Systematics/Phytogeography / Taxonomie/ Section
Symmank, Lars , Samain, Marie-Stéphanie , Goetghebeur, Paul , Mathieu, Guido , Neinhuis, Christoph , Wanke, Stefan .
Evolution of terrestrial life forms in the genus Peperomia (Piperaceae).
Peperomia (about 1600 species) is one of the largest angiosperm genera and occurs in tropical and subtropical regions worldwide. However, the highest life form diversity is encountered in the subtropical (mountainous) areas of Mexico, Central and South America. The vast majority of the species diversity has radiated with the exploration of the epiphytic life form whereas only few species are terrestrial. Phylogenetic tree reconstruction shows that three exclusively terrestrial clades are recovered as sistergroup to all other species of Peperomia. The remaining ones are predominately epiphytic. Consequently Peperomia is ancestrally a terrestrial genus. Based on our results the geophytic life form with seasonal growth has originated multiple times. Once in the primary terrestrial clade Tildenia and several times as a shift from epiphytic back to a geophytic life form via a terrestrial non-tuberous intermediate. All life forms including the intermediates are still present and representatives have been sampled allowing a gapless reconstruction of the evolutionary development of the genus. Morphologically the different geophytic life forms are well separated. Leaves and inflorescences of Tildenia originate directly from the perennial tuber whereas other tuberous species form stems with leaves and inflorescences. The species of the subgenus Tildenia occur in two biodiversity hot spots (Peru-Bolivia and Mexico-Guatemala) with few species reported from the countries in between. Phylogenetic reconstruction of Tildenia shows a grade of the Andean species with a monophyletic North American grown group. This supports the hypothesis of radiation out of South America after the forming of the Central American land bridge in the early Pleistocene.
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1 - Technische Universitaet Dresden, Institut fuer Botanik, Dresden, 01062, Germany
2 - Ghent University, Department of Biology, Research Group Spermatophytes, Ghent, 9000, Belgium
3 - Ghent University, Department of Biology, Research Group Spermatophytes, K.L.Ledeganckstraat 35, Gent, Belgium, B-9000
4 - Ghent University, Department of Biology, Research Group Spermatophytes, Ghent, 9000, Belgium
5 - Technische Universitaet Dresden, Intitut fuer Botanik, Dresden, 01062, Germany
Central American land bridge.
Presentation Type: Oral Paper:Papers for Sections
Location: Room 6/Woodward
Date: Tuesday, July 29th, 2008
Time: 11:00 AM