Tippery, Nicholas P. , Philbrick, C. Thomas , Les, Donald H. .
Systematics and phylogenetic analysis of neotropical riverweeds (Podostemaceae).
Podostemaceae (riverweeds) are a diverse and morphologically anomalous group of aquatic plants that occupy seasonally inundated areas of fast-flowing water. The family is largely pantropical, with ca. 28 genera worldwide. The present study focuses on neotropical taxa (ca. 18 genera, 160 species). Morphological complexity, difficulties in recognizing structural homology, and environmentally induced morphological variation contribute to taxonomic and phylogenetic uncertainty in neotropical Podostemaceae. A molecular phylogenetic study was undertaken using nuclear (nrITS) and chloroplast (trnL-trnF) loci to determine generic boundaries and relationships among species. Although higher-order relationships were poorly resolved, the data revealed new insights. Several genera are not monophyletic as circumscribed (e.g., Oserya, Rhyncholacis). Oserya coulteriana (Mexico) is not monophyletic with species of Oserya that are disjunct in South America. The genus Castelnavia is monophyletic. Molecular data also support the recognition of fewer species of Marathrum (Mexico, Central America) and Apinagia (northern South America) than currently circumscribed. Insights from analyses of molecular data indicate significant changes need to be made to the current classification of neotropical Podostemaceae.
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1 - University of Connecticut, Ecology & Evolutionary Biology, 75 North Eagleville Road, U-3043, Storrs, Connecticut, 062693043, USA
2 - Western Connecticut State University, Biological & Environmental Sciences, 181 White Street, Danbury, CT, 06810, USA
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Presentation Type: Oral Paper:Papers for BSA Sections
Location: Maybird/Cliff Lodge - Level C
Date: Wednesday, July 29th, 2009
Time: 11:30 AM