent an independent colonization of the islands from North America. These results are congruent with morphological features of each species and their putative closest relatives. In addition, two collections previously identified as the more widespread endemic A. sclerantoides are shown to be more closely related to the Caribbean species A. crassipes, and may be a new endemic species, found only on two islands.

Broader Impacts:


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1 - Washington University In St. Louis, 1 Brookings Drive, Campus Box 1137, Saint Louis, MO, 63130, USA
2 - Washington University, BIOLOGY DEPT, BOX 1137, 1 BROOKINGS DRIVE, St. Louis, MO, 63130-4899, USA
3 - Washington University, Department of Biology, CAMPUS BOX 1137, 1 Brookings Drive, St. Louis, MO, 63130-4899, USA

Keywords:
Galápagos
Amaranthus
Phylogeography
endemic flora.

Presentation Type: Oral Paper:Papers for Sections
Session: 11
Location: Magnolia/Riverside Hilton
Date: Monday, July 29th, 2013
Time: 4:00 PM
Number: 11010
Abstract ID:270
Candidate for Awards:George R. Cooley Award


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