Systematics/Phytogeography / Taxonomie/ Section
Le Pechon, Timothee , Gigord, Luc D. B. , Dubuisson, Jean-Yves .
Systematics of Dombeyoideae (Malvaceae,ex-Sterculiaceae) in the Mascarene Archipelago (Indian Ocean).
The Mascarene Archipelago is characterized by an exceptional fauna and flora, especially because of its high rate of endemism. The Dombeyoideae Beilschm is one of the most diversified group of angiosperms in Mascarenes with 22 species, among which 21 are endemic - including three endemic genera - and 1 is native. We used first parsimony analysis of morphological data to examine the relationships of endemic Dombeyoideae from Mascarenes with Dombeyoideae from Africa, Madagascar and Asia. The morphological matrix included 37 representative species and 43 characters. The Dombeyoideae from Mascarene Archipelago appears polyphyletic and distributed into several clades. Phylogeny inferred from morphology is then compared with molecular data (combined trnQ-rps16, rpl16, psbM-trnD, and ITS sequences). The provided historical framework is also used for inferring evolution of important functional features such as breeding systems. This subfamily is indeed hermaphroditic in Madagascar, whereas in the Mascarenes, all the endemic species are described as dioecious. The revealed polyphyly of the Mascarene Dombeyoideae clearly suggests that in the Mascarene archipelago, dioecy has been acquired several times in independent clades. This independent acquisition could be an evolutionary convergence and could illustrate responses under insular constraints.
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1 - Pierre et Marie Curie University, UMR 5143. CNRS, Equipe 4 \"Paleodiversite, Systematique et Evolution des Embryophytes\", Batiment de Géologie, CP 48, 43 rue Buffon., Paris, France, 75005, France
2 - Université de Lausanne, Ecology and Evolution, Biophore Building, Lausanne, CH-1015, Switzerland
Presentation Type: Oral Paper:Papers for Sections
Date: Wednesday, July 30th, 2008
Time: 4:15 PM