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Abstract Detail



Systematics Section/ASPT

Toro-Nunez, Oscar [1], Mort, Mark [1].

Morphological evolution in Mathewsia and Schizopetalon (Brassicaceae), independent evolution of character states in sister related annual and perennial lineages in the Atacama Desert (Chile).

Schizopetalon (10spp) and Mathewsia (9 spp) are two small genera of Brassicaceae that are endemic to southern Peru and northern Chile, with the highest diversity of species occurring in the southern Atacama Desert. Both genera constitute a strongly monophyletic lineage that comprises exclusively annual (Schizopetalon) and perennial (Mathewsia) taxa. Previous phylogenetic studies suggest that many of the morphological features used to identify species have arisen in parallel and are of little use for estimating phylogeny within the genera. However, a detailed analysis of character evolution has yet to be conducted. Employing a recently published phylogeny of Schizopetalon and Mathewsia, character evolution is explored across Mathewsia and Schizopetalon with the goal of revealing patterns of morphological evolution and their potential association with divergent habits. Our results confirm a high level of convergence among morphological features within both genera, including features such as cotyledon structure, leaf shape, presence of inflorescence bracts and levels of pubescence. One exception to this pattern is the presence of biseriate seeds that appears to be an uncontroverted synapomorphy for Mathewsia. Each of the subclades recovered by phylogenetic analyses comprises taxa that are distributed across ecoregions of different latitudes; one possible explanation for the patterns of morphological evolution might be recurrent parallel adaptation to similar habitats among the species comprising each subclade. Regardless of the cause, our results suggest that the interpretation of the evolution in the morphology in Mathewsia and Schizopetalon should be taken carefully for taxonomic purposes.

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1 - University of Kansas, Department of Ecology and Evolutionary Biology and Biodiversity Institute, 1200 Sunnyside Ave, 6010 haworth Hall, Lawrence, KS, 66045, USA

Keywords:
none specified

Presentation Type: Oral Paper:Papers for Sections
Session: 19
Location: Napoleon Ballroom/Riverside Hilton
Date: Tuesday, July 30th, 2013
Time: 10:15 AM
Number: 19007
Abstract ID:680
Candidate for Awards:None


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