Abstract Detail

Systematics

Bedoya, Ana Maria [1], Madriñán, Santiago [2], Olmstead, Richard [3].

Reconstructing the evolution of the aquatic habit in Neotropical Ludwigia (Onagraceae). What could this group tell us about the impact of Andean uplift in the evolution of aquatic plants in Northern South America?

The genus Ludwigia includes a variety of forms adapted to live in aquatic environments that range from humid to water saturated. Morpho-anatomical characters of roots and shoots were used to characterize and discriminate among selected Neotropical species of Ludwigia. The traits included in this study were those listed in the literature as plant adaptations to the aquatic habit. A phylogenetic hypothesis was reconstructed using nuclear and chloroplast regions, and including the same specimens studied in the morpho-anatomical study. ITS sequences of North American species were obtained from GenBank and included in the analysis as a framework for the placement of the Neotropical species. The resulting phylogeny was used to map the character states previously studied. We were able to cluster Ludwigia species into three groups based on their adaptations to the aquatic habit in a Principal Component Analysis: two groups of hydrophytes and one group of helophytes. Both groups of hydrophytes correspond to monophyletic groups. Our results support at least two separate origins for the strictly aquatic habit in Ludwigia, in line with previous taxonomic classifications. Based on our results, we suggest that the species included in this study underwent convergent evolution as a response to pressures imposed by aquatic ecosystems, but also diversified into various life forms adequate to live strictly in the water. Our results led us in the past to define Ludwigia as a good model for the study of evolution of characters that respond to selective pressured imposed by aquatic ecosystems. This time, we would discuss our current efforts using this group together with the Podostemaceae, to explore the impact of Andean uplift in the evolution of aquatic plants in Northern South America.

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Published article

1 - University of Washington, Biology, 247 Hitchcock Hall, Box 351800, Seattle, WA, 98195, USA
2 - Universidad de los Andes, Biologia, Bogota, Colombia
3 - University of Washington, Biology, Hitchcock Hall, Seattle, WA, 98195, USA

Keywords:
Aquatic plants
Neotropics
biogeography
Andean uplift.

Presentation Type: Oral Paper
Session: 19, ASPT Cooley Awards
Location: Sundance 5/Omni Hotel
Date: Tuesday, June 27th, 2017
Time: 8:30 AM
Number: 19003
Abstract ID:151
Candidate for Awards:George R. Cooley Award