Sebastian, Patrizia M. , Lira, Rafael , Cross, Hugh B. , Telford, Ian R. H. , Motley, Timothy J. , Renner, Susanne S .
Biogeography of the Siycos clade (Cucurbitaceae) – from the New World to Australia, New Zealand, and Hawaii.
Vegetable pear or chayote (Sechium edule (Jacq.) Sw. = Sicyos edulis Jacq.) has become an important export crop, with Costa Rica producing 36,000 tons/year (1993 data). We are studying its phylogenetic relationships with other species of Sicyeae currently placed in Sicyos, Sechium, Microsechium, Sechiopsis, and Parasicyos. The largest of these genera is Sicyos (50 species), which occurs in the Americas, Galapagos (1 sp., extinct), Hawaii (14 spp.), Australia (2 spp.), and New Zealand (1 sp.). Based on nuclear and chloroplast sequences for 110+ accessions covering most relevant species, all generic type species, and numerous outgroups, we found that all these genera are embedded in Sicyos, the crown group of which is 11 Â± 3 my old, judging from family-wide dating (Schaefer et al., PRSB 2009). Distant lineages within the Sicyos clade reached Australia and Hawaii by transoceanic dispersal, each colonization leading to new radiations. Contrary to morphological appearance, the genus Frantzia Pittier, with six species, is not a member of Siycos sensu lato, but constitutes a genetically distant lineage that is closest to Mexican species currently placed in Echinopepon and various micro-genera endemic in Arizona and Mexico. The Hawaiian and Australian radiations will be detailed on a poster.
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1 - University of Munich, Organismal Biology, Menzingerstr. 67, Munich, 80638, Germany
2 - Universidad Nacional Autónoma de Mexico, Facultad de Estudios Superiores Iztacala, Mexico
3 - State Herbarium of South Australia, Adelaide, Australia
4 - University of New England, N.C.W. Beadle Herbarium, Armidale, Australia
5 - Old Dominion University, Department of Biological Sciences, 110 Mills Godwin Building/45th St, Norfolk, VA, 23529-0266, USA
Presentation Type: Poster:Posters for Topics
Location: Event Tent/Cliff Lodge
Date: Monday, July 27th, 2009
Time: 5:30 PM