Martinez, Nirzka , Santiago, Eugenio , Salazar, Jackeline .
Caribbean Tabebuia (Bignoniaceae): Insights on their origin, diversification and taxonomic circumscription based on a preliminary phylogenetic analysis.
Tabebuia Gomes ex.DC. is an extraordinarily diverse plant genus that comprises species of ethnobotanical and economical importance. Traditionally the genus circumscribed ca. 100 Neotropical species, with many (ca. 60 species) confined to the Greater Antilles, especially to the islands of Cuba and Hispaniola. The genus exhibits great morphological variability and adaptations to a wide array of environmental conditions ranging from dry coastal scrubs to the cloud forests of high elevations. These characteristics make Tabebuia an interesting case to assess plant radiation in the Caribbean islands. Previous molecular studies based on chloroplast data indicate that the genus is paraphyletic, supporting a taxonomic revision that has separated the traditional Tabebuia or Tabebuia sensu lato into three genera: Handroanthus, Roseodendron and Tabebuia. Still, the relationships between the many species in the Caribbean have not been elucidated. The objective of this research is to test the monophyly of the Caribbean species of Tabebuia, and to evaluate their evolutionary relationships, diversification, and biogeography. A preliminary phylogeny has been constructed based on chloroplast (psbD-trnT and rpl32-trnL) and nuclear (ITS and PPR AT5G39980) DNA sequences. Results confirm that Caribbean species are part of Tabebuia sensu stricto by the position of T. cassinoides, the genus type species, which has not been included in previous studies. In addition, preliminary results indicate that the sampled Caribbean Tabebuia form a clade in which continental lineages are in a basal position. While the island species appears to be monophyletic, the phylogeny further supports that Tabebuia, as was known traditionally (i.e., including Handroanthus), is not monophyletic by the position of members of Crescentia, Spirotecoma and Ekmanianthe. The results also support the description of new species from Hispaniola, as well as highlight the need for further evaluation of material from taxa that has been previously synonymized or possibly wrongly classified (particularly within the T. heterophylla complex). Although additional sampling and molecular analyses are currently underway, preliminary results clearly show the complexity of the evolutionary history of the genus. Financial support: University of Puerto Rico (NSF-CREST Program, Biology Department-RioPiedras campus and Botanical Garden Herbarium); Ministerio de Educacion Superior, Ciencia y Tecnologia de Republica Dominicana (MESCyT).
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1 - University Of Puerto Rico - Rio Piedras Campus, Biology Department, PO Box 23360, San Juan, PR, 00931-3360, USA
2 - Universidad De Puerto Rico-Rio Piedras, Department Of Biology, Apartado 70377, San Juan, PR, 00936-8377, Puerto Rico
3 - Universidad Autonoma De Santo Domingo, Ciudad Universitaria, DN, N/A, 10030, Dominican Republic
Presentation Type: Poster:Posters for Sections
Location: Battelle South/Convention Center
Date: Monday, July 9th, 2012
Time: 5:30 PM