Weeks, Andrea .
Invasion, radiation and evolution of Malagasy Commiphora (Burseraceae).
Commiphora Jacq. comprises ca. 190 tree species distributed in the seasonally dry (sub-) tropics of Africa, Madagascar, the Indian Ocean basin, and South America. Previous molecular phylogenetic work has indicated that the genus radiated during the late Oligocene to early Miocene and invaded the island continent of Madagascar at least twice thereafter. All Malagasy Commiphora species are endemic (29 spp. plus 16-18 newly discovered species) and, like other members of the genus, have a range of succulent stem morphologies that may be correlated with their ability to store resources and thrive in environments that experience periods of extreme water deficit. Thus, the separate Malagasy Commiphora lineages provide an opportunity to study the morphological and physiological consequences of species radiation in parallel. For instance, theory would predict that the earliest arriving lineage would have both a faster rate of speciation and a broader range of morphologies due to lack of conspecific competition. Here, we test our assumption that Malagasy Commiphora species comprise two separate lineages by analyzing DNA sequence data from newly collected species and provide the first measurements of stem anatomical diversity in these clades.
Provides an in-depth examination of the evolutionary processes that have generated these lineages in Madagascar and contributes to the broader understanding of the forces involved in angiosperm radiation.
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1 - George Mason University, Department of Environmental Science and Policy 5F2, Fairfax, Virginia, 22030, USA
Presentation Type: Poster:Posters for Sections
Location: Hall A/Convention Center
Date: Monday, August 2nd, 2010
Time: 5:30 PM