| Abstract Detail
Systematics/Phytogeography / Taxonomie/ Section Saslis-Lagoudakis, Charilaos [2], Chase, Mark W. [1], Robinson, D. [2], Russell, Stephen J. [2], Klitgaard, Bente [2]. Phylogenetics of Neotropical Platymiscium (Leguminosae: Dalbergieae): systematics, divergence times and biogeography inferred from nuclear ribosomal and plastid DNA sequence data. Platymiscium is a Neotropical legume genus of forest trees in the pantropical clade of “dalbergioid” legumes. It comprises 19 species (29 taxa) and is distributed from Mexico to southern Brazil. It is favored by the timber industry, and several species are endangered to various extents. This study presents a molecular phylogenetic analysis of the genus and allies inferred from nuclear ribosomal (nrITS) and plastid (trnL, trnL-F and matK) DNA regions using parsimony and Bayesian methods. Divergence times are estimated using a Bayesian method assuming a relaxed molecular clock (multidivtime). Relationships among other genera of the Pterocarpus clade are discussed. Our results support monophyly of the genus, which is resolved into three major clades, with distinct geographic ranges. The implications for the taxonomy of the genus are discussed. Diversification in Platymiscium has been driven by allopatric processes and ecological diversification. We hypothesize that the genus arose in South America and radiated northwards. It invaded the Amazon basin twice both within the last 3.5 Ma and Central America twice both before the closure of the Isthmus of Panama. Divergence times of the P. pubescens complex, restricted to the seasonally dry tropical forests (SDTF) of South America, provide an insight into their history.
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1 - Royal Botanic Gardens, Kew, Jodrell Laboratories, Richmond, Surrey, TW9 3DS, United Kingdom
2 - Natural History Museum, Department of Botany, London, SW7 5BD, United Kingdom
Keywords:
Biogeography
divergence times
Leguminosae
Neotropics
Pterocarpus clade
Seasonal Dry Tropical Ecosystems
Platymiscium
systematics.
Presentation Type: Oral Paper:Papers for Sections
Session: 35
Location: 169/Law
Date: Tuesday, July 29th, 2008
Time: 10:15 AM
Number: 35009
Abstract ID:271 |
