Systematics Section / ASPT
Mansion, Guilhem , Ree, Richard , Conti, Elena .
Biogeographic history of the Araceae in the Mediterranean region, with emphasis on the origin of Corso-Sardinian endemics.
DESPITE the remarkable species-richness of the Mediterranean flora, relatively few studies have investigated the temporal and spatial origins of this extraordinary diversity. Here, we use a combined approach including molecular phylogenies from four cpDNA regions, dating analyses, and paleogeographic reconstructions to elucidate the time frame and sequential events associated with the diversification of the Araceae in the Mediterranean basin. This mainly tropical family has a relatively rich fossil record that can provide multiple calibration points for dating analyses and the seven genera currently occurring in the Mediterranean do not present obvious long-distance dispersal syndromes. Furthermore, most of the species have a narrow distribution, or are endemic to islands such as Corsica, Sardinia, or the Balearic Archipelago. The mentioned islands have a complex but well-known paleogeology, thus providing a solid framework to reconstruct their biogeographic history. Preliminary results show two main episodes of colonization of the Mediterranean from likely tropical ancestors. The (Arisarum + Ambrosinia) clade (Peltandreae) diverged in the late Eocene — Early Oligocene, likely before the separation of the Corso-Sardinian microplate from the Iberian plate. The occurrence of Ambrosinia in Corsica, Sardinia, Sicily and North Africa may reflect middle Miocene connections (15 - 18 million years ago) between these areas. Within the Areae, five genera of primarily Mediterranean distribution form a monophyletic group of late Oligocene - Early Miocene origin. Helicodiceros (Corsica, Sardinia, Balearic Archipelago) forms a clade with the eastern Mediterranean Eminium, while Biarum (Mediterranean Europe, Middle East, and North Africa) is sister to the (Dracunculus + Arum) clade (Macaronesia, Europe to Central Asia). Hypotheses concerning the tempo and mode of origin of Helicodiceros muscivorus and Arum pictum in Corsica, Sardinia, and the Balearic Islands are discussed.
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1 - Universität Zürich, Institut für Systematische Botanik, Zollikerstrasse 107, Zürich, CH-8008, Schweiz
2 - Field Museum of Natural Hististory, Department of Botany, 1400 South Lake Shore Drive, Roosevelt Rd At Lake Shore, Chicago, Illinois, 60605-2496, USA
Presentation Type: Poster:Posters for Sections
Location: Auditorium/Bell Memorial Union
Date: Tuesday, August 1st, 2006
Time: 12:30 PM